After hours service call , furnace repair . Cycled power and watched furnace operator for 20 mins no issues . Customer mention the hydro company had power off to the house short before furnace failed . Filter is a 6672( 5 inch filter about 10 months old ) furnace is operating with a 70 split . After cycling furnace off and back on with main power (120v ) multiple times the furnace did not come back on one of the times with 27 v going to terminal w and no error codes . If problem persist replace circuit board or furnace .installed new filter 6670 .