My problem is with a Halstead Best 60 boiler which was previously working fine for 5 years, but now has a problem with ignition. 230v supply is OK and switched 230v supply is OK. Fan working freely and flue free from blockages.
So here we go: Sometimes the boiler lights and burns for 5-20 secs before cutting out. Sometimes the relay clicks and the fan runs for 2-3 secs before cutting out. MOre and more, the relay clicks twice and nothing else happens - this takes place in a continuous cycle every 15 secs for hours at a time.
The fan seems to be running freely, there flue is clear, the solenoid is sparking fine and there are no neon warning lights. I think the problem lies with either the ignition control unit or the aquastat/potentiometer/thermistor. I have done some voltage testing as recommended in the instruction manual and have come up with an interesting result which I think should enable me to diagnose the problem, but I don't know how to interpret it - hope you can help.
ON the (pink) connection between the aquastat PCB and ignition control unit there should be either 1V or 10V DC according to the manual. A reading of 1V would indicate that the aquastat PCB / thermistor / potentiometer is faulty; a reading of 10V would indicate that they are fine. Trouble is, I'm not getting either. At the beginning of the 15 sec cycle, I get a reading of 4V DC for 7 secs, rising gradually to 35V DC over the next 8 secs. Then there's a clisk and the reading drops back to 4V DC.
Basically, can anyone tell me what this means? I'm inclined to guess that the ignition control isa at fault since that's where you'd expect a charge to build up for the solenoid. But basically I don't know
So here we go: Sometimes the boiler lights and burns for 5-20 secs before cutting out. Sometimes the relay clicks and the fan runs for 2-3 secs before cutting out. MOre and more, the relay clicks twice and nothing else happens - this takes place in a continuous cycle every 15 secs for hours at a time.
The fan seems to be running freely, there flue is clear, the solenoid is sparking fine and there are no neon warning lights. I think the problem lies with either the ignition control unit or the aquastat/potentiometer/thermistor. I have done some voltage testing as recommended in the instruction manual and have come up with an interesting result which I think should enable me to diagnose the problem, but I don't know how to interpret it - hope you can help.
ON the (pink) connection between the aquastat PCB and ignition control unit there should be either 1V or 10V DC according to the manual. A reading of 1V would indicate that the aquastat PCB / thermistor / potentiometer is faulty; a reading of 10V would indicate that they are fine. Trouble is, I'm not getting either. At the beginning of the 15 sec cycle, I get a reading of 4V DC for 7 secs, rising gradually to 35V DC over the next 8 secs. Then there's a clisk and the reading drops back to 4V DC.
Basically, can anyone tell me what this means? I'm inclined to guess that the ignition control isa at fault since that's where you'd expect a charge to build up for the solenoid. But basically I don't know
