Background: Have posted a few times regarding Prima 50F reigniting for no reason intermittently. Many helpful suggestions, but 18 months later no further forward. Until now ...
So, Sunday afternoon, the boiler refused to fire. Pilot flame burning, but no voltage on the main burner control valve. Relay for main burner not firing. Fixed 407677 control board (I'll spare the details lest those that make money from these repairs complain!). Still reignites maybe once per day, but running perfectly otherwise. Total cost: 35p ;-)
Obtained new control board as a backup. Looks fine (layout a little different), basic checks OK. Best test it ... Remove working control board, install new one. Fan won't run :( Install old one - Everything works. Install new one - Fan starts and stops every few seconds :/
Will return the 'new' board to the vendor, but I'm astonished that a BNIB board is broken. And here's the rub ...
I remember about 5 years ago the guy that repaired the boiler said that there was a 'wiring problem', and that he had to replace the control board and 'fix' the wiring. I'm starting to think that the wiring problem may have been a neutral/earth switch! 8-/
I'm loathe to return the new board as I'm sure it's fine. I just need to find what witchcraft there is in the wiring to the boiler. I'm getting an ohm between the boiler chassis and local earth - Seems high to me.
Ideas?
Al.
p.s. There were 2 faults on the original control board. One minor, the other fatal! I guess I should post the details. Maybe not.