Help diagnosing problem with Valliant Ecomax VU186EH boiler

[IDN101]

Boiler stopped working last Thursday

Pressure was virtually non-existant (got a leak in the system somewhere, because it does reuire filling on a "quite regular" basis). So I top it to 2 bar via the filling loop.

I tried resetting it at the fused spur.
When switched off and on at mains, it would fire up and then almost immediately I would see the pressure guage start to oscillate quickly, just as loud knocking / banging sounds came from the boiler- then it would close down very soon after. "F.22" would then be displayed on LCD panel/

British Gas came out Monday evening. He said the pump was jammed. Freed it with a screwdriver. Boiler now started and stayed on for 5 minutes- then banged / closed down. He freed it again and sprayed with WD40. He said he would order a new pump and hoped this would keep it going until part could be fitted.

Boiler stayed on for approx 3 or 4 hours after he wen, then went off with a thud / bang again. I switched it off at fused spur as the replacement pump was scheduled for today.

Engineer turned up today and fitted new pump. Engineer signed the job off as resolved. Boiler ran fine for an hour or two after he went then closed down and displayed "F.22" on panel again.

I immediately phoned BG back tonight and informed them that they have NOT resolved the problem. I've now got an engineer booked for tomorrow evening to see if they can determine the problem. I suspect it wasnt the pump???

Any thoughts or suggestions as to what may be the underlying cause would be most appreciated. At least I'd be better informed when talking to the engineer tomorrow night.

Many thanks
Regards,
Ian

 

[ecowarm]

does it loose pressure straight away, ie refill, fire boiler, pressure goes over 3bar and then drops to .5 or less, then f22?

 

[IDN101]

I don't think pressure really drops that much when it tries starting. It's just sitting there at about 1.7, now its switched off.

It's just the pressure gauge jumps up and down by about .25 of a bar, each side of it's stable pressure- just as its making this terrible knocking / banging sound.

And strange it would run fine a few hours and THEN shut itself down???

Thanks once again for the reply.

Ian

 

[Gascat]

if boiler is bangin knocking you have a circulation problem ,changing the pump is all very well but did he bleed the system and make sure he vented all the air from the boiler. sounds like expansion vessel may be knackered (red tank at back of boiler) find the valve (same as a car tyre) and push the pin in a touch see if water comes out if it does it needs replacing.also is there water coming from pressure relief valve outside (could be why your losing pressure). could be sludged /scaled up in the boiler and you have a blockage hence pressure gauge jumping about.? good luck

 

[tamz]

F22 is kicked in if temp differential is high. Assuming pump is now ok i would be checking your system or hex. Sometimes things are not all they seem.

 

[Gascat]

could even be faulty stats on flow /return but i doubt it

 

[mattyp]

Possibly a blocked plate heat exchanger , also make sure all the trvs on the radiators are not shutting down ( if you have them ) needs to be at least one radiator on all the time that the heating is on.

 

[IDN101]

Many, many thanks guys for all you help and suggestions.

British gas Engineer due at 16:00 today- so I'll see where we get to then.

But I do get the feeling that they are just clutching at straws now and that no one is taking a systematic, methodical approach to diagnosing the problem. At loeast I seem to now have a good contact at BG in the call centre who is monitoring this case personally- because everytime I have had to phone them back, I get through to someone different and have to trawl through all the history, etc, etc.

I'll keep you guys posted on progress / the outcome, if the info is of any use to you? (with regards similar problems you may come across in the future)

Cheers once again,
Ian

 

[washer]

Give the original engineer a break, he replaced a stuck pump, and it was running and working fine when he left, hardly clutching at straws.

The ecomax in my experience is the one of the worst boilers Vailliant have produced, there are 2 black flexible tubes inside the boiler (one on the flow and one on the return) that are prone to blocking up, I suspect these need changing, and are causing it to overheat.

Also I have changed alot of water pressure sensors on these boilers, Vailliant have modified the original.

 

[IDN101]

Yes, you're right- came across as a bit harsh. To be fair, each individual at BG has been really good. I'm just venting my frustration at not having the thing running for a week now.

Cheers,
Ian

 

[tamz]

So is it fixed now?