Thermostat replacement

[bobblangley]

I have a 1994 Bigfoot 17' Gaucho trailer with the original thermostat for the heater and would like to switch out that thermostat for a digital thermostat. Most thermostat wiring I've worked with in the past consists of several thin wires that attach to color coded terminals. The existing wiring in the Bigfoot consists of 2 fairly thick red wires. Can anyone tell me where to connect those two wires to the new thermostat?

[Glenn Baglo]

I installed a Honeywell digital thermostat and there was a piece like that red wire. Its purpose was to connect those two contacts for my type of application.

The black and white wires from the furnace also have to be connected to the thermostat.

You should find installation instructions with the thermostat you purchase.

[bobblangley]

Thanks for the input. There is already a furnace installed and there are only two red wires attached to the existing manual thermostat works well which leads me to believe that those are the only wires that actually need to be connected to the thermostat.

I am hopeful that connecting those two red wires to some combination of the "C", "W", "Y", "G", "B", or "O" terminals on the new thermostat will lead to similar function. I just have no idea which of those six terminals might work.

[Glenn Baglo]

You need to read the instructions for the new thermostat. It tells you what to connect to what.

[bobblangley]

The new thermostat has minimal instructions; basically just a diagram with the following labels -

"C" = 24-v operation
"W" = heat relay
"Y" = cool relay
"G" = fan relay
"B" & "O" = changeover valve
"RC" & "RH" = power supply

The existing manual thermostat is connected to two red wires coming out of the wall of the trailer behind the thermostat. The existing furnace (no AC) works fine with just those two wires connected to it.

[Glenn Baglo]

Had a look at my instruction manual and it say to label the wires before removing them from the old thermostat. To my recollection, I used that jumper ( the red wire you have shown ) between the contacts.

Then I connected the thin wires from the furnace to the same points as on the old one. I don't have any air or heat strips, so mine was just a simple swap.


Go here:
https://www.wikihow.com/Install-a-Digital-Thermostat

[David Tilston]

If I read the web site correctly:
T21STK-2_SASWELL


You have a thermostat designed for home use. It requires 20VAC to 30VAC. You probably can't use this in your trailer.

[Casita Greg]

Originally Posted by bobblangley

The new thermostat has minimal instructions; basically just a diagram with the following labels -

"C" = 24-v operation
"W" = heat relay
"Y" = cool relay
"G" = fan relay
"B" & "O" = changeover valve
"RC" & "RH" = power supply

The existing manual thermostat is connected to two red wires coming out of the wall of the trailer behind the thermostat. The existing furnace (no AC) works fine with just those two wires connected to it.

You need a 12 VDC T-stat. A 24 VDC one won't work for your trailer.

EDIT: Sorry, didn't read Dave's post before I replied. His basically says the same thing...

[stevebaz]

Does the new thermostat have a battery to power the display?

[stevebaz]

My white rodgers thermostat,
jumpers short red wire rh to rc.

Control leads from heater, white wire on rc with the red jumper and the other control lead red wire from heater on w

My lcd display power comes from 2 AAA batteries.

[bobblangley]

Powered by a battery.