Help figuring out this line voltage thermostat setup

[vinayco]

Hi,

I bought a house that has a garage that was converted to an office by the previous homeowner, and it is separate from the main house. I suspect that they did some of the work themselves. The office has two baseboard electric heaters, and also an electric heater that blows hot air. Somehow, the same thermostat controls both the electric baseboard heat, and the blower electric heater.

The temperature fluctuates quite a lot in there, so I'd like to replace the thermostat, which is the lowest-end "dial" type where you don't even set a numeric temperature, just put it in the "comfort zone."

However, I pulled off the face plate and saw that it is a "Model MD26" marked "double pole" and behind it I found two pairs of red-black wires plugged into it (for a total of 4 wires; 2 each of red and black), as well as a non-insulated copper wire screwed into the back, which presumably is ground. Here are the photos:





I think this is a standard double pole thermostat setup, but I am not sure, and some confirmation would be much appreciated. I'd like to replace this with a programmable digital thermostat, I found the "Honeywell RLV4305A1000/E1 Rlv4305A1000/E 5-2 Day Programmable Thermostat" which seems to fit the bill - will this be compatible with my setup?

Thanks!
-Vinay

 

[Timbo]

Hi, welcome to the forum.
I would suspect that one pole controls each of your heat sources - one for both baseboard heaters, the other for the blower unit.
You will probably need two Honeywell stats, or fit a double pole relay or contactor.
@Megawatt may be able to advise further as he is USA.

 

[vinayco]

Thanks, Timbo!

My understanding (which easily may be incorrect, this is just from me Googling around) is that double pole thermostats were ones with a proper "off" position, rather than just putting through very little current. This one is listed as double pole so I thought that might be what's going on, but maybe the "double" here really means "controls two things at once"?

Any insight on this is much appreciated, thanks!

 

[Megawatt]

Hi,

I bought a house that has a garage that was converted to an office by the previous homeowner, and it is separate from the main house. I suspect that they did some of the work themselves. The office has two baseboard electric heaters, and also an electric heater that blows hot air. Somehow, the same thermostat controls both the electric baseboard heat, and the blower electric heater.

The temperature fluctuates quite a lot in there, so I'd like to replace the thermostat, which is the lowest-end "dial" type where you don't even set a numeric temperature, just put it in the "comfort zone."

However, I pulled off the face plate and saw that it is a "Model MD26" marked "double pole" and behind it I found two pairs of red-black wires plugged into it (for a total of 4 wires; 2 each of red and black), as well as a non-insulated copper wire screwed into the back, which presumably is ground. Here are the photos:
View attachment 55321

View attachment 55322
View attachment 55323

I think this is a standard double pole thermostat setup, but I am not sure, and some confirmation would be much appreciated. I'd like to replace this with a programmable digital thermostat, I found the "Honeywell RLV4305A1000/E1 Rlv4305A1000/E 5-2 Day Programmable Thermostat" which seems to fit the bill - will this be compatible with my setup?

Thanks!
-Vinay

The Honeywell tsat is a low voltage 24vac device and in the picture that looks like 120vac and I have to agree Timbo the old Tstat probably controls all the heat. If you purchase a Honeywell not sure it will probably operate your heating set up