Service manual

22
12B.1 No Heating; Electric Heat Mode
(Green L.E.D. Light Circuit)
F/FY Circuit Open to The Thermostat
Note:
The green light on the board has some new functions on the 6535 “A” model. If the light is on solid,
everything is OK. If the light is blinking slowly, the unit is in a 3 minute time delay. If the light is blinking fast,
there is either no line voltage to Circuit 1 or one of the thermisters are open. If the light is not on at all there is
no 12VDC power to the thermostat or the PC Board.
Important Notice: If the unit is equipped with a high pressure switch and this switch opens, it
Opens the 12 VDC (-) negative circuit from the thermostat to the P.C. Board
and all heat pump functions are dead. Be sure to correct the root problem causing
the high head pressure. If any heat pump function operates, the switch is OK.