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#1
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Tracing tiny leaks in sealed system
Okay, several months down the line I'm getting sick of filling up and
diluting the additive in my combi system. New combi boiler in the summer, changed from vented to sealed, fair bit of old pipework and rads. All the rad valves are new at various times within the last 8 years. I'm guessing there are leaks at the new pressure though nothing is visible and upstairs pipework is concealed. I suppose the leaks are so tiny that the water evaporates on the surface making it harder to trace. Maybe when the rads aren't on come the spring it will be more obvious. Any one know how I can track down the source? -- Mike W |
#2
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Tracing tiny leaks in sealed system
"visionset" wrote in message ... Okay, several months down the line I'm getting sick of filling up and diluting the additive in my combi system. New combi boiler in the summer, changed from vented to sealed, fair bit of old pipework and rads. All the rad valves are new at various times within the last 8 years. I'm guessing there are leaks at the new pressure though nothing is visible and upstairs pipework is concealed. I suppose the leaks are so tiny that the water evaporates on the surface making it harder to trace. Maybe when the rads aren't on come the spring it will be more obvious. Any one know how I can track down the source? -- Mike W Just a thought - is the pressure much higher than an open vented system with a tank in the loft? Thinking of changing mine and wondered if some of the radiators would be at risk. |
#3
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Tracing tiny leaks in sealed system
On Fri, 16 Feb 2007 15:12:28 GMT, "John"
wrote: |! |!"visionset" wrote in message ... |! Okay, several months down the line I'm getting sick of filling up and |! diluting the additive in my combi system. |! New combi boiler in the summer, changed from vented to sealed, fair bit of |! old pipework and rads. All the rad valves are new at various times within |! the last 8 years. I'm guessing there are leaks at the new pressure though |! nothing is visible and upstairs pipework is concealed. I suppose the |! leaks are so tiny that the water evaporates on the surface making it |! harder to trace. Maybe when the rads aren't on come the spring it will be |! more obvious. Any one know how I can track down the source? |! |! -- |! Mike W |! |! |!Just a thought - is the pressure much higher than an open vented system with |!a tank in the loft? Yes pressure goes up from less than a bar to 1-2.5 Bar |!Thinking of changing mine and wondered if some of the radiators would be at |!risk. Only if they are very corroded. I used inhibitor in my radiators with the vented system and despite having to flush out a lot of black crud, the old radiators are fine. -- Dave Fawthrop dave hyphenologist co uk 20,000 free e-books at Project Gutenberg! http://www.gutenberg.org For Yorkshire Dialect go to www.hyphenologist.co.uk/songs/ http://www.gutenberg.org/author/John_Hartley http://www.gutenberg.org/author/F_W_Moorman |
#4
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Tracing tiny leaks in sealed system
"John" wrote in message ... Just a thought - is the pressure much higher than an open vented system with a tank in the loft? Thinking of changing mine and wondered if some of the radiators would be at risk. Yes 2 to 3 times. You hijack my thread why don't you ;-) My experience leaves me dubious about combis (if that's what you're planning) There is one heck of a lot to be said for keeping things simple. Despite appearances a Combi system is much more complex, and hence expensive, more likely to go tits up and more expensive when it does. Suits my house, but never again. I'd say the only place for a combi is a new build or complete renno (inc 1st fix wets) with 1 bathroom. Does a sealant additive do what it says on the tin? -- Mike W |
#5
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Tracing tiny leaks in sealed system
visionset wrote:
Okay, several months down the line I'm getting sick of filling up and diluting the additive in my combi system. If this was a high vacuum system, I'd pump it down, connect a mass-spectrometer, then spray helium round any suspect pipe areas. When you get a spike of helium coming through the mass spec, you've found a leak. Unfortunately, this is probably not practical, unless you happen to have a source of high vacuum, a mass spectrometer, and some way to bake out the existing water in the piping. |
#6
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Tracing tiny leaks in sealed system
