Charging the air in a pressure vessel.

[Mister Dobbo]

I have a Worcester heat slave 15/19 boiler, and when I switch the boiler on the pressure goes up from 1 bar or just under to nearly 3 bar. I assume this is down to the pressure vessel diaphragm needing charging. I was wondering how this should be done i.e. with the system full of water or drained slightly.

Also when I have the heating on and I run some hot water it makes a loud growling noise! I think this could be down to the pressure problems.

Any advice would be greatly appreciated.

 

[ChrisR]

Full, if verbose instructions are in the FAQ section.

Growling could just be scale build up in the heat exchanger - age.

 

[Agile]

Before you touch anything else let ALL the air out and see if any water comes out.

Ignore the bit abiout taking 10 litres out when draining.

I did not write them!

Tony

 

[Mister Dobbo]

Thanks for the answers, I'll have a fettle with it and see if I can sort the pressure.

 

[chrishutt]

I'll have a fettle with it

Something you do with sheep in Cumbria?

 

[Mister Dobbo]

Latest: I've let all the air out and no water came out which was a relief. I then let some water out the system and opened the bleed valve on the top radiator, I then closed the drain valve and pumped the vessel pressure up to 1 bar with the rad bleed valve open. I then closed the rad bleed valve and refilled the system to 1 bar.

Would this be the correct procedure?

Sorry ChrisR/Agile I cant find the bit in FAQ which you refer to :-S Edit: I found the FAQ section!!

 

[Agile]

Latest: I've let all the air out and no water came out which was a relief. I then let some water out the system and opened the bleed valve on the top radiator, I then closed the drain valve and pumped the vessel pressure up to 1 bar with the rad bleed valve open. I then closed the rad bleed valve and refilled the system to 1 bar.

Would this be the correct procedure?

Sorry ChrisR/Agile I cant find the bit in FAQ which you refer to :-S

You should NOT have closed the drain valve until you had finished pumping the air to 0.9 Bar.

However, as the bleed screw was out that should not have done any harm.

You should have repressurised the water to 1.5 Bar !!!

Its very lucky for you that its only the air which had leaked and now after repressurising it should have taken care of this fault.

Tony

 

[wkt20]

Latest: I've let all the air out and no water came out which was a relief.

Did you let all the air out of the expansion vessel with the central heating still pressurised?

 

[Mister Dobbo]

You should NOT have closed the drain valve until you had finished pumping the air to 0.9 Bar.

However, as the bleed screw was out that should not have done any harm.

You should have repressurised the water to 1.5 Bar !!!

Its very lucky for you that its only the air which had leaked and now after repressurising it should have taken care of this fault.

Tony

The bleed valve was open so the system was open to atmosphere with low water after I'd drained some off so it wouldnt come out of the bleed valve when the expansion bladder filled with air. I've re-pressured the water system to 1 bar now. Is that OK??

Latest: I've let all the air out and no water came out which was a relief.

Did you let all the air out of the expansion vessel with the central heating still pressurised?

Yes, a fair bit of air came out but no water!