I have a baxi genesis 80 combi.
It will not fire up. No gas flow.
If I take off the outer combustion box cover, gas will flow and it will spring into life and ignite. As soon as I replace the outer combustion box door, it dies.
What could be wrong?
The fan runs.
Steve..
Blocked flue. Blocked tubes to Air Pressure Switch.
Blocked inlet flue?
Hole between inlet and outlet in flue.
Faulty/bunged up pressure switch/venturi for fan.
disconnected/holed pipe to same.
Etc.
Yes, there is a spark and it will fire up if the outer combustion box cover is off. If it is on, it will not even spark.
Steve...
Stripped it down and blew through pipes etc.
There was no obvious blockages or large amounts of debris, but after reassembling, it fired up and worked as it should.
Thanks for the advice.
Steve...
Hmmm, after working perfectly yesterday and most of today after my fiddling with it, the fault has returned again.
I am therefore guessing that it is the air pressure switch that is faulty and my fiddling must have persuaded it to work correctly for a while.
Unless someone says I should not, I shall order a new air pressure switch in the morning.
Steve..
Have you tried shorting it out of the circuit to see if the boiler fires without it?
IANAP
Rob
No, how would I do that?
I have tested for contuinity across 2 of the three terminals as suggested by the handbook troubleshooter and it passed the test.
Steve..
The air-pressure switch was faulty on my boiler but it took a long time to diagnose as the problem was intermittent. Anyway, the plumber connected a wire across two of the terminals which bypassed the switch entirely and the boiler worked. This narrowed it down to a flue or air-pressure switch problem. Couldn't see anything wrong with the flue so the air-pressure switch was changed and the boiler's been fine ever since.
Obviously this should only be done to diagnose the problem and not as a permanent fix!
Cheers
Rob
But which terminals to bridge?
There are 3 terminals.
P1, P2 and one other.
Steve...
Sorry, can't help. There was a circuit diagram on the inside of our boiler casing but I'm guessing there isn't on yours.
Cheers
Rob
I do recall a circuit diagram on the inside of the casing. I will see if it gives any clues.
I seem to have the same intermittent problem you had, as I have now replaced the outer combustion cover and it is working fine.
The replacement switch is only about =A326 so I would not watse too much if I was wrong.
Steve..
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.