Halstead Best 50 - not firing up

[lenseman]

I am round at a house of a young lady in Sussex and she has been without central-heating or hot water for 2 weeks! I have sorted the hot water using the electric immersion heater (on for 2 hours a day).

Removed covers and notice that the Halstead Best 50 has a fan which does not start when the call for HW or CH.

The boiler clicks but the fan does not turn hence no air pressure for the diaphram valve to start the gas supply and ignition.

A quick check reveals that the two black wires feeding the fan have only 150 volts AC which is there immediately there is a call for HW or CH.

Is this the correct voltage or does the fan only require 150 volts? If the fan is 250 volts which I suspect,what might bee the cause of this low supply voltage to the fan?

All stats have been set to Max and no safety buttons or cut-outs switches have been tripped.

I am a marine engineer not a gas boiler man.

Thanks in anticipation sitting is a very cold house in Crawley!

 

[Dan Robinson]

Check the fan wiring.

And also check for 240V at terminal 8 of the ignition control board. If not then change said controller.

 

[lenseman]

Hi Dan, thanks for the reply.

Went back to recheck the voltages and the 150 volts to the fan had disappeared!

I then checked the voltages across Pin 11 and Pin 8, no volts??

I removed the controller and lifted off the plastic covers and found that the pcb was badly scorched around Relay 1 which controlled the fan supply voltage. Also R4 was loose and had dry-joints on each end with the printed circuit track lifted.

Removed R4 (19K Ohms) and replaced it on the other side of the pcb and used a paperclip to replace missing copper track.

Refitted the controller panel, re-fitted all wiring and switched on.

Danfoss CH circulating pump kicked in followed by the flue fan and then we had ignition.

Central heating is now fully operational

Thank you very much for responding to my initial cry for help and Elaine and the cats are very happy and they thank you very much (miaow, miaow).

Best regards David

 

[Dan Robinson]

Glad it's working - working... I wouldn't rely on it staying that way for long, so get a new controller next week.