Vitodens 100W Power Pump Module Failure

Beaver33

The fan and boiler are now operational!

The high voltage capacitors, optoisolators, gate drivers, offline switch and transistors were replaced in the fan.

I believe the problem originated with a shorted MOSFET in the fan that caused a power surge. The surge in turn damaged another component(s) on the fan board, blew the fuse on the control board and damaged 2 resistors on the power board.

I want to thank @GGross and especially @109A_5 for their assistance in the repair.

GGross

I have to say I am thoroughly impressed with the efforts put forward by both you and @109A_5

109A_5

Hello @Beaver33,

Excellent news !!! You have gone where few go and WON !!!

Beaver33 said:

I believe the problem originated with a shorted MOSFET in the fan that caused a power surge.

Possibly the cause of the original failure, but I have my doubts. It seems like an input power over-voltage situation to me. With the original shorted MOSFET not blowing the internal (to the motor assembly) 2 Amp fuse I doubt any reactive surge would do that type of damage to the resistors.

I would suspect Lightning, power utility antics, or a service entrance neutral wire issue.

I think I would put a good quality surge suppressor on the boiler's branch circuit. Or your own MOVs in a metal box. Metal box for MOVs they are known to start fires. It may be cheap insurance to avoid a repeat performance.

Anyway good to hear you are up and running, its getting cold out (at least here), with any luck it will never happen again.