WORCESTER 28i BOILER PRESSURES GOE TO ZERO AFTER HOT WATER OR CENTRAL HEATING RUN.

[PHIL269]

I have re pressurised my Worcester Greenstar 28i junior boiler but after central heating or hot water is run it goes back to zero bar when not on.
It did this during summer when central heating was off and I only used hot water.
When heating is on it stays near zero bar and when heating is on the pressure goes up to 2 bar

The heating and central heating are working ok, but just wondered if this is normal as I thought it should be at 1.5 bar when boiler is off ?

I have never bleed the radiators would this cause the problem and I haven't serviced the boiler for a while could this help and who is best to do a service , british gas or Worcester ?
Any advise is much appreciated please.
Thanks
Phil

 

[footprints]

Not normal sounds like your pressure vessel is shot, might need pumping up but usually needs replacing it's a common fault lots of posts on here about it.
Chances are if you top up run the boiler and go outside you will see water discharge from the 15mm pressure relief pipe.
Can just be a faulty valve, but it is really one of those jobs for a gas safe engineer.

I would go with British Gas myself (just wait for the howls of disdain from other members at that suggestion!) get a contract then it will be serviced each year without fail, they will come out at short notice weekends and holidays unlike being able to phone up the makers during working hours only.
Local independent guys can be fine but if your boiler goes wrong and he is in Majorca it's no help to you!

 

[PHIL269]

Thanks for the help , much appreciated

 

[rarara]

i have the same issue with mine. any idea of the cost of both a service and replacing the pressure vessel if that is the issue?

also, if it is the pressure vessel does this need fixing quickly before the whole thing stops working or can it limp along in its current state for a while?

 

[flameport]

if it is the pressure vessel does this need fixing quickly

Yes, as continually topping up introduces fresh water which contains oxygen, this will lead to extensive internal corrosion.

 

[Mr Chibs]

Just curious, is this the expansion tank you guys are talking about?

I had similar issue on a glowworm boiler, it was under contract at the time.
When BG came out, first he tried to re-pressurise it... with a bike pump... there is a valve just like an inner tube, from memory he said 30 psi.

Had same problem a week or two later, turned out there was crud from the small braided hose connecting this expansion tank to the boiler, this was removed, cleaned, and had been working ever since.

 

[footprints]

Just curious, is this the expansion tank you guys are talking about?

I had similar issue on a glowworm boiler, it was under contract at the time.
When BG came out, first he tried to re-pressurise it... with a bike pump... there is a valve just like an inner tube, from memory he said 30 psi.

Had same problem a week or two later, turned out there was crud from the small braided hose connecting this expansion tank to the boiler, this was removed, cleaned, and had been working ever since.

Yes an expansion tank usually red in colour, round or square and a bit bigger than a washing up bowl. You had a bit of luck with yours it's usually the diaphragm inside that goes.