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lambpie

Hi I have a problem with a WB Greenstar 40Cdi combi.

Any help gratefully receivd as I cant leave the boiler not working (athough it can be topped up twice a day) as there are young kids in the house and it is -5 outside.

All is well other than losing pressure (0.5 bar in 4-5 hours)

I have turned boiler off and the inlet/oulet pipes. Still loses pressure so I know it is the boilet not the system. No signs of any leaks on the boiler. No errors.

The PRV was released to reduce pressure in boiler to reduce the pressure in the system to fix a leaky rad valve a few days ago. Suspect it has not shut properly.

Taken PRV off cleaned crud off it and put it back on. Problem is slightly better but not much.

I have put a sandwich bag on the PRV outlet and fastened with string. Got 1 teaspoon in about 4 hours and lost 0.5 bar.

Tomorrow I going to replace PRV with new.

I was also going to repressureise the expansion vessel. No water came out when i pressed valve only air. Plan is to:
Close inlet and outlet CH.
Turn off boiler
Drain boiler though old PRV calve
Replace PRV valve with new
Pressureise Expansion vessel to recomended pressure i.e 0.9 bar using bike pump
repressureise boiler and open inlet/outlet valves.

Questions:
Is one teaspoon enough to drop system 1/2 bar?
Does PRV only let water out or can it let air in hence only 1 teaspoon.
Is it a good idea to also do th expansion vessel repressureise?
Are my instructions to repressureise the expansion vessel correct.
Any other idea's.

Any advice would be really appreciated.

Thanks in advance
 
Last edited by a moderator:
You require a gsr engineer to look at your boiler, you are working illegally by removing the boiler casing and so that is the only advice you will receive from these forums.

Thank you.
 
Thankyou for your help and kind advice much appreciated. I'm not GSR but the chap doing it is (He was here 3 hours today looking at it). I just want it fixed and wanted advice so I can get him out again to sort it without replacing half the boiler and costing a fortune,
 
I'd be looking for a different engineer. If he was looking at it for three hours today and didn't fix it then, well enough said.
 
Agree with sg 3 hrs and not even slotted in a robo expn vssl and swapped a prv, shouldnt be working!!
 
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