"Ian Stirling" wrote in message ... visionset wrote: Okay, several months down the line I'm getting sick of filling up and diluting the additive in my combi system. If this was a high vacuum system, I'd pump it down, connect a mass-spectrometer, then spray helium round any suspect pipe areas. When you get a spike of helium coming through the mass spec, you've found a leak. Unfortunately, this is probably not practical, unless you happen to have a source of high vacuum, a mass spectrometer, and some way to bake out the existing water in the piping. In my previous career as an analytical chemist I could of at least borrowed a pump and sampled a makeshift port and taken in the sample to work. As a programmer I can't think of any software I could write to help me! -- Mike W |
#7
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Tracing tiny leaks in sealed system
Ian Stirling wrote:
visionset wrote: Okay, several months down the line I'm getting sick of filling up and diluting the additive in my combi system. If this was a high vacuum system, I'd pump it down, connect a mass-spectrometer, then spray helium round any suspect pipe areas. When you get a spike of helium coming through the mass spec, you've found a leak. Try adding a UV dye to the water, turn the lights out and go hunting with a UV torch. http://www.accepta.com/uv_leak_detector.asp I wonder if the stuff sold for PC modders would be OK http://www.wc101.com/reviews/uv-dye-green/ -- Adrian C |
#8
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Tracing tiny leaks in sealed system
Adrian C wrote:
Ian Stirling wrote: visionset wrote: Okay, several months down the line I'm getting sick of filling up and diluting the additive in my combi system. If this was a high vacuum system, I'd pump it down, connect a mass-spectrometer, then spray helium round any suspect pipe areas. When you get a spike of helium coming through the mass spec, you've found a leak. Try adding a UV dye to the water, turn the lights out and go hunting with a UV torch. Or something really stinky. Ex-chemists should be good at this. |
#9
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Tracing tiny leaks in sealed system
In message , visionset
writes Okay, several months down the line I'm getting sick of filling up and diluting the additive in my combi system. New combi boiler in the summer, changed from vented to sealed, fair bit of old pipework and rads. All the rad valves are new at various times within the last 8 years. I'm guessing there are leaks at the new pressure though nothing is visible and upstairs pipework is concealed. I suppose the leaks are so tiny that the water evaporates on the surface making it harder to trace. Maybe when the rads aren't on come the spring it will be more obvious. Any one know how I can track down the source? Some kind of UV sensitive dye? Buy a forged note detector light, wait until dark then follow pipework looking for glowing patches. -- Clint Sharp |
#10
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Tracing tiny leaks in sealed system
In message , visionset
writes In my previous career as an analytical chemist I could of at least borrowed a pump and sampled a makeshift port and taken in the sample to work. As a programmer I can't think of any software I could write to help me! Not surprised, it's a hardware problem. For a change. -- Clint Sharp |
#11
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Tracing tiny leaks in sealed system
My bet would be, as someone said above, the pressure relief valve which
normally vents outside the house. In my experience once they have lifted in anger they seldom re-seat. Not expensive or difficult to replace, just make sure you get the right gender on the inlet and outlet. |
#12
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Tracing tiny leaks in sealed system
On 16 Feb, 14:57, "visionset" wrote:
Okay, several months down the line I'm getting sick of filling up and diluting the additive in my combi system. New combi boiler in the summer, changed from vented to sealed, fair bit of old pipework and rads. All the rad valves are new at various times within the last 8 years. I'm guessing there are leaks at the new pressure though nothing is visible and upstairs pipework is concealed. I suppose the leaks are so tiny that the water evaporates on the surface making it harder to trace. Maybe when the rads aren't on come the spring it will be more obvious. Any one know how I can track down the source? -- Mike W Drain the system then connect a car footpump and check with soapy water at all the joints? |
#13
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Tracing tiny leaks in sealed system
visionset wrote:
Okay, several months down the line I'm getting sick of filling up and diluting the additive in my combi system. New combi boiler in the summer, changed from vented to sealed, fair bit of old pipework and rads. All the rad valves are new at various times within the last 8 years. I'm guessing there are leaks at the new pressure though nothing is visible and upstairs pipework is concealed. I suppose the leaks are so tiny that the water evaporates on the surface making it harder to trace. Maybe when the rads aren't on come the spring it will be more obvious. Any one know how I can track down the source? Is it possible to put a food dye, or even better a fluorescent dye into the system, turn down the temperature and leave it for a few hours pumping water throughout the system by making heating and water demands? My thoughts are that by reducing the temperature, you will loosen any slack joint and enable it to leak slightly. Then go over the pipe work looking for the dye/fluorescent marker. (A fluorescent black light does not cost all that much. See Maplins site.) After you find/don't find any leak, flush the system out and use as normal. I could be wrong, but I hope this helps. Dave |
