Boiler Pressure Help With Worcester Bosch Boiler Green Star 30si Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[Ronnierome]

Hi,
Wondering if anyone can point me in the right direction.
I have a Worcester Bosch boiler green Star 30si.
It keeps losing pressure, it doesn't seem to be losing it from radiators as I have checked them all for air but all full of water and heating as they should, the pressure dial does go up to about 1 bar when heating is on but drops back down to near zero when off, I top it back to 1.5 bar but a couple of days it's right down again.
Cheers for any help.

[ericmark]

Odd thought I had posted answer, anyway I would look at the expansion vessel, normally inside the boiler there is a tank with water one side and nitrogen the other and as water expands the nitrogen compresses, if either the nitrogen leaks out or the flexible separator fails then when water expands it be be ejected and when it contracts pressure will drop, there is normally a car tyre type valve on nitrogen side, and air will normally work just as well.

The rub is to remove the cover to get at it, often means breaking the gas tight seal, so needs a gas safe guy to do it.

You can get tanks which can fit anywhere on the system, mainly for when a very large system and too much expansion and contraction for built in one to handle, never bought one, so not a clue on cheapest option.