(System is straight cool, 10KW 1-stage heat.) Just installed this variable speed air handler with a matching 12-SEER Am Standard condensing unit. All works well in cooling mode (soft start, 1/2 speed for 7 1/2 minutes, etc.)but air handler will not start in heat mode. Wired correctly, has 24-volts at the W-1 terminal, but the heat contactor will not pull in and the blower motor sits idle. Passes all tests using the factory "Trouble Shooter" circuit board and 4-wire test cable, and all connections/connectors appear to be well made. When a jumper is momentarily connected from the common side of the heat contactor to the common on the low-voltage terminal board, the contactor pulls in (but the blower remains idle). Anyone had a similar problem...fix?