The otter Posted February 25, 2008 Share Posted February 25, 2008 (edited) My boiler drops in pressure after every time it is in use. I'm constantly having to top it up and i've noticed that water is coming out of the pipe to the exterior of my house. Any ideas what the problem might be and how much it could be to fix. Any help appreciated Thanks Edited October 20, 2020 by nikki-red Link to comment Share on other sites More sharing options...
neeeeeeeeeek Posted February 25, 2008 Share Posted February 25, 2008 I had that, some valve or diaphram needed replacing. It was not that expensive but you need a Corgi registered plumber. Link to comment Share on other sites More sharing options...
rad Posted February 25, 2008 Share Posted February 25, 2008 There may be a leak in the systemm - I'm having that problem right now. Link to comment Share on other sites More sharing options...
neeeeeeeeeek Posted February 25, 2008 Share Posted February 25, 2008 It won't be a leak if it's coming out the pipe at the back as that's where it's supposed to come out. Link to comment Share on other sites More sharing options...
Complete-Heat Posted February 25, 2008 Share Posted February 25, 2008 Maybe the filling loop is bypassing. Easy way to check is to fill the system to 1.5 bar and then disconnect it. If you not happy to do this then fill to 1.5 bar but DONT use either hot water or heating for 6-12 hours. If you see the pressure valve rising then filling loop is the culprit. HOWEVER, more than likely the expansion vessel has either lost pressure or the expansion pipe is blocked. This causes the pressure to rise (when the heating is on) to above 2.5bar and the safety PRV kicks in - hence noticing water outside. You will also need the PRV replacing Link to comment Share on other sites More sharing options...
Complete-Heat Posted February 25, 2008 Share Posted February 25, 2008 It won't be a leak if it's coming out the pipe at the back as that's where it's supposed to come out. That pipe should always be dry unless the boiler has a problem. Its linked to the safety pressure release valve. Link to comment Share on other sites More sharing options...
neeeeeeeeeek Posted February 25, 2008 Share Posted February 25, 2008 Sorry, I was not very clear. I did not mean all the time, just when there is something wrong! it's what happended to mine. Link to comment Share on other sites More sharing options...
The otter Posted February 25, 2008 Author Share Posted February 25, 2008 Maybe the filling loop is bypassing. Easy way to check is to fill the system to 1.5 bar and then disconnect it. If you not happy to do this then fill to 1.5 bar but DONT use either hot water or heating for 6-12 hours. If you see the pressure valve rising then filling loop is the culprit. HOWEVER, more than likely the expansion vessel has either lost pressure or the expansion pipe is blocked. This causes the pressure to rise (when the heating is on) to above 2.5bar and the safety PRV kicks in - hence noticing water outside. You will also need the PRV replacing This sounds like the problem. How much is that to be fixed approximately Link to comment Share on other sites More sharing options...
Complete-Heat Posted February 25, 2008 Share Posted February 25, 2008 [/u][/b] This sounds like the problem. How much is that to be fixed approximately Need to know make and model of the boiler first. On some boilers you cant get to the expansion vessel (unless you remove the boiler from the wall). Therefore you 'tie' a new vessel into the existing system. Also gotta drain down. Again some boilers have quality isolation valves on the flow/return AND a drain off internally which makes for a quicker job. Unfortunatley most do not You also need a new 3bar PRV fitting as the old one will continue to leak. Link to comment Share on other sites More sharing options...
Guest pegmosaic Posted February 26, 2008 Share Posted February 26, 2008 mine did that, I had a leak under a tiles floor!! :-( Link to comment Share on other sites More sharing options...
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