Help, central heating packed in.

[ss]

Its my neighbours so trying to help. Vokera compact 25A,sealed system I think.

Still gets hot water if turned to hot water only and rads off. Fault is A01 ignition failure,flame not sensed, internal fault.

When the heating is turned on it makes lot of gurgling noises from the boiler (pump) which sounds like trying to pump but water not circulating then boiler cuts out.

I would suspect a frozen pipe although the heating was working until 2 pm today and then turned on around 7pm when it failed.Condensate pipe goes to the waste stack (internal) so not that.

Any thought/ideas short of trying to get an engineer out which is likely impossible with this cold weather and emergencies.

[Andy Burns]

Seems odd that it will light for water, but not light for heating.

What happens if you start it by drawing some water, then turn heating on while it's already lit?

[ss]

Let me think......I turned it to hot water only and then heating + hot water with water running, Then I am sure the fault code appeared, cant be sure but I think the hot water continued. I could double check on that tomorrow.

[John Rumm]

Do you actually hear it light the burner?

(and hear it spin up the fan, spark etc)?

[ss]

The problem I have is with it being a neighbour I dont want to start stripping it down, mine would be in bits by now :-)

The boiler calls for firing and the temp gauge rises by a few degrees and then appears to cut out, the pump still appears to continue running as it then starts making lots of gurgling noises, I am hazarding a guess that the pump is pumping but as water is not flowing due to a blockage (frozen) a safety circuit is cutting the gas off and creating an ignition failure.

[Malcolm Race]

3 port valve sticking? try exercising manually

Malcolm

[Dave Liquorice]

What is the system pressure? When was the pump last bled? Do (did...) all the radiators get properly hot, right to the top?

I'd expect the boiler to cut out with no or limited circulation. But not with "A01 ignition failure,flame not sensed, internal fault." I'd expect boiler overheat or no flow. And as the thing works for HW why does the ignition/flame sense work for that but not CH?

[ss]

System pressure about 1.25, I doubt if pump has been bled. Rads I will check with neighbour tomorrow and bleed the rads just in case.

[Brian Gaff]

Yes but unless the pipes go outside its very hard to freeze heating pipes! Brian

[charles]

That assume the boiler is running.

[ss]

Looks like they have a gas plumber this morning so I will back off now. Googling stated `gurgling` noises is a symptom of frozen condensate pipe so I was intending to disconnect the condensate pipe temporarily to see if that cured it. No doubt I will find out later what the cause was. Thanks all for the suggestions.

[Davidm]

Or if it (the boiler) has an internal syphon trap on the condensate outlet that has become blocked with gunge. Had that on my Worcester Bosch boiler, made lots of hissing/splitting/gurgling noises before cutting out - on the coldest day of last year, of course!!!

I didn't know about that syphon, so had to call a man in (and wait). Having watched him I can now do it myself, simple.

[newshound]

I was going to say condensate system too, especially this weather

[ss]

That was my original thought but it looked like it was fed into the internal stack so initially dismissed it.

[ss]

Neighbour quote: the problem was from the engineer the boiler hasnt been serviced and there was a blockage. Reading between the lines it was condensate filter gunge and probably ripped them off for a service. Happy days.