#14
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Tracing tiny leaks in sealed system
visionset wrote:
My experience leaves me dubious about combis (if that's what you're planning) There is one heck of a lot to be said for keeping things simple. Despite appearances a Combi system is much more complex, and hence You seem to be confusing sealed systems with combis. Most boilers these days use a sealed primary, not just the combis. -- Cheers, John. /================================================== ===============\ | Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------| | John Rumm - john(at)internode(dot)co(dot)uk | \================================================= ================/ |
#15
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Tracing tiny leaks in sealed system
Newshound wrote:
My bet would be, as someone said above, the pressure relief valve which normally vents outside the house. In my experience once they have lifted in anger they seldom re-seat. Not expensive or difficult to replace, just make sure you get the right gender on the inlet and outlet. Tie a clear plastic sandwich bag round the outlet and see. If there is a leak the bag will accumulate water. -- Cheers, John. /================================================== ===============\ | Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------| | John Rumm - john(at)internode(dot)co(dot)uk | \================================================= ================/ |
#16
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Tracing tiny leaks in sealed system
On Fri, 16 Feb 2007 14:57:16 +0000, visionset wrote:
Okay, several months down the line I'm getting sick of filling up and diluting the additive in my combi system. New combi boiler in the summer, changed from vented to sealed, fair bit of old pipework and rads. All the rad valves are new at various times within the last 8 years. I'm guessing there are leaks at the new pressure though nothing is visible and upstairs pipework is concealed. I suppose the leaks are so tiny that the water evaporates on the surface making it harder to trace. Maybe when the rads aren't on come the spring it will be more obvious. Any one know how I can track down the source? If you've eliminated the PRD and are sure it really is a leak in the pipework then go round all the rad joints feeling for damp. If you're having to top up several times a year you may well feel dampness from the leak even if it tends to evaporate before it can accumulate and drip off visibly. Obviously test joints to the boiler and elsewhere also. Compression joints are the main culprits here. |
#17
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Tracing tiny leaks in sealed system
In article ,
"visionset" writes: Okay, several months down the line I'm getting sick of filling up and diluting the additive in my combi system. New combi boiler in the summer, changed from vented to sealed, fair bit of old pipework and rads. All the rad valves are new at various times within the last 8 years. I'm guessing there are leaks at the new pressure though nothing is visible and upstairs pipework is concealed. I suppose the leaks are so tiny that the water evaporates on the surface making it harder to trace. Maybe when the rads aren't on come the spring it will be more obvious. Any one know how I can track down the source? As you suggest, doing it when system is cold makes it much more likely you will see the leak. Trouble is the pressure will also be lower, leak may reduce or stop, so increase the pressure up to the normal pressure when hot (system all turned off, obviously). Then go around a few hours later checking all the pipework, rads, etc for leaks. I installed a new system 5 years ago, and I've had two of the rubber O-rings on radiator blanking plugs fail, which I tracked this way. The leak wasn't enough that I needed to top it up, but it annoyed me there was any leak at all. Other places to check are the pipework inside the boiler casing, and hardest of all, a leak in a condensing heat exchanger, because you can't usually get to it. Check PRV isn't leaking. To let the pressure down to normal afterwards, draw off water from a radiator bleed valve or drain valve. Don't use the pressure relief value as you can end up with debris stuck in it which makes it leak. -- Andrew Gabriel [email address is not usable -- followup in the newsgroup] |
#18
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Tracing tiny leaks in sealed system
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#19
