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Central heating system conundrum
Hoping for some guidance..
History: - About four weeks ago I noticed the the radiators were taking longer and longer to warm up. - I decided (for no reason other than it's never been done for 7 years) that the system is probably gunged up, and needs draining and refilling. - Most of our radiators are at least 30 years old; it is a microbore system (dammit); inhibitor was put in when the system was last filled, 7 years ago. - I was delayed in booking a plumber by a holiday, and by a family visit. - While the family were here (last weekend) the system packed up altogether: no heat to the radiators, and the hot water not working well either. Then the boiler started to stall, with a "Circulation Fault" (this is a Glow Worm Flexicom HX, Fault code 25). Current status: - (Assisted by a Google search on the relevant fault code), I was encouraged in my belief that the system is bunged up and needs flushing. However ... - ... two different plumbers whom I've contacted (both unavailable for weeks btw) both said there's no reason why it should be bunged up if there is inhibitor in the system. - So could it be the pump that needs renewing? Or perhaps the 3-way valve? Or maybe there's a boiler fault? But ... (a) the pump makes a noise like it's working (it's on speed 2 of 3); (b) and the 3-way *seems* to work, in that the relevant pipes get warm at the relevant heating stages; (c) and the boiler doesn't *seem* to be complaining, other than stopping with the Fault Code when it's had enough of trying to reach, and sustain, operating temperature. The two plumbers I've contacted aren't available for a fortnight, and moreover seem reluctant to take on this sort of job. I am willing (and moderately able) to do "something" myself, but I'm extremely chary of doing anything, unless I know what the "something" ought to be. For example I would drain the system and refill, if I could be confident of doing it correctly -- there's ample opportunity for screwing things up worse than they are already. If anyone's got any broad-stroke advice for my next move, I'd be very grateful. I'm well aware, btw, of the excellent section in the Wiki, http://wiki.diyfaq.org.uk/index.php?...tegory:Heating but (as I have been saying ad nauseam) I'm not sure where to start. John "Thank goodness it's Spring" |
Central heating system conundrum
In article ],
Another John writes: Hoping for some guidance.. History: - About four weeks ago I noticed the the radiators were taking longer and longer to warm up. - I decided (for no reason other than it's never been done for 7 years) that the system is probably gunged up, and needs draining and refilling. - Most of our radiators are at least 30 years old; it is a microbore system (dammit); inhibitor was put in when the system was last filled, 7 years ago. - I was delayed in booking a plumber by a holiday, and by a family visit. - While the family were here (last weekend) the system packed up altogether: no heat to the radiators, and the hot water not working well either. Then the boiler started to stall, with a "Circulation Fault" (this is a Glow Worm Flexicom HX, Fault code 25). Current status: - (Assisted by a Google search on the relevant fault code), I was encouraged in my belief that the system is bunged up and needs flushing. However ... - ... two different plumbers whom I've contacted (both unavailable for weeks btw) both said there's no reason why it should be bunged up if there is inhibitor in the system. - So could it be the pump that needs renewing? Or perhaps the 3-way valve? Or maybe there's a boiler fault? But ... (a) the pump makes a noise like it's working (it's on speed 2 of 3); (b) and the 3-way *seems* to work, in that the relevant pipes get warm at the relevant heating stages; (c) and the boiler doesn't *seem* to be complaining, other than stopping with the Fault Code when it's had enough of trying to reach, and sustain, operating temperature. The two plumbers I've contacted aren't available for a fortnight, and moreover seem reluctant to take on this sort of job. I am willing (and moderately able) to do "something" myself, but I'm extremely chary of doing anything, unless I know what the "something" ought to be. For example I would drain the system and refill, if I could be confident of doing it correctly -- there's ample opportunity for screwing things up worse than they are already. If anyone's got any broad-stroke advice for my next move, I'd be very grateful. I'm well aware, btw, of the excellent section in the Wiki, http://wiki.diyfaq.org.uk/index.php?...tegory:Heating but (as I have been saying ad nauseam) I'm not sure where to start. The pump usually has a large bleeding screw on the rear of the shaft. Unscrew this and see if the rotor is spinning. Water will leak out whilst the screw is removed, so catch it and don't let it get into any wiring. It might also be black and stain furnishings. (If it continues running out black after the initial few cc's, that would imply the inhibitor isn't working anymore.) If that's working, check for flow by feeling the hot water move along the pipe when firing up the boiler with a cold system. If that's slow (not the heating of the water, but the movement along the pipes), then either the flow is blocked, or the pump isn't pumping. Does turning the pump on to 3 make any difference? One possible failure with the pump is the impeller having disintegrated, so it has little left in terms of vanes to force the water through. This happens gradually if the pump is pumping against quite high dynamic pressure, and/or the static pressure is low at that point (causing cavitation). You would need to remove the pump and inspect the impeller to confirm this. -- Andrew Gabriel [email address is not usable -- followup in the newsgroup] |
Central heating system conundrum
On 22/04/2015 11:08, Andrew Gabriel wrote:
In ], Another writes: Hoping for some guidance.. History: - About four weeks ago I noticed the the radiators were taking longer and longer to warm up. - I decided (for no reason other than it's never been done for 7 years) that the system is probably gunged up, and needs draining and refilling. - Most of our radiators are at least 30 years old; it is a microbore system (dammit); inhibitor was put in when the system was last filled, 7 years ago. - I was delayed in booking a plumber by a holiday, and by a family visit. - While the family were here (last weekend) the system packed up altogether: no heat to the radiators, and the hot water not working well either. Then the boiler started to stall, with a "Circulation Fault" (this is a Glow Worm Flexicom HX, Fault code 25). Current status: - (Assisted by a Google search on the relevant fault code), I was encouraged in my belief that the system is bunged up and needs flushing. However ... - ... two different plumbers whom I've contacted (both unavailable for weeks btw) both said there's no reason why it should be bunged up if there is inhibitor in the system. - So could it be the pump that needs renewing? Or perhaps the 3-way valve? Or maybe there's a boiler fault? But ... (a) the pump makes a noise like it's working (it's on speed 2 of 3); (b) and the 3-way *seems* to work, in that the relevant pipes get warm at the relevant heating stages; (c) and the boiler doesn't *seem* to be complaining, other than stopping with the Fault Code when it's