problem with a Honeywell fan control

sheldo

Hi, need help!!  I have a Burnham direct vent gas boiler with a Weil- Mclain gold plus hot water expansion tank .

 The transformer  on the Fan relay assembly, R8285D 5001  burned out. I replaced the assembly only to have the new transformer heat up and burn out in about 30 seconds, right before my eyes (saw the puff of smoke).

Circulator continues to pump cold water through the expansion tank. Of course the boiler never comes on.

There are no visable defects.

thank you.