British gas 330+

[darren bastin]

Working on a house with the above boiler and noticed when I turned it on it ignited with a bit of a bang. The customer says it often does this and has on occasion gone to F1( tried to ignite 5 times without success). Does any body have any ideas or are familiar with this boiler , I would have thought that if the boiler attempts to light the gas valve opens but no ignition the fan would have blown the gas away and so not lead to explosive ignition. Could a faulty spark electrode / igniter lead to noisy ignition or am I barking at the wrong tree. PS does any body know the wherabouts of a manual?

 

[southcoastboile]

could be a few things, check gas valve for letby, check ignition, probes etc, also check flue connections are ok, min bp set correctly, burner clean and unobstructed, same with main heat exchanger. Check spark generator, all of the above will hopefully give you an idea what to look for, im not sure what the boiler looks like off the top of my head.

 

[quality]

its a gloworm hxi and it could be a few things but if your not gsr don.t mess with it

 

[diamondgas]

Isn't it a repackaged Glow-Worm .. I'd suspect the spark electrode. Did you take it out and check to see if it looked distorted?

 

[darren bastin]

It is a re-badged glow-worm. I think you can check the gas valve using potentiometers on the pcb and using my analyser. Being forced draught zero govener there is no min bp? so can i use the hxi manual? daimond gas I will open her up and have a look when Ingo back with a manual. Any body had this on the glow worm hxi?

 

[Backboiler]

I think you have to check the fan speed on this boiler. It modulates, so you have to force it to max fan speed by turning up a potentiometer on a user board in order to gas rate it. As you can't check the BP, you have to ensure that you have 20mbar at the gas valve inlet. Oh, the electrodes need checking. If you're not GSR then find someone who is

 

[darren bastin]

Thanks , by the way lads I am gsr. So are we saying if that dodgy electrodes , or the wrong fan speed can cause explosive ignition?

 

[southcoastboile]

assume you are gsr if you have an annalyser, some of what I said earlier wont apply then, i.e min bp. most likely fault is the probes. Run it on max, check the flue gasses, that will tell you if the fan speed etc is ok as backboiler has said. Check wp on inlet valve below boiler rather than gas valve if poss. Check spark generator, I have had the same fault on an ideal boiler, worked fine 9 out of 10 times, the odd time it would bang on ignition like it was about to fall off the wall.
If you suspect probes you can always remove them, turn off gas, put demand on with the probes left hanging and see if you are getting a sprak every time

 

[diamondgas]

Thanks , by the way lads I am gsr. So are we saying if that dodgy electrodes , or the wrong fan speed can cause explosive ignition?

You have a pre-mixed explosive mixture of gas forced into an enclosed space. You want it to light immediately otherwise it doesn't take long for that mixture to build up. I've seen an Hxi flue outlet look like a turbo charged car exhaust shooting out flames...I was amazed the boiler stayed on the wall!!!

 

[darren bastin]

thanks for that diamond gas. Sorry if I labour points but I installed for many years but now I am getting asked to do more maintanence , I am usually successful but need to check my understanding with more experienced blokes so any help is always appreciated. By the way what was the problem with the Hxi?

 

[diamondgas]

thanks for that diamond gas. Sorry if I labour points but I installed for many years but now I am getting asked to do more maintanence , I am usually successful but need to check my understanding with more experienced blokes so any help is always appreciated. By the way what was the problem with the Hxi?

The Hxi in question shooting out flames had a warped electrode. The gap had grown to a pint where it either didn't ignite or did after a lot of gas had built up!!! 🙂

 

[Doodlebug]

Thanks , by the way lads I am gsr. So are we saying if that dodgy electrodes , or the wrong fan speed can cause explosive ignition?

Are you sure you are gsr, you are asking very simple questions, ie: can dodgy electrodes or the wrong fan speed cause explosive ignition. Think about it, what do you think?

You also said this "fan would have blown the gas away"
Are you serious? Please get someone who knows what they are doing.

 

[darren bastin]

Thanks for the constructive reply. The Acs exams are not centred on detailed fault finding. I applaud all those who have the patience and skill to answer questions to a bloke who after installing for many years is trying to check his understanding and improve his knowledge. This is a great friendly forum. I wish like some engineers i had been born with the all the answers , unfortunately i have to ask and question in order to advance

 

[Doodlebug]

Thanks for the constructive reply. The Acs exams are not centred on detailed fault finding. I applaud all those who have the patience and skill to answer questions to a bloke who after installing for many years is trying to check his understanding and improve his knowledge. This is a great friendly forum. I wish like some engineers i had been born with the all the answers , unfortunately i have to ask and question in order to advance

Sorry mate, just you come across so many people who play with gas appliances when they haven't got a clue it's scary some of the things you see as I'm sure your aware. I will put some pictures on here which will make your hair stand on end lol


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[darren bastin]

Please do so , sorry if my reply was a bit sarcastic. I find this forum valuable , like a lot of gsr plumbers if you are a one man band you dont often get the chance to talk about work. The only Gsr blokes I know seem to Know less than me and that is scary.