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"

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]

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.

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.

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

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!?

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]

In article ,
(Andrew Gabriel) wrote:

In article ],
Another John writes:
... It was installed in 2008 when the system was renovated; it
is in a *vertical* orientation, ....

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.

Hmmmmmmmm !!! Must check on that then. Like I said before, the
installers were (still are) one of the best respected firms in our area.
Hmmmmm

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.

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.

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

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

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

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