sealed hot water system pressure

john_mcl

Hello,
I am new to this forum, so bear with me...
Recently we bought a 30 yr old house and had people completely replace the gun barrel/radiators/cylinder/tanks/oil burner. (raised wooden floors)
The pressure gauge for the radiators etc was fine for 3 or 4 months holding steady at 1 bar.
Went on holidays for 5 nights over xmas, left the timer so the heating came on for half an hour each evening while we were away.
Got back and the pressure gauge reads about 1/3 bar.
Is this normal?
I put in more water using the valve, and it *seems* to hold.
I need to check the pressure bladder thing tonight in the attic, but just wanted a first bit of advice...
Appreciate it.

Lex Luthor

john_mcl wrote:

I put in more water using the valve, and it *seems* to hold.

is it back to 1bar now?

Corkey123

Just to clarify a few things you say the pressure gauge is in the attic. If this is a presurise system, as it appears to be from your description, the pressure is normally supplied by the mains, therefore your value/gauge is being supplied by the rising main (this is the source that fills the water tank in the attic) and should provide be ample presurre for your system.

If you suddenly lost pressure it can only be by a release of water fom the system. This can only be done by bleeding air out of the rads or dare I say it a leak.

Did you bleed the rads recently and forget to re-pressurise the system afterwards?

If the pressure is as low as you say your heating should not be functioning very well if at all.

Check the gauge tonight and if the pressure is stable and the heating is working just monitor it for a few days. Only worry if you experience a loss of pressure again.

JamesM

The system will work fine at 1/3 bar. It is quite normal to have to top up the system every few months - especially after the big job you did. Filling the system from scratch always brings in a lot of fresh water with plenty of oxygen.
Maybe you read the pressure while the system was off. The pressure will always be a bit lower when the system is cold, than when hot.
Don't touch the expansion vessel :eek:
As Martin says, just monitor it
Jim.

john_mcl

Thanks for the info.
Pressure was 1/3 while system was off.
I put in more water from the rising main (there is a lever/handle next to the pressure gauge) and now its about 1 bar while off. It goes to about 1 and half bar when system is on. The radiators heat up fine.
That's one thing I have never done, bleeding the radiators.
That might be the answer - would that explain why it only dropped in the cold weather or when there is less usage?
The pressure unit in the attic didnt seem to have any leaks anyway and I am really hoping to eliminate the leak possibility as we also put down new semi solid flooring over the raised wooden floor.
Thanks
John

Corkey123

John

Just sit back and monitor the system.

If the rads needed to be bled you would know by the inconsistent heat from the top to the bottom of the rad. If this is not the case leave well enough a lone.

Just keep an eye to the pressure and make sure it doesn't begin to drop below 1 psi

Cheers