Please Help

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Gasguru said:
Do this exactly:

Open the PRV to drain boiler down to ZERO bar.

Put a pressure gauge on the expansion vessel schraider valve (looks like a car tyre valve).

The pressure should be about 0.7 Bar. If its lower than this pump up the vessel.

Make sure the boiler pressure gauge is showing zero when you check the expansion vessel pressure.

Replace the automatic air vent.

Clean out or replace the PRV.

Re-fill the boiler to 1 Bar maximum.

Bleed radiators and reset boiler pressure to 1 Bar.

Now tell us what the pressure does when the rads get hot.

have you done this exactly yet?

air coming out of the expansion vessel sounds like good news to me but you have to do the above exactly. when you pump the vessel up you have to have the prv open ( or a drain cock).....water may come out when you do.
 
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Hi
We have done this and the aav is ok not leaking but we put the air in the exp vessel aand it just comes straight out of the pipe out the back and the pressure will not rise?
Any suggestions please, we think it is the valve or the seat in the prv that has gone would this then need replacing and is it the prv that needs replacing - is the seat problem in there ?
 
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If you can't get the pressure to rise in the expansion vessel the diaphragm in the vessel is holed.

Either replace the unit in the boiler or plumb in a new vessel.
 
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Gasguru said:
If you can't get the pressure to rise in the expansion vessel the diaphragm in the vessel is holed.

Either replace the unit in the boiler or plumb in a new vessel.

That was suggested about 15 posts back.
 
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If you read you will see I am not asking about the ex vessel , i believe that is ok, as per threads back, I am asking about the seat in the prv. If it is in there or the pipe and can I replace it ,as I think the prv or whatever, is not closing down as per gunk as explained earlier and I need to replace where the seat is. I just need to know if it is the prv that it is in or further on.Thanks
 

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