Boiler: pressure goes up, pressure goes down

FrankGrimes

I had so much hassle with the plumber I had re-plumbing my house (posted here on it before) that relations have now come to an end due to (rather ironically) him giving me an unbelievable torrent of abuse when I rang him about a leak (was planning on asking how I could fix it myself but the abuse came before I had a chance). He has since admitted to the mutual contact who organised the deal that this was as one sided as I’m making out and it was cos he was ‘under pressure’, but I’ve said he’s never stepping foot on my property again, and the fact he hasn’t contacted my mate about money explains some of his guilt.

Anyways, the other lad I had in doing a bit of the plumbing while first guy was on holidays kinda took the hump I didn’t go with him when things started going wrong with the first guy, so I’d rather not call him. All this meant that I had to learn some plumbing and I’ve now plumbed in all the appliances and the sink in my kitchen, which was tricky (8 joints due to elbows and service valves) but I have it all done now and I’m delighted.

I’ve also been working on finding and fixing the various leaks in both plumbers’ work and I think I finally have the heating system stable (it was losing pressure fast). Now when the boiler is on the pressure sits at 1 bar and when it is off it drops to about 0.8 bar – is this normal? Is it the case that a small drop like this is normal due to the pump not being on, but if it drops anymore if the boiler is off for a long time then I have a leak?

Thanks again.

JamesM

FrankGrimes wrote:

Now when the boiler is on the pressure sits at 1 bar and when it is off it drops to about 0.8 bar – is this normal? Is it the case that a small drop like this is normal due to the pump not being on, but if it drops anymore if the boiler is off for a long time then I have a leak?

Thanks again.

That is normal. Hot water expands and cold water contracts - explaining the drop in pressure.
I assume that you are closing an intake valve after you have brought up the pressure. If the pressure stays constant (either when hot or cold), for a good period of time ( a month or more) with the valve closed, then you do not have leaks. It might not need to be topped up for up to a year. Initially when the fresh water has a lot of oxygen, you may have to bleed and top up after a month. After that you could get 6 months or a lot more.
Jim.

Lex Luthor

FrankGrimes wrote:

Now when the boiler is on the pressure sits at 1 bar and when it is off it drops to about 0.8 bar – is this normal? Is it the case that a small drop like this is normal due to the pump not being on, but if it drops anymore if the boiler is off for a long time then I have a leak?

Thanks again.

Frank, mine operates identical to yours with same pressure readings you have on & off for the last 9 yrs with no trouble.

Touch wood....;)