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bewsh

Plumbers Arms member
Plumber
Gas Engineer
Jan 15, 2013
608
106
43
Pontypridd, Wales
Alright guys?

The above boiler is going to fault light 15 seconds after putting a demand on. Doesn't spark or anything, red light comes on solid and the yellow light flashes twice, MI's suggest a fault with the gas valve or PCB. Checked resistance of the gas valve coils, they are spot on. Checked continuity down gas valve lead, which was fine. So MI's say faulty PCB.

Replaced PCB but the exact same fault is there. Baxi tech just advised to order new gas valve and lead, but I would have thought that it would still spark, even if the gas valve was knackered?

I also checked the thermostat and potentiometer resistances, which were all spot on also.

Anyone had this issue before? Or offer any advice? Cheers!
 
Not that problem but had a few with that kind of boiler,

Did u check resistances at all the different pins for the gas valve ,
PILOT VALVE PINS 4 n 5 = 2.8kohms
MAIN VALVE PINS 1 n 2 = 1.6kohms
PIN 3 To 1,2,4 n 5 should be more than 2Mohms
Continuity of leads aswell
 
Yep, all resistances were spot on. I even tried putting a match to the pilot assembly when setting a demand to see if there was any gas coming through at all, but nothing. No spark, no gas. Standing pressure was fine as well. Electrical checks all ok as well.

I also changed the spark lead just in case there was an issue with that, but still the same.
 
Take gas valve out and check it...could be full of crap... Also check pilot injector to see if it's blocked.
 
Take gas valve out and check it...could be full of crap... Also check pilot injector to see if it's blocked.

It's not sparking though, faulty pcb I reckon. Ring Baxi again and speak to another engineer.
 
pcb will be faulty,had a few do this,cant see it being gas valve it should still spark,just check for RP and continuity of ign lead and probe
 
Last edited by a moderator:
Ye, I didn't bother with the new gas valve as all checks were fine on the lead and valve. Got another new PCB, and it worked fine!

Always a bit of a head scratcher when you get a new PCB and it has the exact same fault on it!

Cheers for the help anyway guys!
 
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Ye, I didn't bother with the new gas valve as all checks were fine on the lead and valve. Got another new PCB, and it worked fine!

Always a bit of a head scratcher when you get a new PCB and it has the exact same fault on it!

Cheers for the help anyway guys!

It's a proper pig when you get that. Worst thing is you start to doubt yourself.
 
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