Suburban furnace

[Gunner80]

So I did the dumb thing and passed under something and tore up my rooftop a/c. I removed the old a/c unit and installed a split a/c unit. Man… talk about an upgrade! Anyway, winter is coming and it’s getting cooler. My question is what wires are used to control the furnace and how can I install a thermostat? didn’t think much when removing all the wiring and thermostat and tossed them.

 

[Gary RV_Wizard]

Get a simple heat-only thermostat, something like this. It requires a small amount of 12vdc power from any convenient source plus a single output wire to the furnace itself. The furnace will have a terminal to receive the thermostat wire, which triggers the furnace to start the heat cycle. The furnace has its own higher amp 12v power, so the wire from the thermostat only supplies a trigger voltage to kick it on.

Download the manual for your Suburban if you don't have it to identify the connection for the thermostat trigger wire.

 

[John From Detroit]

On most Furnace/AC systems the furnace supplies 12 volts to a wall mounted T-Stat.. and the Stat controls the A/C with a switch closure
Now Carrier the Thermostat was part of the A/C and a pair of blue wires ran up to the A/C from teh furnace one was 12 volt the other the wire that signaled the Furnae "Make heat" inside the A/C control box was a smipe relay so electrically it looked like this.
12 V from furnace _______/ _______ back to furnace OFF
12 V from furnace _______________ back to furnace Heat
So what I did when I replaced the Carrier
I got a 20 dollar Mechanical T-Stat from ACE hardware (Pick it up today not delivered next week)
This is a basic switch with a bi-metal spring and a couple of other things (Anticipator adjustment and heater. You really don't need to knwo. Set to max or min whichever works best) and a magnet to provide some "Delta" between turn and turn off and make sure it "Snaps" open/closed.
No need to make sure it's level will work at any angle.
And it matters not which screw gets the "hot" wire (The one with 12 volts all the time)
Worked great.. Better than the original in fact.

 

[Isaac-1]

Suburban furnaces use a pair of blue wires, when connected they turn on the heat

 

[John From Detroit]

Suburban furnaces use a pair of blue wires, when connected they turn on the heat

Same for Attwood... one wire carries 12 volt FROM the furnace to the T-Stat. the other returns it to fire the sucker up. Some T-stats need a ground (pick one up anywhere) so their electronic work but the el-cheap-o that I got at ACE.. Simplest one they had. Does not.. Worked very well I might add.

 

[Kirk]

Get a simple heat-only thermostat, something like this.

That thermostat is a very good choice but it does not require any source of outside power. The furnace has 2 blue wires and one has 12V applied and the other tells it to start heating when they connect together. Just connect one blue wire to one side of the thermostat and the other blue wire to the other side and when it calls for heat the thermostat closes to connect them and when it reaches the proper temperature it opens them and the furnace will cool down and stop.

You could also use any of these thermostats which work exactly the same way as the Suburban.
Dometic ~ ~ Emerson ~ ~ Honeywell

 

[SuwanneeDave]

So I did the dumb thing and passed under something and tore up my rooftop a/c. I removed the old a/c unit and installed a split a/c unit. Man… talk about an upgrade! Anyway, winter is coming and it’s getting cooler. My question is what wires are used to control the furnace and how can I install a thermostat? didn’t think much when removing all the wiring and thermostat and tossed them.

Isn't the new system a heat pump that can provide heating?
Also I am curious how it was installed if you could post some pictures.