Worcester Bosch Greenstar 28i Junior Problems

[davestones]

Hello -

I am having a few problems with my boiler and wondered if anyone could help me with a diagnosis. Since we returned from a short Christmas break, the boiler has not been able to continue supplying central heating reliably, and it is refusing to supply hot water unless the central heating is already turned on with the green ignition light on.

I have checked the following:

- Condenser pipe (mostly indoor, has had two kettles of boiling water poured through it but it is not blocked at all)

- Reset and recommissioned the thermostat (Danfoss RX1 and RF wireless dial thermostat)

- Every radiator bled and no air remaining in them (with the exception of the bathroom radiator, but this is isolated at its valves until a replacement gets fitted)

- Checked for any error codes on the boiler (None, though the blue light doesn't illuminate while the boiler is on and I am led to believe it should)

The heating will tend to turn on OK after the boiler is reset, and at this point the hot water will work fine but after approx 15-20 min the pressure dial will shoot up from 1-1.5bar where it tends to stay up to about 2bar, at which point the boiler cuts out completely. A "ticking" noise can be heard from the relays in thee boiler, and an ominious rumbling/gurgling noise comes from what sounds like the expansion vessel. There is no water coming from the pressure release pipe outside the house.

I am making a wild stab in the dark that there is a large amount of air and/or contamination inside the boiler/system somewhere that needs clearing out. I have a British Gas engineer coming on the 17th Jan to have a look (we have Homecare) but was wondering if anything else can be done in the meantime as it's very inconvenient having no central heating!

Oh, the boiler was installed in August 2008 and has been serviced annually since then.

Ta

 

[HARALIAN]

would tell you to vent hex but may get you into trouble for taking off the cover

 

[davestones]

I'm fairly competent, assuming I am given step by step instructions. If I take the cover off and it looks too scary then I can always put it back on, it's only 4 screws after all, and not anodized/tamperproof at that..

 

[HARALIAN]

top of fan you will see an approx. 5 inch dodgy looking piece of rubber hose normally clear....... butterfly nut behind this.... open nut and run away!!!! return some seconds later and turn nut back

 

[nickso]

then watch as it leaks after you close it.

 

[bengasman]

Much better way of venting the hex, even though I doubt that is the problem.

Drain water until pressure is 0.2.
Turn heating demand on and open filling loop at the same time; close when pressure is 1.5-2 bar.

 

[HARALIAN]

we are waiting??..............!!

 

[nickso]

are we?

 

[davestones]

Patience! I am at work at the moment, will try it when I get home. If the problem is not with the heat exchanger, are there any other suggestions I could investigate, is this a common fault with this model boiler?

 

[bengasman]

...If the problem is not with the heat exchanger, are there any other suggestions I could investigate, is this a common fault with this model boiler?

Leaking aav due to poor installation and/or poor maintenance, common as muck on these. (Junior) i-series are very pop with cowboys.

 

[davestones]

All -

Just to feed back on this (finally, new year is very busy for my line of work) -

After the bubbling and gurgling got worse, and the boiler decided to blow its pressure valve and **** water all over everywhere, I have finally bled the heat exchanger, a rather worrying amount of air came out of it, and I have checked the pressure on the expansion vessel - this returned as 6psi so that has been reinflated to the correct level after draining the system right down. I did check the auto-air valve too, this was all clean and tidy and didn't seem to be leaking anywhere.

Fingers crossed, it seems to be working OK at the moment, obviously I am keeping a very close eye on it. I won't cancel BG just yet, mind..

 

[boilerdoktor]

was your system flushed prior to installation? sounds like a blockage caused by sludge! would get BG to check your system ph level etc but get someone else in to flush if necessary as they are very expensive and will charge you extra even though you are on homecare!

 

[davestones]

This is a long late post but finally the system has been repaired. BG first sent a contractor, who diagnosed water in the expansion vessel and repressurised it, which seemed to fix the problem. In a day or so the same problem reoccured, so they sent another engineer out today. He has replaced the pump, and got the blue light back on, and all is well

Thank you for everyone's advice.