New Thermostat Question
I have this furnace in my TC.
There are only two connections to the thermostat, and they are labeled “Thermo” and “+Thermo”
I’m installing a new thermostat, and it’s connected like this. G is connected to G, and W is connected to W.
Both the AC and furnace work as they should. The issue I’m wanting to resolve is the FAN switch on the t-stat doesn’t turn the furnace fan on when it’s in the “On” position. It behaves as if the FAN switch is always in “Auto”. I would like to be able to manually turn on the furnace fan, if that’s possible. I don’t need to control the AC fan manually.
The original t-stat was a mechanical type, and I can’t remember if it had a fan Auto/On switch or not. I suspect it didn’t. I replaced the mechanical stat many years ago with a RiteTemp digital programmable model. The new t-stat had the ability to wire the fan Auto/On switch so that it would function as a Hi/Lo switch, which I did. The AC has a two-speed fan, but the furnace doesn’t. I found that I never used the High fan speed though, because the AC will freeze us out on low.
The buttons on the RiteTemp have gotten difficult to use, and we never use the programmable function of it, so I’ve replaced it with a non-programmable model.
The way this was all installed by Lance, is the “Thermo” and +Thermo” wires, that are clearly labeled on the furnace pigtail, were run to the wall t-stat location. I’ve verified with a VOM that the two blue wires in this plug:
Are these two wires behind the wall t-stat.
As you can see, they aren’t connected to the t-stat. They are connected to the pink and purple wires in the 8-wire cable, which runs up to the roof AC. I assume they run through a relay in the AC to prevent the furnace and AC being turned on together.
Is there a way to wire the furnace to the wall t-stat so that the Fan Auto/On switch will turn the fan on manually?
:):)
There are only two connections to the thermostat, and they are labeled “Thermo” and “+Thermo”
I’m installing a new thermostat, and it’s connected like this. G is connected to G, and W is connected to W.
Both the AC and furnace work as they should. The issue I’m wanting to resolve is the FAN switch on the t-stat doesn’t turn the furnace fan on when it’s in the “On” position. It behaves as if the FAN switch is always in “Auto”. I would like to be able to manually turn on the furnace fan, if that’s possible. I don’t need to control the AC fan manually.
The original t-stat was a mechanical type, and I can’t remember if it had a fan Auto/On switch or not. I suspect it didn’t. I replaced the mechanical stat many years ago with a RiteTemp digital programmable model. The new t-stat had the ability to wire the fan Auto/On switch so that it would function as a Hi/Lo switch, which I did. The AC has a two-speed fan, but the furnace doesn’t. I found that I never used the High fan speed though, because the AC will freeze us out on low.
The buttons on the RiteTemp have gotten difficult to use, and we never use the programmable function of it, so I’ve replaced it with a non-programmable model.
The way this was all installed by Lance, is the “Thermo” and +Thermo” wires, that are clearly labeled on the furnace pigtail, were run to the wall t-stat location. I’ve verified with a VOM that the two blue wires in this plug:
Are these two wires behind the wall t-stat.
As you can see, they aren’t connected to the t-stat. They are connected to the pink and purple wires in the 8-wire cable, which runs up to the roof AC. I assume they run through a relay in the AC to prevent the furnace and AC being turned on together.
Is there a way to wire the furnace to the wall t-stat so that the Fan Auto/On switch will turn the fan on manually?
:):)