had enough of trying to reach, and sustain, operating temperature. The two plumbers I've contacted aren't available for a fortnight, and moreover seem reluctant to take on this sort of job. I am willing (and moderately able) to do "something" myself, but I'm extremely chary of doing anything, unless I know what the "something" ought to be. For example I would drain the system and refill, if I could be confident of doing it correctly -- there's ample opportunity for screwing things up worse than they are already. If anyone's got any broad-stroke advice for my next move, I'd be very grateful. I'm well aware, btw, of the excellent section in the Wiki, http://wiki.diyfaq.org.uk/index.php?...tegory:Heating but (as I have been saying ad nauseam) I'm not sure where to start. The pump usually has a large bleeding screw on the rear of the shaft. Unscrew this and see if the rotor is spinning. Water will leak out whilst the screw is removed, so catch it and don't let it get into any wiring. It might also be black and stain furnishings. (If it continues running out black after the initial few cc's, that would imply the inhibitor isn't working anymore.) If that's working, check for flow by feeling the hot water move along the pipe when firing up the boiler with a cold system. If that's slow (not the heating of the water, but the movement along the pipes), then either the flow is blocked, or the pump isn't pumping. Does turning the pump on to 3 make any difference? One possible failure with the pump is the impeller having disintegrated, so it has little left in terms of vanes to force the water through. This happens gradually if the pump is pumping against quite high dynamic pressure, and/or the static pressure is low at that point (causing cavitation). You would need to remove the pump and inspect the impeller to confirm this. My instinct says that the pump is duff. Presumably the HW circuit *isn't* microbore, and uses 22mm pipes? If that is the case but there's still no circulation in the HW circuit, that is very unlikely to be due to gunge. First, check that the shaft is rotating, as Andrew says. If it *isn't*, you then know where the problem lies. If it *is* rotating, it could still have a failed impeller - which you can only check by removing the pump. With a bit of luck there will be an isolation valve either side of the pump, allowing it to be removed without draining down. With even more luck, the valves will actually *work*, and not be seized up! -- Cheers, Roger ____________ Please reply to Newsgroup. Whilst email address is valid, it is seldom checked. |
Central heating system conundrum
On Wed, 22 Apr 2015 12:56:39 +0100, Roger Mills wrote:
weeks btw) both said there's no reason why it should be bunged up if there is inhibitor in the system. Hum, maybe had it had inhibitor in it for the first 23 years? The pump usually has a large bleeding screw on the rear of the shaft. Unscrew this and see if the rotor is spinning. I've never managed to peer into the hole and see the end of the shaft. It has a slot in the end though so a flat bladed screw driver can be used to see if it turns freely with the power off or is rotating with the power on (careful...). Water will leak out whilst the screw is removed, so catch it Dribbles out on my gravity systems old towel does the catching. (If it continues running out black after the initial few cc's, that would imply the inhibitor isn't working anymore.) Or that it didn't have inhibtor for the first 23 years... The water in our system is clearish black because it's a mix of old/new systems that is now inhibited. If it *is* rotating, it could still have a failed impeller - which you can only check by removing the pump. If going to all the agro of removing the pump you may as well just replace it. How old is it? 30 years if very good going 7 well it might be knackered if it's working hard with a microbore system. With a bit of luck there will be an isolation valve either side of the pump, allowing it to be removed without draining down. With even more luck, the valves will actually *work*, and not be seized up! If they are gate valves I'd put money on them a) being siezed b) if not siezed unable to shut off c) be siezed to the flanges of the pump. Be prepared to replace the valves, choose the ball type not gate, use a lighly greased (silicone not mineral) "rubber" washer not a fibre washer in the flange joint. With luck (ha, this a CH pump) you might be able to get the old valves off the pipe work and fit the new ones onto the stubbs (possibly reusing the olive and nut) and the spacing will still be correct for the pump to slide into. Don't tighten the valves onto the pipes until you have fitted the pump onto the valves and also checked that the olives seat well into the new valves. One or both olives may have to be removed (cut off). -- Cheers Dave. |
Central heating system conundrum
Thank you very much Andrew and Roger -- Roger develops Andrew's advice
and says this: My instinct says that the pump is duff. Presumably the HW circuit *isn't* microbore, and uses 22mm pipes? Yes. If that is the case but there's still no circulation in the HW circuit, that is very unlikely to be due to gunge. Lights are going on (though they may go out again soon!): I have used the immersion heater for the last couple of days to heat the water. It heats it to much hotter than the gas CH system .... and therefore it has been puzzling me why, at "hot water ON time", the CH starts to try and heat the hot water. I can hear the pump (and boiler) going for ages before I override and turn it off, muttering "WHY are you trying to heat water which is already bloody hot??" If your (joint) theory is correct, that the pump is nadgered, then this would explain that[1]: no impeller worth speaking of, but everything else working, and so the system is trying to use a pump that isn't pumping. So I need to replace the pump, as a possible fix. It's a Grundfos Super Selectric. It was installed in 2008 when the system was renovated; it is in a *vertical* orientation, in the airing cupboard next to the HW tank, so the test suggested by Andrew might be rather messy. Roger also said: First, check that the shaft is rotating, as Andrew says. If it *isn't*, you then know where the problem lies. If it *is* rotating, it could still have a failed impeller - which you can only check by removing the pump. With a bit of luck there will be an isolation valve either side of the pump, allowing it to be removed without draining down. With even more luck, the valves will actually *work*, and not be seized up! Yes! there look to be isolation valves there! No idea on the life of a pump: this one is 7 years old (almost exactly), and (of course) is used on demand, 24/7/365. Is seven years a reasonable life expectancy for a CH pump? John p.s. The system was renovated by one of the best respected (and expensive) firms in the area, but they are singularly uninterested in fixing as opposed to installing systems (I can see why, to be fair). [1] Hmm - or would it. What is the hot water thermostat for!? |
Central heating system conundrum
In article o.uk,
"Dave Liquorice" wrote: .... I've never managed to peer into the hole and see the end of the shaft. .... If going to all the agro of removing the pump you may as well just replace it. .... etc. Dave -- thanks very much for your response, which adds to what I've got already from Andrew and Roger. John |
