Ok, heating engineer has been and gone, 2 year old gas boiler at fault and now the manufacturer is coming tomorrow to have a look while we all shiver again. What time are they coming, anytime between 7.00am and 6.00pm, just glad that we aren't yet in the depths of winter
FWIW I had a gas hot air furnace go out recently. Before I made a 3 hr trip to pick up a $320 board I decided to take a 2nd look. A 47 uF, 63 V cap was obviously blown. So I pulled the board and took it home. After a lot of rummaging through parts bins, I found some 22 uF, 100 V units, so I wired them in parallel pairs and it was fixed at less than 1/2 the drive time and none of the cost.
After looking at the previous furnace board I had replaced (at another commercial property) which had 1x 22 uF and 2x 47 uF caps, I ordered 100 each of higher reliability Nichicon 22, 47 & 100 uF at 63 V. Aside from 2-3 $0.25 caps, everything is semiconductors, resistors and relays. So it is quite unlikely that anything other than bad caps and ESD will kill a board.
Amazingly, the OEM caps are just regular SMPS caps, not one of the "high reliability" parts.
Reg