Ravenheat presure problems

[PeterWG]

I have a Ravenheat CSI 85 A boiler and have had problems with the pressure dropping over a couple of days. To be honest this has gone on for years now and I just keep topping up pressure from the filling loop. In my looking up this issue on various sites I came across a fairly old thread which is the same as mine. I have had Home Care out a few times recently but the problem persists. I increased the pressure to 2 bar turned off the boiler and went under the floor to locate the isolator valves,I couldnt find them so came back up to find the pressure had droped down by 0.4 of a bar. Whilst under the floor I checked the pipe work for leaks, couldnt see any, as another test I had put a bag over pressure release pipe and in the morning when the pressure had dropped to about 1.3 bar I checked the bag and low and behold it was full, a small freezer bag. Ithought that the PRV was set to 3 bar???. I have now found the isolator valves and now intend to to do the test but I am confused with the valve going at 2 bar

 

[terryplumb]

If the PRV doesn't close fully it will pass water at virtually any pressure.

 

[MeldrewsMate]

The PRV should be replaced but, just as importantly, the cause of the PRV passing has to be cured to prevent recurrance.

A proper sealed system should never require regular topping-up. In your case it has gone on for so long that any protective chemicals (inhibitors) added will have been seriously diluted by now - add inhibitor after curing the leak (the PRV).

1. Check the Expansion vessel pre-charge pressure, that is it's air charge with 0 bar water pressure.
2. Replace the Expansion vessel if it proves to be faulty.
3. Replace the PRV
4. Top-up with inhibitor.
5. Fill the system.
6. Drink tea, relax knowing the job has been done and no more topping up is needed.