Central heating system conundrum
In article ],
Another John writes: So I need to replace the pump, as a possible fix. It's a Grundfos Super Selectric. It was installed in 2008 when the system was renovated; it is in a *vertical* orientation, in the airing cupboard next to the HW tank, so the test suggested by Andrew might be rather messy. IIRC, the motor axis should be horizontal, or slightly angled down at the bleed screw end. This is to ensure the bearing which is lubricated by the water can't get air trapped in it, and lose its lubrication. -- Andrew Gabriel [email address is not usable -- followup in the newsgroup] |
Central heating system conundrum
On 22/04/2015 17:24, Another John wrote:
Lights are going on (though they may go out again soon!): I have used the immersion heater for the last couple of days to heat the water. It heats it to much hotter than the gas CH system .... and therefore it has been puzzling me why, at "hot water ON time", the CH starts to try and heat the hot water. I can hear the pump (and boiler) going for ages before I override and turn it off, muttering "WHY are you trying to heat water which is already bloody hot??" If the water in the cylinder is above the cylinder stat set temperature, the boiler shouldn't be trying to heat it at all - just as, when heating the HW with the boiler, the boiler should shut down when the target temperature is reached. Which makes me wonder what the setting is on the cylinder stat. If the water hasn't been getting hot because of (say) a failed pump, might you have turned the stat up in the hope of making the water hotter? It seems possible that when using the boiler, the water never got hot enough to satisfy the stat, and the boiler may have run for the entire timer on period. What happens now if you turn the stat down when the boiler is running? Does it stop? Yes! there look to be isolation valves there! That's a good start - but whether they work is another matter! No idea on the life of a pump: this one is 7 years old (almost exactly), and (of course) is used on demand, 24/7/365. Is seven years a reasonable life expectancy for a CH pump? Pumps should hopefully last longer than that - but may not. I can only remember replacing mine 3 times in 38 years - and in two of those cases the pump hadn't failed but was changed for other reasons. -- Cheers, Roger ____________ Please reply to Newsgroup. Whilst email address is valid, it is seldom checked. |
Central heating system conundrum
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Central heating system conundrum
In article ,
Roger Mills wrote: No idea on the life of a pump: this one is 7 years old (almost exactly), and (of course) is used on demand, 24/7/365. Is seven years a reasonable life expectancy for a CH pump? Pumps should hopefully last longer than that - but may not. I can only remember replacing mine 3 times in 38 years - and in two of those cases the pump hadn't failed but was changed for other reasons. Andrew's post has just given a big fat clue: following up on it, I have found the documentation from the installation in 2008: the leaflet for the Grundfos pump explicitly says what Andrew said: they should not be fitted in the vertical plane - there are diagrams, and the explanation why it shouldn't be done! :-( I remember moaning about the previous installation to the new plumber, that the pump was fitted in a confined space under the floorboards in the bathroom. The new plumber put it in the airing cupboard, which I was very pleased about: great access. It never occurred to me that they would fit it incorrectly! (Beautiful neat job, venting spurs, isolation valves, bypass valve, and stuff ..... but the pump not fitted as per specification! Looks like I need to take it off, and look at it. Or rather, get a plumber to fit a new one in the right orientation. John |
Central heating system conundrum
In message , Roger Mills
writes On 22/04/2015 17:24, Another John wrote: Lights are going on (though they may go out again soon!): I have used the immersion heater for the last couple of days to heat the water. It heats it to much hotter than the gas CH system .... and therefore it has been puzzling me why, at "hot water ON time", the CH starts to try and heat the hot water. I can hear the pump (and boiler) going for ages before I override and turn it off, muttering "WHY are you trying to heat water which is already bloody hot??" If the water in the cylinder is above the cylinder stat set temperature, the boiler shouldn't be trying to heat it at all - just as, when heating the HW with the boiler, the boiler should shut down when the target temperature is reached. Which makes me wonder what the setting is on the cylinder stat. If the water hasn't been getting hot because of (say) a failed pump, might you have turned the stat up in the hope of making the water hotter? It seems possible that when using the boiler, the water never got hot enough to satisfy the stat, and the boiler may have run for the entire timer on period. What happens now if you turn the stat down when the boiler is running? Does it stop? Or it might be that the water heated by the immersion heater doesn't go down the tank as far as the tank stat (at least not heated up to 60C or whatever)? Our immersion doesn't heat as much water as the boiler supplied pipe coil and I suspect, though haven't confirmed that when the immersion switches off, the tank stat would still be calling for heat -- Chris French |
Central heating system conundrum
On Wed, 22 Apr 2015 16:53:13 +0000 (UTC), Andrew Gabriel wrote:
IIRC, the motor axis should be horizontal, Or vertical, bleed scree up. ... or slightly angled down at the bleed screw end. My IIRC says up at the bleed end... Can't find a copy of the installation instructions online or in the dead tree system. B-( -- Cheers Dave. |
Central heating system conundrum
In article ],
Another John writes: Andrew's post has just given a big fat clue: following up on it, I have found the documentation from the installation in 2008: the leaflet for the Grundfos pump explicitly says what Andrew said: they should not be fitted in the vertical plane - there are diagrams, and the explanation why it shouldn't be done! :-( I remember moaning about the previous installation to the new plumber, that the pump was fitted in a confined space under the floorboards in the bathroom. The new plumber put it in the airing cupboard, which I was very pleased about: great access. It never occurred to me that they would fit it incorrectly! (Beautiful neat job, venting spurs, isolation valves, bypass valve, and stuff ..... but the pump not fitted as per specification! Looks like I need to take it off, and look at it. Or rather, get a plumber to fit a new one in the right orientation. Your symptoms are not obviously due to pump bearing failure though. That causes the pump to get noisy and vibrate. I suppose it could seize eventually, but I haven't come across that. Can't you just swivel it around on the pipe by slackening off and then retighening the isolating valves? I don't think this will solve your problem though. -- Andrew Gabriel [email address is not usable -- followup in the newsgroup] |
Central heating system conundrum
Another John wrote in