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Tracing tiny leaks in sealed system
In article ,
wrote: Remember to take the plastic tops of rad valves & TRVs and check for signs of leakage around the spindle , seepage can evaporate away before showing up on the visible body of the valve. Robert To check rad valve spindles for leakage wrap a tissue around each one. The tissue may not be damp at time of checking but will generally show a telltale stain, left behind from water that has evaporated. -- Tony Williams. |
#20
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Tracing tiny leaks in sealed system
Tony Williams wrote:
In article , wrote: Remember to take the plastic tops of rad valves & TRVs and check for signs of leakage around the spindle , seepage can evaporate away before showing up on the visible body of the valve. Robert To check rad valve spindles for leakage wrap a tissue around each one. The tissue may not be damp at time of checking but will generally show a telltale stain, left behind from water that has evaporated. And if the valve is wet, a light blue tissue will show it up better than a white one. Dave |
#21
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Tracing tiny leaks in sealed system
Dave wrote:
Tony Williams wrote: In article , wrote: Remember to take the plastic tops of rad valves & TRVs and check for signs of leakage around the spindle , seepage can evaporate away before showing up on the visible body of the valve. Robert To check rad valve spindles for leakage wrap a tissue around each one. The tissue may not be damp at time of checking but will generally show a telltale stain, left behind from water that has evaporated. And if the valve is wet, a light blue tissue will show it up better than a white one. Toilet paper - especially cheap stuff, will shrink and crumple when it gets a spot of water on it. |
#22
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Tracing tiny leaks in sealed system
Ian Stirling wrote:
Dave wrote: Tony Williams wrote: In article , wrote: Remember to take the plastic tops of rad valves & TRVs and check for signs of leakage around the spindle , seepage can evaporate away before showing up on the visible body of the valve. Robert To check rad valve spindles for leakage wrap a tissue around each one. The tissue may not be damp at time of checking but will generally show a telltale stain, left behind from water that has evaporated. And if the valve is wet, a light blue tissue will show it up better than a white one. Toilet paper - especially cheap stuff, will shrink and crumple when it gets a spot of water on it. That will because it is designed to dissolve in water. Dave |
#23
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Tracing tiny leaks in sealed system
"visionset" wrote in message ... Okay, okay, okay, but what of the Fernox Leak Sealer additive, anyone used it? Does it do what it says? -- Mike W |
#24
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Tracing tiny leaks in sealed system
In article ,
Dave wrote: Ian Stirling wrote: Toilet paper - especially cheap stuff, will shrink and crumple when it gets a spot of water on it. That will because it is designed to dissolve in water. Arrgh! Memories of Bronco bogpaper. As scratchy as hell, and probably even aqua regea wouldn't dissolve it. -- Tony Williams. |
#25
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Tracing tiny leaks in sealed system
Sorry to resurrect this one but I am hoping someone could shed some light on my current problem.
I have a seal combi. The pressure drops down to zero within 20 minutes of the ch going off. I fill it and we start again. The previous tenant kept the system alive by having the fill valve constantly open, not good. Now. I do have a leaky DHW Heat Exchanger which will fill a cup in a day. Is this enough to explain the dramatic drops in pressure on the system ? Thanks in advance if anyone is still around... |
#26
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Tracing tiny leaks in sealed system
wrote:
Sorry to resurrect this one but I am hoping someone could shed some light on my current problem. I have a seal combi. The pressure drops down to zero within 20 minutes of the ch going off. I fill it and we start again. The previous tenant kept the system alive by having the fill valve constantly open, not good. Now. I do have a leaky DHW Heat Exchanger which will fill a cup in a day. Is this enough to explain the dramatic drops in pressure on the system ? Thanks in advance if anyone is still around... Sounds like it might be your expansion vessel, try topping the system up to 1 bar when cold, then fire it up and watch the pressure gauge, if it hits 3 then the pressure relief valve will dump water out. -- Toby... remove pants to reply |
#27
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Tracing tiny leaks in sealed system
On 09/12/2012 14:12, Toby wrote:
