Explosive ignition problem

[Bhoydavid]

Hi all, just noticed recently that when my boiler in the house first fires up it makes a noise which I can only describe as someone a bit away dropping an old metal bin lid on the ground. I reckon it's making such a racket due to explosive ignition but it has only started over the last couple of ideas. Anyone any ideas as to why it's sudden
doing this? Cheers

 

[Bhoydavid]

Its a potterton promac combi 33 he. Just noticed there that the front cover seems to have a dent in it that you can push in and when it fires up it 'pops' out

 

[gasmanrob]

Depends on the boiler some times the electrodes have warped and have a weak spark allowing a little more gas into the chamber before it ignites.

Could be a vacuum issue the sudden pressure behind the ignited burner causes the case to suck its sides in in which case you have an air flow problem.

flue clamp seal perished re circulation of its own air giving incorrect mix upon start up

 

[gasmanrob]

If it's prom ax combi look at the electrode gap should be about the size of a pound coin give it a clean with wire wool to

 

[Bhoydavid]

Cheers lads will have a look later on

 

[mutley racers]

I've had explosive ignition on my boiler for 3yrs now. I have changed electrodes, changed spark igniter, inlet pressure great, cleaned condensate, cleand out sump and flue ways and it is still doing it. Rather annoying it is

 

[Ermintrude]

U checked low burn setting as well as high?

 

[mutley racers]

Doesn't have low burner pressure, it's just a standard Main heat only boiler

 

[Ermintrude]

Which one ? Tried it with door off?

 

[mutley racers]

Main 15HE. No not tried it with the door off

 

[Irish]

Main 15HE. No not tried it with the door off

Go on!! live a little fella it's Saturday night try it out!!

 

[Ermintrude]

Our lass loves it with the door off makes her feel 21 again. ..... 21 stone
(Edit) she's never been more than a size 12 so a tad unfair she's got one in the oven so forgivable

 

[Irish]

Our lass loves it with the door off makes her feel 21 again. ..... 21 stone

Lol classy edit feel kinda bad now

 

[TBServices]

Condensate running okay?

Electrodes is first thing that springs to mind, too much gas in the camber

 

[pipefitter]

Got this on a customers promax ,let us know if it electrodes

 

[pipefitter]

Had this a while back n some ariston clas system boilers turned out to be the PCB

 

[Bhoydavid]

The problem seems to have disappeared, anytime the boiler has fired up today it has done it without the banging noise. Strange

 

[buckley plumb]

horrid boiler - electrodes and lead can be troublesome also check the door seals and the burner these are known to come apart and can melt the boiler

 

[mutley racers]

Which one ? Tried it with door off?

Will try this tomorrow night then

 

[mutley racers]

Go on!! live a little fella it's Saturday night try it out!!

Sorry feller, I wasn't brave enough to have a go. Especially on a saturday night. The wife goes nuts when ever I start stripping things at the weekends. They usually end up going from bad to worse!

 

[Irish]

Sorry feller, I wasn't brave enough to have a go. Especially on a saturday night. The wife goes nuts when ever I start stripping things at the weekends. They usually end up going from bad to worse!

Including her or just inanimate objects?

 

[Ermintrude]

I love solo 3's and all of their potterton. / main children

No so keen on delinquent cousins "GA" family tree

 

[mutley racers]

So I tried it with the case off today. Still exploding! So phoned baxi, he got me to check gas valve. The 1st 2 pins on the left were 3.5k ohms when they should be 1.5. So he believes it is letting too much gas pass. Need a new valve apparently.

 

[mutley racers]

Hmmmmm

 

[mutley racers]

Jusy bought myself a gas valve and now I csnnot get to the nuts to take it out. It says in the book the valve comes with a service spanner but it don't. What do you guys use?