]: In article , Roger Mills wrote: No idea on the life of a pump: this one is 7 years old (almost exactly), and (of course) is used on demand, 24/7/365. Is seven years a reasonable life expectancy for a CH pump? Pumps should hopefully last longer than that - but may not. I can only remember replacing mine 3 times in 38 years - and in two of those cases the pump hadn't failed but was changed for other reasons. Andrew's post has just given a big fat clue: following up on it, I have found the documentation from the installation in 2008: the leaflet for the Grundfos pump explicitly says what Andrew said: they should not be fitted in the vertical plane - there are diagrams, and the explanation why it shouldn't be done! :-( I remember moaning about the previous installation to the new plumber, that the pump was fitted in a confined space under the floorboards in the bathroom. The new plumber put it in the airing cupboard, which I was very pleased about: great access. It never occurred to me that they would fit it incorrectly! (Beautiful neat job, venting spurs, isolation valves, bypass valve, and stuff ..... but the pump not fitted as per specification! Looks like I need to take it off, and look at it. Or rather, get a plumber to fit a new one in the right orientation. John A good plumber can bend and connect pipes. They are useless at reading instructions. |
Central heating system conundrum
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Central heating system conundrum
On 22/04/2015 22:05, Another John wrote:
In , (Andrew Gabriel) wrote: Can't you just swivel it around on the pipe by slackening off and then retighening the isolating valves? Um - not sure what I'd be trying to achieve there? (Sorry to be thick Andrew -- trying my best to keep up here :-) John Is the pump installed in a vertical or horizontal pipe, and in what way do you believe it to have been installed wrongly? [Better still can you upload a photograph of the pump installation somewhere, and post a link to it here?] AIUI, the axis of the pump motor needs to be horizontal or sloping up slightly towards the vent end, but *never* down. I think Andrew is assuming that the pump is installed in a horizontal pipe. If so, the motor axis can be made horizontal simply by rotating the pump body about the pipe axis. You can do this by slightly slackening the compression nuts on the remote ends of the isolating valves, rotating the pump (and valves)[1], and then re-tightening the nuts. They only need slackening a bit - not enough to cause water leaks - but put an old towel underneath, just in case! [1] Or, you could slacken the large nuts which fasten the isolation valves to the pump - and just rotate the pump and not the valves - but they are more difficult to undo and re-seal. You'll have to undo them, of course to remove the pump, but you can then clean up the faces and use new rubber washers - which you can't do if you're just slackening them for rotation. -- Cheers, Roger ____________ Please reply to Newsgroup. Whilst email address is valid, it is seldom checked. |
Central heating system conundrum
On Wed, 22 Apr 2015 19:31:45 +0100, Dave Liquorice wrote:
On Wed, 22 Apr 2015 16:53:13 +0000 (UTC), Andrew Gabriel wrote: IIRC, the motor axis should be horizontal, Or vertical, bleed scree up. ... or slightly angled down at the bleed screw end. My IIRC says up at the bleed end... Can't find a copy of the installation instructions online or in the dead tree system. B-( Your memory serves you well. The leaflet does indeed mention slightly angled up. Angled down, even very slightly, is a big no no. -- Johnny B Good |
Central heating system conundrum
On Wed, 22 Apr 2015 19:02:51 +0100, Another John wrote:
In article , Roger Mills wrote: No idea on the life of a pump: this one is 7 years old (almost exactly), and (of course) is used on demand, 24/7/365. Is seven years a reasonable life expectancy for a CH pump? Pumps should hopefully last longer than that - but may not. I can only remember replacing mine 3 times in 38 years - and in two of those cases the pump hadn't failed but was changed for other reasons. Andrew's post has just given a big fat clue: following up on it, I have found the documentation from the installation in 2008: the leaflet for the Grundfos pump explicitly says what Andrew said: they should not be fitted in the vertical plane - there are diagrams, and the explanation why it shouldn't be done! :-( I'm not sure whether you're referring to the pump being fitted into a vertical pipe run or having the pump body orientated with its shaft in a vertical plane. Since it's not clear as to exactly which of those two possibilities you mean, I feel impelled to clarify the reference to avoiding at all costs positioning the pump shaft in a vertical plane (only possible when fitted into a horizontal pipe run). Fitting the pump into a vertical pipe run is the recommended fitting option, preferably pumping upwards. However, downwards flow is allowed but only if an effective air purger and air vent is fitted before the intake side of the pump. If the vertical pipe run isn't absolutely vertical, you have to rotate the pump body so that the motor end of the shaft is level or slightly raised. If you fit the pump into a horizontal run (eg under floorboards), orientation is somewhat more critical in that you are limited to positioning the pump body so that the pump shaft is horizontal with no downward tilt or no more than just a slight upward tilt. Also, never orientate the pump body so that the pump shaft is pointed vertically (ie pump body up). I remember moaning about the previous installation to the new plumber, that the pump was fitted in a confined space under the floorboards in the bathroom. The new plumber put it in the airing cupboard, which I was very pleased about: great access. It never occurred to me that they would fit it incorrectly! (Beautiful neat job, venting spurs, isolation valves, bypass valve, and stuff ..... but the pump not fitted as per specification! Looks like I need to take it off, and look at it. Or rather, get a plumber to fit a new one in the right orientation. This is the bit of 'context' that confused me as to exactly what you meant. Our pump has always been fitted into the vertical pipework *in_the_airing_cupboard* for the past 3 decades. Admittedly, the original pump only lasted a mere 7 to 10 years before I tried a succession of alternative 'freebies' provide by my father before finally (and reluctantly) giving in and buying a Grundfoss pump some 13 to 17 years ago (the receipt has mysteriously vanished so 'best guess'). The difference between this Grundfoss and the one originally fitted was like night and day. The original had always produced a low level of vibration into the pipework from day 1. Provided the pipework wasn't contacting any other hard parts the resulting quiet hum was just a reassuring minor distraction. The new pump, however, was *so* silent, I couldn't believe it was actually running without kneeling down by the airing cupboard to listen more closely and to check the flow and return pipework to confirm that the temperature rise was on a par with previous experience. It is possible to perceive a quiet hum in the pipework just at the threshold of hearing in our bedroom when all is quiet in the late evening. The pump has remained just as quiet and effective ever since it was installed all those years ago which bodes very well for the condition of a CH & HW system that's served us well these past three decades. I never bothered with a maintenance contract of any sort and I doubt the outlay on running repairs and maintenance has averaged more than 30 quid a year tops so it owes us nothing. -- Johnny B Good |
