When switch on the boiler does not fire up, but a clicking noise coming from the circuit board; this clicking noise is coming from the relays on the board, trying to set (but instead of click and set continuously trying to switch) . This clicking is continuing (and boiler does not fire up)until the boiler is completely switched off. I can see the SG1 firing inside (blue spark ). The fuse is fine, no visible burnt out parts etc. and no dry joints on the board. I think the noise is one of the relays is trying to set but it does not happening. (The boiler starts with a big click when switched on, and a fan or a motor starts running but does not getting fired up). I believe something wrong with the circuit board.
I would be very grateful to you, if you could please let me know which parts may be required to be replaced or whether the problem is with the circuit board ( and whether the Circuit board needs to be replaced, or what else I need to be checking)?
With thanks and regards, DY
PS: Boiler is Potterton Netaheat 10/16 Electronic and the circuit board (Boiler Control) type no is 407676.