Vaillant Combi Compact heating won't shut off!

[Agile]

Agile.
why butt in on a thread you cannot contribute anything useful to due to your lack of knowledge in regard to the operation of this appliance.

I'm sorry, I didn't realise that you had fixed the boiler for him!

 

[nickthesafe]

Mmmm OK. Having worked with circuit boards and control systems of other sorts for over two decades i wasn't exactly 'messing' around but thanks anyway. The controller was worthy of close inspection from the begginning given the strange symptoms - it was just bizarre that the CH was locking on and getting far too hot, then opening controller just to check relays before fixing the sticky cam - then won't light, i cannot believe a control unit is that sensitive that just the mere act of looking at it can be such a big deal? (well, maybe in the quantum world) But without the full system and pcb schematics it's harder to understand what does what, when and where!.

Like i said - Thanks folks and I will let you know the outcome

 

[spacethegas]

all i was getting at was that all relevant info would be helpful.

the next step was sparking or not.

check operator head voltage.

flame supervision board or ignition transformer.

dependent upon results obtained.

theres a couple of other options but we didn't get that far.

 

[nickthesafe]

HI Spacey, operator head v -ok, no power to ignition unit. Looks like Flame Superviser board, the BG man is bringing all the boards and an air switch (though i think he ain't gonna need that) tomorrow morning after todays inspection. It was pretty neato though watching him follow EXACTLY the same line of enquiry as we have been going through - I didn't have the heart to tell him, 'done that'....'and that'.....'yeah thought it might be that'....I know what it's like to have a punter do that to you - so i didn't!.

 

[Agile]

So he did not actually come to any conclusion as to the actual fault then!

Its easy for BG because they dont have to pay for the parts and can just change them by substitution until it works. Us independents have to find the actual fault because we cannot afford to buy a full set of parts first.

I once fixed one of your type of boiler after BG had failed after four days of trying. Hopefully your guy will be rather quicker.

Tony

 

[spacethegas]

if hes going to change all the boards your definitely getting your moneys worth.
see if he will leave the old parts with you. its worth a try.

 

[nickthesafe]

Yep I'll try....

 

[nickthesafe]

BG Been here all morning, changed all PCB's except fan controller - which seems ok anyway. Everything seems to be doing what it should but no power is leaving the controller to fire her up. I've got vaillant coming out next to see if they can figure it - should bl@@dy well hope so!.

 

[nickthesafe]

Just to add, after fitting all the new bits, they then took them all back again after deciding it was beyond them!. This fault really makes no sense at all.

 

[spacethegas]

i've no doubt your not smiling though.

i'm guessing bg are footing the bill. this fixed price repair must be costing them a fortune.

please keep us informed.

 

[spacethegas]

another thing comes to mind.

don't accept a new part that does not come from a sealed box.

 

[Agile]

I once fixed one of your type of boiler after BG had failed after four days of trying. Hopefully your guy will be rather quicker.

Tony

BG Been here all morning, changed all PCB's except fan controller - which seems ok anyway. Everything seems to be doing what it should but no power is leaving the controller to fire her up. I've got vaillant coming out next to see if they can figure it - should bl@@dy well hope so!.

Deja vu ?

 

[nickthesafe]

Vaillant trained guy fixed it in 10 mins, then another 10 figuring out why the boiler was lighting with the cover off, then why the fan wasn't coming on until he blew into the boiler pressure air tube. BG had refixed the air switch with both the air tubes round the wrong way AND the wires to the N.O. connector rather than N.C.

...............And the fault was the FAN BOARD! - the one board BG didn't bring along yesterday.

Might be worth remembering this - he knew from a brief phone call and description of symptons that it would be this board, he said - if everything is working but no power going out to the gas valve and ignitor, then the fan board is not telling the motherboard that the fan is working.

Thanks to everyone for your help on this. Hot shower for me tonight!

 

[nickthesafe]

i've no doubt your not smiling though.

i'm guessing bg are footing the bill. this fixed price repair must be costing them a fortune.

please keep us informed.

You're quite right, 1 man hour Monday, 6 man hours Tuesday - no fix no fee The final repair bill came to less than a hundred quid - now that I AM smiling about.

 

[spacethegas]

thanks for the update.

you learn something new every day.