Central heating system conundrum
In article ,
Roger Mills wrote: Is the pump installed in a vertical or horizontal pipe, and in what way do you believe it to have been installed wrongly? [Better still can you upload a photograph of the pump installation somewhere, and post a link to it here?] OK ok ok calm down John! [i.e. me!] I feel such a dumbo at times: all this talk of vertical mounting, vertical axes, etc etc confused me (I did languages and literature fellas ...) The pump is mounted in a vertical pipe. This means (**of course**, I see now) that the pump *shaft* is horizontal. And in fact the Grundfos leaflet, when I read it rather than look at the pictures, says "It is preferable to mount Grundfos circulators in a vertical pipe, pumping upwards." This is exactly what I have got: pictures! http://tinypic.com/r/295cry8/8 http://tinypic.com/r/30afiqh/8 http://tinypic.com/r/1z6a3wl/8 So: the reputation of my local firm ("highest reputation in the area") is restored, and I recant my implications of earlier :-) And: I'm now wondering what my problem is. I've now turned the CH off completely, rather than have the system doing whatever it's been doing, and having the boiler go into Fault Mode every now and then. I hope you chaps appreciate how candid I've been! I'm embarrassed about mis-interpreting the recent suggestions from Andrew and Roger and reaching a false conclusion! Off to do a day's gardening for an old lady now: a task I feel more at home with :-D John |
Central heating system conundrum
I have elevated your Plumber to being a Heating Engineer! |
Central heating system conundrum
On Thu, 23 Apr 2015 00:13:41 GMT, Johnny B Good wrote:
IIRC, the motor axis should be horizontal, Or vertical, bleed scree up. ... or slightly angled down at the bleed screw end. My IIRC says up at the bleed end... Can't find a copy of the installation instructions online or in the dead tree system. B-( Your memory serves you well. The leaflet does indeed mention slightly angled up. Angled down, even very slightly, is a big no no. I thought that the essential bit was the bleed screw to be above the impellor end but your other post gives a limit to that in horizontal pipe runs as a vertical shaft isn't allowed. Is there a photo/scan of pump installation instructions in the wiki? It not it would be a useful addition. -- Cheers Dave. |
Central heating system conundrum
On Thu, 23 Apr 2015 08:44:19 +0000, DerbyBorn wrote:
I have elevated your Plumber to being a Heating Engineer! You've replied to "The Wrong John"(tm). I'm sure "Another John" will appreciate the comment though. :-) -- Johnny B Good |
Central heating system conundrum
On Wednesday, April 22, 2015 at 5:24:13 PM UTC+1, Another John wrote:
Lights are going on (though they may go out again soon!): I have used the immersion heater for the last couple of days to heat the water. It heats it to much hotter than the gas CH system .... and therefore it has been puzzling me why, at "hot water ON time", the CH starts to try and heat the hot water. I can hear the pump (and boiler) going for ages before I override and turn it off, muttering "WHY are you trying to heat water which is already bloody hot??" I guess it is because the immersion heater has a different thermostat from the CH coil (and is set to a different temperature). Also, if both CH and HW are failing together then that suggests the circulation pump rather than gunging up. Robert |
Central heating system conundrum
On 23/04/2015 09:12, Another John wrote:
In , Roger wrote: Is the pump installed in a vertical or horizontal pipe, and in what way do you believe it to have been installed wrongly? [Better still can you upload a photograph of the pump installation somewhere, and post a link to it here?] OK ok ok calm down John! [i.e. me!] I feel such a dumbo at times: all this talk of vertical mounting, vertical axes, etc etc confused me (I did languages and literature fellas ...) The pump is mounted in a vertical pipe. This means (**of course**, I see now) that the pump *shaft* is horizontal. And in fact the Grundfos leaflet, when I read it rather than look at the pictures, says "It is preferable to mount Grundfos circulators in a vertical pipe, pumping upwards." This is exactly what I have got: pictures! http://tinypic.com/r/295cry8/8 http://tinypic.com/r/30afiqh/8 http://tinypic.com/r/1z6a3wl/8 So: the reputation of my local firm ("highest reputation in the area") is restored, and I recant my implications of earlier :-) And: I'm now wondering what my problem is. I've now turned the CH off completely, rather than have the system doing whatever it's been doing, and having the boiler go into Fault Mode every now and then. I hope you chaps appreciate how candid I've been! I'm embarrassed about mis-interpreting the recent suggestions from Andrew and Roger and reaching a false conclusion! Off to do a day's gardening for an old lady now: a task I feel more at home with :-D John Interesting pictures, which open up another possibility! You appear to have a by-pass circuit, with an automatic by-pass valve - which is relatively unusual on a Y-Plan system. [The right-angled valve with the red knob, in front of the tank]. This is supposed to provide an alternative water path during periods of pump over-run in cases where (say) all the radiator TRVs are closed. It's only supposed to open when the pump pressure rises as a result of there being no other path. *However*, if that valve were incorrectly adjusted or had failed open, most of the hot water from the boiler would take the line of least resistance and go round the by-pass rather than through the radiators or the internal coil in the cylinder. Under these circumstances, the radiators and HW would struggle to get hot even if the pump were ok. Might be worth running the system again and feeling which pipes get hot. If the pipe in and out of the by-pass valve are a lot hotter than the pipe going to the upper cylinder connection, that might be your answer! -- Cheers, Roger ____________ Please reply to Newsgroup. Whilst email address is valid, it is seldom checked. |
Central heating system conundrum
In article ,
Roger Mills wrote: The pump is mounted in a vertical pipe. This means (**of course**, I see now) that the pump *shaft* is horizontal. And in fact the Grundfos leaflet, when I read it rather than look at the pictures, says "It is preferable to mount Grundfos circulators in a vertical pipe, pumping upwards." This is exactly what I have got: pictures! http://tinypic.com/r/295cry8/8 http://tinypic.com/r/30afiqh/8 http://tinypic.com/r/1z6a3wl/8 Interesting pictures, which open up another possibility! You appear to have a by-pass circuit, with an automatic by-pass valve - which is relatively unusual on a Y-Plan system. [The right-angled valve with the red knob, in front of the tank]. This is supposed to provide an alternative water path during periods of pump over-run in cases where (say) all the radiator TRVs are closed. It's only supposed to open when the pump pressure rises as a result of there being no other path. *However*, if that valve were incorrectly adjusted or had failed open, most of the hot water from the boiler would take the line of least resistance and go round the by-pass rather than through the radiators or the internal coil in the cylinder. Under these circumstances, the radiators and HW would struggle to get hot even if the pump were ok. Might be worth running the system again and feeling which pipes get hot. If the pipe in and out of the by-pass valve are a lot hotter than the pipe going to the upper cylinder connection, that might be your answer! Wow(!). Thanks Roger. Tell you what: I ain't half glad of this burst of summer we've been having! (and of having an immersion heater as backup to the CH HW). I'll look at the by-pass valve tomorrow ... I knew what it was (because the heating engineer (thanks Derbyborn for correct terminology!) left me the pamphlet when it was installed. Don't understand a single word of it, but I have it .. Thanks again everyone, for the help. Keep it coming for as long as you like! (or until I post a glowing "job done!" report). John |
