Bit of a long lost this one... so hope you don’t get bored 
We've had the pressure dropping in our sealed system for the last couple of months. It's ranged from between 0.5 and 2 bars depending on how much we use the heating. The more the heating is on, the better it seems.
The old knackered combi boiler has been replaced with a nice new Worcester, so I'm confident it's not boiler related. The pressure was dropping before this, and started at the time we had problems with the old boiler and had the system drained down...
We have isolation valves on the downstairs circuit. Turning these off results in no pressure drop, therefore the leak must be on the downstairs circuit.
After a thorough inspection of the system I noticed the drain cock under the back door step dripping. This made sense seeing as it was disturbed around the time of the boiler problems. Fixed that and monitored the pressure over the next day and it was still dropping, but maybe slightly less.
So, I pumped pressure up to 2 bar in a cold system. And checked for leaks on rads, valves, bleed valves, etc. I noticed a union nut leaking a drop every minute. Tightened it up a little, which stopped the leak. Monitored the pressure over the next day and it was still dropping, but maybe slightly less.
Next, turned off all rad valves. Three sprung spindle leaks. Tightened up two, and packed one, all fixed. Monitored the pressure over the next day and it was still dropping, but again slightly less.
The downstairs pipe work is in the screed, so I guess the leak could be there. There are no damp patches appearing. Downstairs is covered by laminate or tiles.
A lot of the valve spindles are green. Does that indicate seepage? Could it be possible they are leaking only at a certain CH temperature and/or pressure?
I think my last options are:
- To get a leak detection specialist in with use gas, ultrasonic, thermal imagining equipment, etc
- Try Sentinel or Fernox leak sealers (which I'm not overly keen on).
- Maybe pack all the green looking valves in case they are weeping.
Any suggestions on any of the above would be greatly appreciated.
We've had the pressure dropping in our sealed system for the last couple of months. It's ranged from between 0.5 and 2 bars depending on how much we use the heating. The more the heating is on, the better it seems.
The old knackered combi boiler has been replaced with a nice new Worcester, so I'm confident it's not boiler related. The pressure was dropping before this, and started at the time we had problems with the old boiler and had the system drained down...
We have isolation valves on the downstairs circuit. Turning these off results in no pressure drop, therefore the leak must be on the downstairs circuit.
After a thorough inspection of the system I noticed the drain cock under the back door step dripping. This made sense seeing as it was disturbed around the time of the boiler problems. Fixed that and monitored the pressure over the next day and it was still dropping, but maybe slightly less.
So, I pumped pressure up to 2 bar in a cold system. And checked for leaks on rads, valves, bleed valves, etc. I noticed a union nut leaking a drop every minute. Tightened it up a little, which stopped the leak. Monitored the pressure over the next day and it was still dropping, but maybe slightly less.
Next, turned off all rad valves. Three sprung spindle leaks. Tightened up two, and packed one, all fixed. Monitored the pressure over the next day and it was still dropping, but again slightly less.
The downstairs pipe work is in the screed, so I guess the leak could be there. There are no damp patches appearing. Downstairs is covered by laminate or tiles.
A lot of the valve spindles are green. Does that indicate seepage? Could it be possible they are leaking only at a certain CH temperature and/or pressure?
I think my last options are:
- To get a leak detection specialist in with use gas, ultrasonic, thermal imagining equipment, etc
- Try Sentinel or Fernox leak sealers (which I'm not overly keen on).
- Maybe pack all the green looking valves in case they are weeping.
Any suggestions on any of the above would be greatly appreciated.
