Hi All,
Firstly, apologies for yet another thread about losing pressure in a CHS - I'm aware there are already a lot here as I've read most of them!
We've been having problems with our Worcester 24i Junior boiler losing pressure for some time, and I've done a lot of troubleshooting to try and diagnose the issue. We have British Gas Home care, who have been out several times checking the boiler and they have replaced the PRV twice.
Now, here are the facts:
1) If I pressurise the system to ~1.2 bar, it will drop to 0 within a few hours, whether we turn the heating on or not.
2) If I isolate the boiler from the CHS by closing the inlet and outlet underneath the boiler, it will keep it's pressure. Before the PRV was replaced it would have still leaked but now the PRV seems to be ok. I can leave the boiler isolated for weeks and the hot water continues to work fine (thank god).
3) When I de-isolate (i.e. reopen the inlet and outlet) the CHS after a period of time, you hear the pressure being sucked out of the boiler, and the pressure immediately drops to 0.
4) I only need to open the tap on the filling loop for a second or two to lift the pressure from 0 all the way back up to 1.2, so clearly the volume of water being let back in is small.
5) I've checked all of the visible pipework, rad valves etc. for water and have found nothing.
6) I was unable to bleed many of the radiators for some time as they are old and the bleed valves have been worn down (and actually seemed too small to fit all of the brass keys I could find). I have bought every rad key I can find and now have a silver coloured one that actually works. Therefore I have now bled all rads on the system. Didn't make a difference.
7) When I fill the CHS and I turn the heating on, the wrong side of the none-return valve on the filling loop feels slightly warm. I also get a small amount of warm water through when I initially run the cold tap in the bathroom.
My assumptions:
- #2 suggests that the PRV is ok. I'm on the fifth floor and can't reach the PRV outlet so am unable to tie a bag/balloon over it to confirm, but I have never seen it dripping.
- #3 suggests that the problem/leak is in the system, rather than the boiler.
- #4 suggests that if there is a leak, it's above (in terms of altitude) the majority of the pipework/rads, as otherwise it would lose far more water/pressure than it appears to.
- #7 is a new discovery and makes me wonder whether the none-return valve is failing and letting water from the CHS back into the cold BUT even if this is the case, the tap at the other end of the filling loop is closed, so should prevent this from happening. Guess this could be caused by simple heat conduction.
My Questions:
- Are any of my assumptions wrong?
- Does anyone have any more steps I can use to troubleshoot the problem further?
- Does anyone know what my problem might be?
Apologies for the long post, but thought it worth spelling out everything I know or think I know as I'm at my wits end with this issue. Fortunately the hot water is fine.
Huge thanks in advance to anyone who can help us, we're first time home owners and this problem is stressful to the point we are tempted to sell the flat.
Cheers,
Bram
Firstly, apologies for yet another thread about losing pressure in a CHS - I'm aware there are already a lot here as I've read most of them!
We've been having problems with our Worcester 24i Junior boiler losing pressure for some time, and I've done a lot of troubleshooting to try and diagnose the issue. We have British Gas Home care, who have been out several times checking the boiler and they have replaced the PRV twice.
Now, here are the facts:
1) If I pressurise the system to ~1.2 bar, it will drop to 0 within a few hours, whether we turn the heating on or not.
2) If I isolate the boiler from the CHS by closing the inlet and outlet underneath the boiler, it will keep it's pressure. Before the PRV was replaced it would have still leaked but now the PRV seems to be ok. I can leave the boiler isolated for weeks and the hot water continues to work fine (thank god).
3) When I de-isolate (i.e. reopen the inlet and outlet) the CHS after a period of time, you hear the pressure being sucked out of the boiler, and the pressure immediately drops to 0.
4) I only need to open the tap on the filling loop for a second or two to lift the pressure from 0 all the way back up to 1.2, so clearly the volume of water being let back in is small.
5) I've checked all of the visible pipework, rad valves etc. for water and have found nothing.
6) I was unable to bleed many of the radiators for some time as they are old and the bleed valves have been worn down (and actually seemed too small to fit all of the brass keys I could find). I have bought every rad key I can find and now have a silver coloured one that actually works. Therefore I have now bled all rads on the system. Didn't make a difference.
7) When I fill the CHS and I turn the heating on, the wrong side of the none-return valve on the filling loop feels slightly warm. I also get a small amount of warm water through when I initially run the cold tap in the bathroom.
My assumptions:
- #2 suggests that the PRV is ok. I'm on the fifth floor and can't reach the PRV outlet so am unable to tie a bag/balloon over it to confirm, but I have never seen it dripping.
- #3 suggests that the problem/leak is in the system, rather than the boiler.
- #4 suggests that if there is a leak, it's above (in terms of altitude) the majority of the pipework/rads, as otherwise it would lose far more water/pressure than it appears to.
- #7 is a new discovery and makes me wonder whether the none-return valve is failing and letting water from the CHS back into the cold BUT even if this is the case, the tap at the other end of the filling loop is closed, so should prevent this from happening. Guess this could be caused by simple heat conduction.
My Questions:
- Are any of my assumptions wrong?
- Does anyone have any more steps I can use to troubleshoot the problem further?
- Does anyone know what my problem might be?
Apologies for the long post, but thought it worth spelling out everything I know or think I know as I'm at my wits end with this issue. Fortunately the hot water is fine.
Huge thanks in advance to anyone who can help us, we're first time home owners and this problem is stressful to the point we are tempted to sell the flat.
Cheers,
Bram