Central heating system conundrum
On Thu, 23 Apr 2015 22:47:42 +0100, Another John wrote:
Thanks again everyone, for the help. Keep it coming for as long as you like! (or until I post a glowing "job done!" report). Something else that might be worth looking at is the tank insulation. The tank stat indicates about 1/2" an inch of insulation, assuming that the back of the stat is on the metal of the cylinder (as it should be) not on top of 2" of sprayed on foam insulation. I doubt that there is any foam insulation looking at the pipe connections though. It's a big tank, one might have to play with several jackets to fully insulate it with a new layer. Also don't be afraid of putting more than one extra layer on, they aren't very thick. Two or three layers on top of what you have is not a problem and will perform better. A well insulated tank might not go down to well with SWMBO'd if the space was also used as an airing cupboard as it would now be considerably cooler. -- Cheers Dave. |
Central heating system conundrum
On 23/04/2015 10:03, Dave Liquorice wrote:
On Thu, 23 Apr 2015 00:13:41 GMT, Johnny B Good wrote: IIRC, the motor axis should be horizontal, Or vertical, bleed scree up. ... or slightly angled down at the bleed screw end. My IIRC says up at the bleed end... Can't find a copy of the installation instructions online or in the dead tree system. B-( Your memory serves you well. The leaflet does indeed mention slightly angled up. Angled down, even very slightly, is a big no no. I thought that the essential bit was the bleed screw to be above the impellor end but your other post gives a limit to that in horizontal pipe runs as a vertical shaft isn't allowed. Is there a photo/scan of pump installation instructions in the wiki? It not it would be a useful addition. Page 15 of http://uk.grundfos.com/content/dam/U...00413%20LR.pdf suggests that the OP's pump is mounted correctly. |
Central heating system conundrum
In article ,
Roger Mills wrote: http://tinypic.com/r/295cry8/8 Interesting pictures, which open up another possibility! You appear to have a by-pass circuit, with an automatic by-pass valve - which is relatively unusual on a Y-Plan system. [The right-angled valve with the red knob, in front of the tank]. This is supposed to provide an alternative water path during periods of pump over-run in cases where (say) all the radiator TRVs are closed. It's only supposed to open when the pump pressure rises as a result of there being no other path. *However*, if that valve were incorrectly adjusted or had failed open, most of the hot water from the boiler would take the line of least resistance and go round the by-pass rather than through the radiators or the internal coil in the cylinder. Under these circumstances, the radiators and HW would struggle to get hot even if the pump were ok. Might be worth running the system again and feeling which pipes get hot. If the pipe in and out of the by-pass valve are a lot hotter than the pipe going to the upper cylinder connection, that might be your answer! Probably the last entry to this thread, because I am giving up hope on isolating my problem, despite all the kind and detailed help... In response to Roger's suggestion above, this morning I did the following: * Used the two bleed-off nuts at what I will call "the pumping centre" http://tinypic.com/r/295cry8/8 in the airing cupboard: a very short hiss, then (clear) water * Taking my courage in both hands, since I have always feared that this would cause an explosive leak of water, I took off the pump bleed screw - nothing came out; I then turned the impeller with screwdriver - free. * Set the room thermostat set to 18 (normal for us). * Switched OFF the water heating, so that it was out of the equation. * Switched on the system: everything fired up. The boiler was in what I would call "boost phase": I could hear the flames roaring, and the plume was shooting out of the condenser pipe outside. * Inside a minute the boiler reached a temp of c.65 degrees, then switched off, boiler temp dropped to about 25, then it switched on again, boosted to 65, off again -- continued with this cycle -- I left off keeping an eye on it after about 15 mins. * After the first "boost" from the boiler, I had returned to the pump, removed the bleed screw again and checked if the impeller was turning - it was whizzing round; a fairly light touch with a screwdriver did not stop it. * About an hour later the room thermostat hit the set temp of 18, and everything switched off; by this time the boiler seemed to be burning fairly continuously, quietly, at about 65, with a gentle plume from the condenser pipe. * None of the radiators ever got "hot" as such - just steadily warmer. (I expect them to get hot, and thus bring up the room temperature more quickly than the over-an-hour that it took.) * The bypass seemed to be working: the pipe TO the bypass was hot, but the pipe FROM it was cold. * Finally: the pump was making its [to me, usual, and unacceptable] humming noise, and occasionally a distinct "rushing", or rather *scuttering*, noise, which must surely indicate air ... but I do not know how to remove that from the system, as I have bled all radiators, as well as the screws in the pumping centre. Later today I switched the water heating ON again, to see what would happen. This seemed to confuse things, although I can't be precise about how. So I am now suspecting the 3-way valve.... but this wouldn't explain the overall problem which kicked the whole thing off, which is that the system seems to take a long time to heat up, if at all, the boiler failing with a Fault Code (indicating "Circulation Fault"), the year-old vibration noise in the whole system, etc etc etc. Looks like I'm going to have to (a) find a heating engineer who will look at it and (b) pay him to do what I (with the vast amounts of help I've received here) have been doing ... buggering about looking for the problem. Except the heating engineer will probably simply replace one thing after another until it seems fixed, and then present me with the aggregated bill ... hence why we [try to] DIY! Thanks for all the help, everyone! John |
Central heating system conundrum
On 24/04/2015 22:30, Another John wrote:
