Boiler cuts out when case on.

cirks · 14 Sep 2012

An update on my original issue - //www.diynot.com/forums/plumbing/ignitor-burnt.335632/#2497651

Following unsuccessful diagnosis etc from the initial gas safe chap, I've gone to Potterton and got them to take care of it as part of a 1 yr warranty and repair deal. Based on the parts replaced and time spent so far by their chap, this financially is probably a good move.

However, the latest is that after replacing PCB, gas valve, electrodes and some cabling, he discovered that the boiler would only stay alight with the casing off. It appears that as soon as the case is put on, it cuts out as if it's attempting to suck air from the inside of the casing rather than through the flue.

So, he's now left saying the only thing it can be is an issue with the flue seals. There doesn't appear to be any visible blockages from the outside so, does this sound like the most likely scenario?

The problem now is that of course they (Potterton) don't 'touch flues' so it's now up to me to get someone else to do it or DIY? Can you guys offer advice please?

Much appreciated

stardanny · 14 Sep 2012

I know what is wrong but cannot tell you.
Get another gas safe man who know what to do.

Dan.

cirks · 14 Sep 2012

stardanny said:
I know what is wrong but cannot tell you.
Get another gas safe man who know what to do.
Dan.

So - you can't tell me whether you agree with the Potterton chap or not and another Gas Safe guy? Why not tell me and then at least I can ask someone round to deal with it and allow us to get our boiler operational. It is diyNOT and therefore I'm not going to be doing it.....

twgas · 14 Sep 2012

I'd say it may not need a new flue, but it is probably a "gas safe controlled" part so I will tell you no more.

muggles · 14 Sep 2012

I agree, almost certainly not the flue at fault here but another part within the boiler

cirks · 14 Sep 2012

Thanks guys. Would it help if I told you what had been replaced?

If so:
Ignitor
Ignitor cable
PCB
Ignition to electode leads
electrodes
sensing tube checked
combustion seal
ionisation electrode
gas valve

visual inspection of flue NTC
visual inspection of outside of flue

I can understand your sensible reluctance to state what to do or what it is but I will not be doing the work myself! What is an issue is that I've now had a boiler gas-safe engineer and a potterton engineer to try to resolve the issue unsuccessfully. I would prefer to be able to contact someone else with at least a pointer (for me) before they try to diagnose.

Thanks again

muggles · 14 Sep 2012

Yeah, none of those would be what I'd expect it to be. Common fault, any competent engineer would be able to sort this

cirks · 14 Sep 2012

muggles said:
Common fault, any competent engineer would be able to sort this

Perhaps not common enough for Potterton to know?

Unfortunately neither of you that have responded are anywhere near me so trying to find a competent engineer is a bit tricky at the moment!

rojaca · 14 Sep 2012

I'm intrigued. so the boiler is obviously vitiating with the comb box door on. the "combustion seal" (i assume this is the burner door seal) has been checked and is in tact, but you do not agree that it is the flue?
would have been a lot easier if the eng had checked the flue inlet prior to changing the gas valve, but with the internal damage to the boiler I can see why this might not have occured.

muggles · 14 Sep 2012

rojaca said:
so the boiler is obviously vitiating with the comb box door on

Oh really? I wouldn't be so sure...possible, but I think it unlikely

ChrisR · 14 Sep 2012

There's 4 things I can think of that it could be. There will be more. Potty man would normally be right, but maybe not!

cirks · 14 Sep 2012

I know you guys haven't seen/inspected it but the fact there seems to be a possible difference in opinion perhaps suggests it's not obvious? Anyway, I'd love to narrow it down to 4 things. So, fire away - flue....

Agile · 14 Sep 2012

Cirt, you have to understand that for common sense and legal reasons web sites cannot give information on gas matters which could encourage or air people to try to do gas work for which they are not qualified or equipped for.

Tony

rojaca · 14 Sep 2012

far more likely than not.

cannot see how the new g.v could possibly have been set up though if products mixing.

until someone tests the air inlet for flue gases we cannot be certain. I am unaware of any "common issues" on this blr which cause this fault, other than a faulty internal flue seal.

cirks · 14 Sep 2012

rojaca said:
I'm intrigued. so the boiler is obviously vitiating with the comb box door on. the "combustion seal" (i assume this is the burner door seal) has been checked and is in tact, but you do not agree that it is the flue?
would have been a lot easier if the eng had checked the flue inlet prior to changing the gas valve, but with the internal damage to the boiler I can see why this might not have occured.

It wasn't even igniting properly with the combustion box door off before replacing several of the bits (particuarly PCB etc) but you're probably right that there was other damage which needed to be sorted first.

You mention the flue inlet, I assume as the external visual inspection doesn't show anything, you mean potentially a blockage in elbow into box?

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Boiler cuts out when case on.

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