Top honeywell st9120c4057 wiring diagram - With thermostat heat/off/cool transfer set to heat, and fan car/on switch set to car, warmth runs typically: internal blower/fan is off, fuel valve activates, furnace ignites. After some put off, blower starts and runs normally. Then, set thermostat warmness/off/cool switch to off. Fuel valve turns off, blower continues to run for some time, then blower shuts off. Trying out: first i placed a jumper from g to r and depressed the interlock transfer to allow strength to the device. After a very quick postpone (about one-1/2 to 1 2d), the interior blower/fan started up. I checked the voltage on the warmth terminal and located a hundred and twenty vac.
I established the blower/fan wiring and it became as tester101 said: a black cord became at the cool terminal. The black wire runs the blower on excessive velocity. A blue cord was on the warmth terminal. The blue twine runs the blower on medium velocity. A purple twine was at the m1 terminal. The pink cord runs the blower on low pace (lowest speed). With thermostat warmth/off/cool transfer set to chill, and fan automobile/on switch set to auto, outdoor ac fan and compressor begin and run generally, inner blower by no means starts offevolved. Whilst outdoor ac fan and compressor are running, turning fan car/on switch to on has no effect (internal blower remains off).