In article , Roger Mills wrote: http://tinypic.com/r/295cry8/8 Interesting pictures, which open up another possibility! You appear to have a by-pass circuit, with an automatic by-pass valve - which is relatively unusual on a Y-Plan system. [The right-angled valve with the red knob, in front of the tank]. This is supposed to provide an alternative water path during periods of pump over-run in cases where (say) all the radiator TRVs are closed. It's only supposed to open when the pump pressure rises as a result of there being no other path. *However*, if that valve were incorrectly adjusted or had failed open, most of the hot water from the boiler would take the line of least resistance and go round the by-pass rather than through the radiators or the internal coil in the cylinder. Under these circumstances, the radiators and HW would struggle to get hot even if the pump were ok. Might be worth running the system again and feeling which pipes get hot. If the pipe in and out of the by-pass valve are a lot hotter than the pipe going to the upper cylinder connection, that might be your answer! Probably the last entry to this thread, because I am giving up hope on isolating my problem, despite all the kind and detailed help... In response to Roger's suggestion above, this morning I did the following: * Used the two bleed-off nuts at what I will call "the pumping centre" http://tinypic.com/r/295cry8/8 in the airing cupboard: a very short hiss, then (clear) water * Taking my courage in both hands, since I have always feared that this would cause an explosive leak of water, I took off the pump bleed screw - nothing came out; I then turned the impeller with screwdriver - free. * Set the room thermostat set to 18 (normal for us). * Switched OFF the water heating, so that it was out of the equation. * Switched on the system: everything fired up. The boiler was in what I would call "boost phase": I could hear the flames roaring, and the plume was shooting out of the condenser pipe outside. * Inside a minute the boiler reached a temp of c.65 degrees, then switched off, boiler temp dropped to about 25, then it switched on again, boosted to 65, off again -- continued with this cycle -- I left off keeping an eye on it after about 15 mins. * After the first "boost" from the boiler, I had returned to the pump, removed the bleed screw again and checked if the impeller was turning - it was whizzing round; a fairly light touch with a screwdriver did not stop it. * About an hour later the room thermostat hit the set temp of 18, and everything switched off; by this time the boiler seemed to be burning fairly continuously, quietly, at about 65, with a gentle plume from the condenser pipe. * None of the radiators ever got "hot" as such - just steadily warmer. (I expect them to get hot, and thus bring up the room temperature more quickly than the over-an-hour that it took.) * The bypass seemed to be working: the pipe TO the bypass was hot, but the pipe FROM it was cold. This says it was not operating. If in bypass mode both pipes either side of the valve would be hot. This suggests no blockage. * Finally: the pump was making its [to me, usual, and unacceptable] humming noise, and occasionally a distinct "rushing", or rather *scuttering*, noise, which must surely indicate air ... but I do not know how to remove that from the system, as I have bled all radiators, as well as the screws in the pumping centre. Later today I switched the water heating ON again, to see what would happen. This seemed to confuse things, although I can't be precise about how. So I am now suspecting the 3-way valve.... but this wouldn't explain the overall problem which kicked the whole thing off, which is that the system seems to take a long time to heat up, if at all, the boiler failing with a Fault Code (indicating "Circulation Fault"), the year-old vibration noise in the whole system, etc etc etc. What are the pipe temperatures around the diverting valve? In theory the vertical pipe should be hot, and one branch hot and the other cold. I still suspect the pump. If I was in your shoes I would have the HW timer set to off and the hot water cylinder cold, or at least cold for the bottom half by running off a load of hot water. I would then set HW timer to on and CH off such that the boiler fired up only for HW. I would then check the primary pipes in and the pipe out of your hot water cylinder, monitoring temperatures. I would expect the output (lower) pipe to get fairly warm after a few minutes. If the top pipe is burning hot only after a long while of the boiler firing and the lower cold, then I would suspect the pump and remove it to check. Looks like I'm going to have to (a) find a heating engineer who will look at it and (b) pay him to do what I (with the vast amounts of help I've received here) have been doing ... buggering about looking for the problem. Except the heating engineer will probably simply replace one thing after another until it seems fixed, and then present me with the aggregated bill ... hence why we [try to] DIY! Thanks for all the help, everyone! John I would say the pump is still a likely failure candidate! The fact it runs is one thing, but I'm left wondering if the impeller is intact. I would expect to get whooshing and other circulating noises from connected pipework when the pump is running, especially on the highest speed. |
Central heating system conundrum
Fred -- thanks a lot for your input :)
* The bypass seemed to be working: the pipe TO the bypass was hot, but the pipe FROM it was cold. This says it was not operating. If in bypass mode both pipes either side of the valve would be hot. This suggests no blockage. I think we agree: What I meant was: it was "functioning correctly" rather than "operating", in that it had not opened ... which it shouldn't if the system has no blockage, as you have said. What are the pipe temperatures around the diverting valve? In theory the vertical pipe should be hot, and one branch hot and the other cold. Yes - this is all as expected and as you describe. I still suspect the pump.... [rest of your post deleted for brevity] Well I'm glad to hear that! A simple swop-out would be a nice solution, although I think I'd still get a professional to do it. Thanks for your post, which has much to ponder, and encourages me. Meanwhile we are managing well: ambient temperatures are easily bearable (even here in the NE, with this sudden dip in the weather), and the immersion heater is great![1] John [1] We have almost never used it in the 30 years we've been in this house. However with just the two if us now, and both mean buggers, we are finding that it gives us ample hot water ... which has never been so hot, with the CH system! |
Central heating system conundrum
On 25/04/2015 11:53, Another John wrote:
Fred -- thanks a lot for your input :) * The bypass seemed to be working: the pipe TO the bypass was hot, but the pipe FROM it was cold. This says it was not operating. If in bypass mode both pipes either side of the valve would be hot. This suggests no blockage. I think we agree: What I meant was: it was "functioning correctly" rather than "operating", in that it had not opened ... which it shouldn't if the system has no blockage, as you have said. What are the pipe temperatures around the diverting valve? In theory the vertical pipe should be hot, and one branch hot and the other cold. Yes - this is all as expected and as you describe. I still suspect the pump.... [rest of your post deleted for brevity] Well I'm glad to hear that! A simple swop-out would be a nice solution, although I think I'd still get a professional to do it. Thanks for your post, which has much to ponder, and encourages me. Meanwhile we are managing well: ambient temperatures are easily bearable (even here in the NE, with this sudden dip in the weather), and the immersion heater is great![1] John [1] We have almost never used it in the 30 years we've been in this house. However with just the two if us now, and both mean buggers, we are finding that it gives us ample hot water ... which has never been so hot, with the CH system! The cylinder stat can be turned up if its important! As you might gather this is a DIY group, given the cost of a heating engineer and his markup on any items he fits, it's difficult to understand why you would want to get a man in! His cost can pay for a lot of tools you get to keep. Its the right time of the year to work on a CH systems where it can be left part finished for a week or so, and you can always get guidance and help here. |