wrote: Sorry to resurrect this one but I am hoping someone could shed some light on my current problem. I have a seal combi. The pressure drops down to zero within 20 minutes of the ch going off. I fill it and we start again. The previous tenant kept the system alive by having the fill valve constantly open, not good. Now. I do have a leaky DHW Heat Exchanger which will fill a cup in a day. Is this enough to explain the dramatic drops in pressure on the system ? Thanks in advance if anyone is still around... Sounds like it might be your expansion vessel, try topping the system up to 1 bar when cold, then fire it up and watch the pressure gauge, if it hits 3 then the pressure relief valve will dump water out. +1 -- Cheers, Roger ____________ Please reply to Newsgroup. Whilst email address is valid, it is seldom checked. |
#28
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Tracing tiny leaks in sealed system
On Sunday, December 9, 2012 2:12:49 PM UTC, Toby wrote:
brian wrote: Sorry to resurrect this one but I am hoping someone could shed some light on my current problem. I have a seal combi. The pressure drops down to zero within 20 minutes of the ch going off. I fill it and we start again. The previous tenant kept the system alive by having the fill valve constantly open, not good. Now. I do have a leaky DHW Heat Exchanger which will fill a cup in a day. Is this enough to explain the dramatic drops in pressure on the system ? Thanks in advance if anyone is still around... Sounds like it might be your expansion vessel, try topping the system up to 1 bar when cold, then fire it up and watch the pressure gauge, if it hits 3 then the pressure relief valve will dump water out. -- Toby... remove pants to reply Hi Toby Thanks for replying. I filled to 1 and it went hurtling up to 3. Then when the heating went orf it went back down to below 1 Thoughts ? Brian |
#30
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Tracing tiny leaks in sealed system
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#31
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Tracing tiny leaks in sealed system
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#32
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Tracing tiny leaks in sealed system
Cheers chaps, off I go to get a foot pump with a good guage on it. I will have to replace the DHW exhanger as its leaking anyway. I will let you know how it goes.....
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#33
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Tracing tiny leaks in sealed system
On 09/12/2012 15:44, wrote:
On Sunday, December 9, 2012 2:12:49 PM UTC, Toby wrote: Sounds like it might be your expansion vessel, try topping the system up to 1 bar when cold, then fire it up and watch the pressure gauge, if it hits 3 then the pressure relief valve will dump water out. -- Toby... remove pants to reply Hi Toby Thanks for replying. I filled to 1 and it went hurtling up to 3. Then when the heating went orf it went back down to below 1 Thoughts ? Brian As others have already said, yes, it is the expansion vessel that is at fault here, if I were you, I would firstly press the centre part of the valve (Schrader valve, like you have on a car) and see what happens. If you get air or nothing coming out, this is good, simply pump it up to 0.7 bar (10-11PSI) but do this with your system de pressurised - if when you pump it up, you see the pressure reading on the boiler rise from 0, then you need to let some water out of the system and then top it up again - keep doing this until you have it at 0.7 bar, and 0 on the boiler pressure gauge. If, on the other hand, the Schrader valve lets out water when you press it, then the vessel will need replacing - you can either replace like for like, or you can just add another one to the system where convenient, leaving the failed one connected (assuming it isn't leaking!). - this is the best course of action if it is not easily replaced (some boilers have the buried at the back, that required stripping the boiler down to get to it, and some are just expensive compared to a generic one. An external one will look something like this, often seen in bright red too. http://thumbs4.ebaystatic.com/d/l225...UBLaBkQArQ.jpg If you don't have one of these, then it is probably in the boiler, so post the make and model if you cant see it in there! -- Toby... Remove pants to reply |
#34
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Tracing tiny leaks in sealed system
On 09/12/2012 22:49, Toby wrote:
If, on the other hand, the Schrader valve lets out water when you press it, then the vessel will need replacing - you can either replace like for like, or you can just add another one to the system where convenient, leaving the failed one connected (assuming it isn't leaking!). If the schraeder valve is leaking you may be able to do something with a metal valve cap. Like these: http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogId_10151_productId_56 4273_langId_-1_categoryId_255241 AKA http://tinyurl.com/boaunkw Obviously you'll still need to fix the vessel. Andy |
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