Glowworm - Fuelsaver 65F - Not lighting

[mgtechman]

The pilot light lights but the spark generator keeps sparking and the main burner doesnt light. Having read the manual it points toward the Sequence board so I replaced it. Still the same I then replaced the pilot jet, flame sensing device and HT lead still to no avail. Stripped the gas valve and all looked OK. Desperate I got a Corgi guy in who guessed!! He said if youve changed all that mate it must be the gas valve. So I spent £100 replacing the valve and it still wont light. If I energize the main burner solenoid on the gas valve it lights up a treat. I have now measured the voltage generated at the flame sensing device because I am convinced its the sequence board despite haveing fitted 2 new ones already. I am seeing 150mv on the end of the flame sensing electrode is this enough ?? Can anyone help ?

 

[bripl]

check polarity

 

[ArtfulBodger]

Blimey! wouldn't you have been better off buying a new boiler?

 

[mgtechman]

Check polarity of what ??

I might have been better off and still maybe, but I am hoping I can recover the cost of the new parts back from my supplier and the £58 guess from the corgi guy.

 

[ChrisR]

I reckon he means check that Live and Neutral aren't reversed, but if it WAS working...

Check the air pressure switch is changing state on both output pins. The sequence isn't always what you'd imagine.

 

[mgtechman]

Checked all the polarities and they are all as the manual. The air pressure switch seems unusual with boiler off I get continuity between P & Pin1, The fan comes on the I get continuity beetwen P ,Pin 1 & Pin 2 Then when the pilot lights . If I then Short a mains supply to the main gas solenoid, the main burner lights and the air valve has continuity between P and Pin 2 ????? Whats going on

 

[ChrisR]

The flames can help the gas through the "gas"pressure switch so once its on it stays on, perhaps.

SOunds like the aps is erratic though I wonder if you meant exactly what you wrote!
It would be diagnostic if you could simulate the aps - say with a microswitch on leads taken out of the box - which you won't have. If you canget at the aps you could blow VERY gently into the appropriate side to get it to switch at the right times and see if that made it work. 'course I'd never do such a thing, with the rubber hose off my U gauge.
If it did work you'd clean the tubes, venturi and fan, only if you were crogi regd of course.

 

[mgtechman]

Sorry chaps been away for a week. Right I have removed the fan and checked it functions OK. I have removed the Air pressure switch and checked it calibration & function on the bench with a manometer. I have blown down the pipes to make sure they are clear. The Air pressure switch only has one pole and its working fine, if it didnt detect a pressure in the case and a depression in the flue the pilot would not light. If I energize the main burner solenoid it still fires up until the thermostat cuts in and then it wont restart the main burner but will light the pilot. ??????????

 

[PEDANTICVINDICTIVEMAN]

Certainly a weird one, have you tried phoning Glowworms tech line ?

 

[mgtechman]

Well, tried to phone Tech line, and was told I would have to get a Glowworm Engineer out, Tried them and they said they couldnt come because they were too busy . Got Back onto Tech andspoke to a very helpful guy who said Check Polarity !!! Hang on I thought "BRIPL" suggested that, what do you mean I asked ? Check difference between Earth and Live or Neutral and see which wire the 240v is coming in to the boiler. Sure enough I've got 240v on my Neutral !!! Apparrently as my missus keeps reminding me loudly it hasnt worked since I replaced the programmer in the summer !!!! I found an incorrectly wired feed to the boiler in the programmer . Expensive wiring error, anybody want to buy a Sequence board and a gas valve cheap ???
Thanks for your help guys.

 

[ChrisR]

Now which bit of
"check that Live and Neutral aren't reversed,"
didn't you understand?!!!

I do buy serviceable spares - email me. Clck my name in the postings list view.