Coleman Presidential III LP Gas Furnace
Intertherm A/C unit (split system)
Furnace Model No: 7956-856
Serial No: 058774442
Is this furnace supposed to work with only two wires connected to the thermostat? Only 18/2 connected to stat, and I have to turn the main On/Off switch (at furnace) to ON to get it to run for Heat or Cool, while also using the HEAT/COOL rocker switch on the right side of upper control box, with the left side rocker (CONT/AUTO) set to AUTO.
Thermostat is Honeywell digital with jumper between Rh & Rc, red wire is attached to Rh, white wire is attached to W .
Dont know if this helps, but have a pic (can get more if needed):
The small transformer you see on top of the control box belongs in the box below, that covers the 120v connections to the main ON/OFF switch and goes out to that transformer and a couple of fan (limit?) switches on the right side of that box. That transformer has no continuity between the load side terminals and was getting ready to replace it, when I discovered that the A/C would still work - it's getting voltage from the transformer in the upper control box (pictured).
There is one set of 18/2 feeding the wall thermostat and another set feeding the contactor on the outdoor A/C unit. Yellow and gray ( I believe) feed the contactor.
Does Coleman provide manuals/wiring diagrams? Thx much for any help.