C
chris329a
Hi guys, I was wondering if anyone had any ideas about a fault that my boiler has just developed.
After a powercut, the boiler would cause the MCB in the consumer unit to trip after a few seconds. It is fine up to the point where the timer box would click and when the fan usually comes on. Due to this I unplugged the fan. The water pump upstairs comes on and it didn't trip. I even blew into the pressure switch and it would start to function as normal i.e. sparking and lighting boiler indicating the PCB was probably OK.
I bought a reconditioned fan and it did the same. After getting a British Gas engineer round, they said it was probably the PCB after doing similar tests to me.
I bought a reconditioned PCB and it does EXACTLY the same...... :disappointed:
The electrician was called in to check the circuit and it is all working fine until he checked the circuit the boiler is on. He said there was a neutral/earth fault reading and hence the tripping on the consumer unit. When I disconnected the fan it was OK, once again showing the fan as the issue.....
This is where it gets weird. When you unscrew the fan casing (but obviously leave the earth connected) the fan works and it doesn't trip. Once I bolted the fan back on, the electrician said the fan was "slowly showing the fault again". This obviously indicates a fault with the fan so I bypassed the internal power leads from the PCB to the fan thinking there may be a short there - nope, still trips....
Now I know this is dodgy (but I have been without heating for 5 days and have 2 young kids) - I used ptfe tape on the self tappers securing the fan case to the boiler to insulate it from the casing and it works OK for the time being?! I tested for continuity from earth on the fan (this is directly to the motor) and the casing, and there isn't any as there are rubber bushes. It is running now as described, but I will re-iterate that the motor is still wired up with the earth connected!
How on earth can the case to the motor be causing the consumer unit to trip when effectively it isn't forming a circuit with anything and forms part of the boiler case when attached?
If anyone has any idea I would be eternally grateful as I don't want to have to replace such a (previously!) easy to work on and simple boiler.....
Thanks.
After a powercut, the boiler would cause the MCB in the consumer unit to trip after a few seconds. It is fine up to the point where the timer box would click and when the fan usually comes on. Due to this I unplugged the fan. The water pump upstairs comes on and it didn't trip. I even blew into the pressure switch and it would start to function as normal i.e. sparking and lighting boiler indicating the PCB was probably OK.
I bought a reconditioned fan and it did the same. After getting a British Gas engineer round, they said it was probably the PCB after doing similar tests to me.
I bought a reconditioned PCB and it does EXACTLY the same...... :disappointed:
The electrician was called in to check the circuit and it is all working fine until he checked the circuit the boiler is on. He said there was a neutral/earth fault reading and hence the tripping on the consumer unit. When I disconnected the fan it was OK, once again showing the fan as the issue.....
This is where it gets weird. When you unscrew the fan casing (but obviously leave the earth connected) the fan works and it doesn't trip. Once I bolted the fan back on, the electrician said the fan was "slowly showing the fault again". This obviously indicates a fault with the fan so I bypassed the internal power leads from the PCB to the fan thinking there may be a short there - nope, still trips....
Now I know this is dodgy (but I have been without heating for 5 days and have 2 young kids) - I used ptfe tape on the self tappers securing the fan case to the boiler to insulate it from the casing and it works OK for the time being?! I tested for continuity from earth on the fan (this is directly to the motor) and the casing, and there isn't any as there are rubber bushes. It is running now as described, but I will re-iterate that the motor is still wired up with the earth connected!
How on earth can the case to the motor be causing the consumer unit to trip when effectively it isn't forming a circuit with anything and forms part of the boiler case when attached?
If anyone has any idea I would be eternally grateful as I don't want to have to replace such a (previously!) easy to work on and simple boiler.....
Thanks.
