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UK diy (uk.d-i-y) For the discussion of all topics related to diy (do-it-yourself) in the UK. All levels of experience and proficency are welcome to join in to ask questions or offer solutions. |
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#1
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Combi Boiler loosing pressure. PRV?
Got an C&M Britony boiler that has been loosing pressure for a while.
It appears that the pressure release valve drips to the overflow releasing the pressure over time, or suddently gives way (say at 2 bar) and drops the pressure. So far I have lived with this, and just topped up as required. However! yesterday a leak started within the boiler, after examination the leak has been progressive (i.e substantial limescale etc) and therefore been leaking over time from the "air seperator". The leak is to the extent that any water in the system is lost. Obviously the air seperator needs replacing (cost about £25.00), would it it wise to replace the pressure release valve at the same time? |
#2
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"Sam" wrote in message ... Got an C&M Britony boiler that has been loosing pressure for a while. It appears that the pressure release valve drips to the overflow releasing the pressure over time, or suddently gives way (say at 2 bar) and drops the pressure. So far I have lived with this, and just topped up as required. However! yesterday a leak started within the boiler, after examination the leak has been progressive (i.e substantial limescale etc) and therefore been leaking over time from the "air seperator". The leak is to the extent that any water in the system is lost. Obviously the air seperator needs replacing (cost about £25.00), would it it wise to replace the pressure release valve at the same time? I've had two boilers, and the pressure release valve was set to 2.4bar on one, and 3bar on the other. It might actually say on the valve if you have a look. 2 bar seems a little low to me for an overpressure valve, on the other hand 2 bar seems a slightly high pressure to run a CH system at. Can you test the overpressure valve by filling the CH loop until the overpressure valve blows off: I presume you have a pressure guage on your combi. Also, what is the pressure of your boiler when cold, and what does it climb to when it fires up the CH? There are other faults that could cause your overpressure release valve to appear to be acting up. It should not drip water out of the overflow if the pressure is below its calibrated operating point though. Andy. |
#3
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On Tue, 14 Jun 2005 12:36:31 +0000, Sam wrote:
Got an C&M Britony boiler that has been loosing pressure for a while. It appears that the pressure release valve drips to the overflow releasing the pressure over time, or suddently gives way (say at 2 bar) and drops the pressure. So far I have lived with this, and just topped up as required. However! yesterday a leak started within the boiler, after examination the leak has been progressive (i.e substantial limescale etc) and therefore been leaking over time from the "air seperator". The leak is to the extent that any water in the system is lost. Obviously the air seperator needs replacing (cost about £25.00), would it it wise to replace the pressure release valve at the same time? The SealedCH Faq may help you. -- Ed Sirett - Property maintainer and registered gas fitter. The FAQ for uk.diy is at http://www.diyfaq.org.uk Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html |
#4
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Can you test the overpressure valve by filling the CH loop until the
overpressure valve blows off: I presume you have a pressure guage on your combi. Also, what is the pressure of your boiler when cold, and what does it climb to when it fires up the CH? Operates at about 3bar, but "drips" virtually continously till pressure get down to 0. When refilled, usually take it to 1 bar, when operating (hot) may reach 1.5-2bar. |
#5
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When refilled, usually take it to 1 bar, when operating (hot) may reach
1.5-2bar. If it is reaching 2 bar when operating, I'd consider adding an additional expansion vessel. Christian. |
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