Installed an Aprilaire humidifier model 700 with a model 56 Humidistat Wiring is: correct, verified several times. Both Outside and inside sensors read okay. HH goes to Humidifier (24VAC when unit is plugged in) RC go to furnace W and 24 VAC common) and reads 24VAC when furnace is running, ODT go to outdoor sensor Plugged in the unit to 110 and both the Green and Red lights came on briefly then turned off. Dial set at 7 outside temp is 24F Humidifier only runs when in the test position with either outside or inside resistor and in auto or manual mode. Could the model 65 circuit board be bad? How to verify? Any assistance appreciated

Humidifiers - Aprilaire - 700 Humidifier