Central heating system conundrum
On 25/04/2015 11:53, Another John wrote:
[1] We have almost never used it in the 30 years we've been in this house. However with just the two if us now, and both mean buggers, we are finding that it gives us ample hot water ... which has never been so hot, with the CH system! It's good to have an immersion heater as a standby but, with the relative price of electricity vs gas, it's much cheaper to use gas (when it works!). -- Cheers, Roger ____________ Please reply to Newsgroup. Whilst email address is valid, it is seldom checked. |
Central heating system conundrum
On Sat, 25 Apr 2015 12:06:26 +0100, Fredxxx wrote:
As you might gather this is a DIY group, given the cost of a heating engineer and his markup on any items he fits, it's difficult to understand why you would want to get a man in! His cost can pay for a lot of tools you get to keep. Its the right time of the year to work on a CH systems ... Last week yes, but not now. Gritters out an about spreading salt this evening and it's 1.4 C air temp outside as I type. Whilst I'm inclined to agree I'm not sure a "simple" CH pump swap is a good thing to start with. In theory you just close the valves, undo the two flanges, slide the old pump out, slide the new in with new rubber washers, tighten the flanges, open the valves, bleed pump, run system for a bit, bleed pump again. No more than an 30 mins... But as has been detailed before in this thread it's highly unlikely to be that easy and simple. -- Cheers Dave. |
Central heating system conundrum
In article o.uk,
"Dave Liquorice" wrote: .... Whilst I'm inclined to agree I'm not sure a "simple" CH pump swap is a good thing to start with. In theory you just close the valves, ... ... No more than 30 mins... But as has been detailed before in this thread it's highly unlikely to be that easy and simple. Aye -- I have bitter experience in the past, especially with anything involving plumbing, of spending a week doing "a day's" job, and progressively going off to get more bits, and making a right mess of the plumbing into the bargain. With the result that these days I'm very chary of plumbing, and especially something as fundamental, and sophisticated, as a CH system. My seeking advice here has been based on (a) was it summat simple that I *could*, in fact, fix myself? (e.g. "drain and refill the system" (not that simple, in itself!)) (b) what is it likely to be? (c) to **understand** how things work: I do NOT just like to have things fixed, I like to understand why they broke and how they have been fixed. The great principle in DIY is that you fix something by carefully taking it apart, finding what's wrong, and then fixing/replacing it. Then you have learned an awful lot. You cannot "take apart " a CH system to fix it in the same way that you fix a vacuum cleaner, or even a car engine [in the old days!]. So anyway - thanks Boys, again, SO much: I will report back when the job is finally done! John |
Central heating system conundrum
On Sun, 26 Apr 2015 11:29:57 +0100, Another John wrote:
But as has been detailed before in this thread it's highly unlikely to be that easy and simple. Aye -- I have bitter experience in the past, especially with anything involving plumbing, of spending a week doing "a day's" job, and progressively going off to get more bits, and making a right mess of the plumbing into the bargain. Ah but you were finding out and learning about all the gotchas as you went along. With the pump you know from the experience of others that it might be simpler to just drain down, cut the pipe work and fit new pipe stubs, new (ball) valves, new rubber washers and new pump. If I was faced with this problem I'd get all the bits required to complete the cut the pipework method, checking that the valves could be returned for a refund if not used. Then see if the the pump flanges will come undone. If they both move, see if the (gate) valves feel as if they have decently closed, fully open and close them, hard, several times to try and get any scale off, cautiously proceed to remove the pump with plenty of old towels about to catch any spillage. Judging how well the valves have shut by how much water continues to appear after the initial spill. Failure at any of the steps would trigger an abort to the drain down/cut pipes method but you aren't committed to doing that at that time, just tighten what has been loosened and prepare for the bigger operation. The desire to know how and why things work and ways to fix 'em should be nurtured not smothered or rejected by the odd disappointment or "bad job". -- Cheers Dave. |
Central heating system conundrum
Roger Mills wrote :
Pumps should hopefully last longer than that - but may not. I can only remember replacing mine 3 times in 38 years - and in two of those cases the pump hadn't failed but was changed for other reasons. First pump lasted 30 years, replacent because new boiler was fitted 6 years ago. Current pump is 6 years old. -- Regards, Harry (M1BYT) (L) http://www.ukradioamateur.co.uk |
Central heating system conundrum
In message , charles
writes In article , Harry Bloomfield wrote: Roger Mills wrote : Pumps should hopefully last longer than that - but may not. I can only remember replacing mine 3 times in 38 years - and in two of those cases the pump hadn't failed but was changed for other reasons. First pump lasted 30 years, replacent because new boiler was fitted 6 years ago. Current pump is 6 years old. My pump was installed, by me, in 1988. Pump in my late parents house was installed in about 1965 and failed within a year, the replacement is still running! It is slightly more robust than the average domestic pump, but even so quite amazing. Damn, that's jinxed it............ -- Bill |
Central heating system conundrum
In message , Bill
writes In message , charles writes In article , Harry Bloomfield wrote: Roger Mills wrote : Pumps should hopefully last longer than that - but may not. I can only remember replacing mine 3 times in 38 years - and in two of those cases the pump hadn't failed but was changed for other reasons. First pump lasted 30 years, replacent because new boiler was fitted 6 years ago. Current pump is 6 years old. My pump was installed, by me, in 1988. Pump in my late parents house was installed in about 1965 and failed within a year, the replacement is still running! It is slightly more robust than the average domestic pump, but even so quite amazing. I don't know, but AFAICT the CH system here was probably installed in the 1970's, though maybe the late '60's. It looks like it still has the original pump - a large and sturdy Grundfos -- Chris French |
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