240v Single Pole baseboard heater - thermostat wiring

[JDLang76]

Im a DIY novice. I have changed central AC thermostat, light fixtures, switches etc. This has me stumped.

I have a 240v single pole baseboard heater with an old mercury thermostat. I would like to replace that thermostat with a Honeywell TL8130A.

Question 1 - Can someone explain the wiring to me? It is my understanding that voltage should come from the breaker to the thermostat and then additional wiring should deliver that voltage from the thermostat to the heater. However, there are 2 lines in the wall. Each line is hot with 120v when the system is at 40 degrees and inactive. When using a volt meter with each wire/ground, they read 120v. When reading them together. they read 240v. I don't understand how this wiring setup works.

Question 2 - Can I use that Honeywell thermostat? It is single pole, but has 4 wires.

Any detailed explanation of this wiring situation would be deeply appreciated. Honeywell was not able to help.

 

[Megawatt]

Im a DIY novice. I have changed central AC thermostat, light fixtures, switches etc. This has me stumped.

I have a 240v single pole baseboard heater with an old mercury thermostat. I would like to replace that thermostat with a Honeywell TL8130A.

Question 1 - Can someone explain the wiring to me? It is my understanding that voltage should come from the breaker to the thermostat and then additional wiring should deliver that voltage from the thermostat to the heater. However, there are 2 lines in the wall. Each line is hot with 120v when the system is at 40 degrees and inactive. When using a volt meter with each wire/ground, they read 120v. When reading them together. they read 240v. I don't understand how this wiring setup works.

Question 2 - Can I use that Honeywell thermostat? It is single pole, but has 4 wires.

Any detailed explanation of this wiring situation would be deeply appreciated. Honeywell was not able to help.

First off if it’s 240vac it will be a double pole breaker and do you have the paper work of the new Thermostat. I really think you should call a qualified electrician to help you with this project. We would like to see a picture of the electrical requirements and wiring diagram.

 

[JDLang76]

First off if it’s 240vac it will be a double pole breaker and do you have the paper work of the new Thermostat. I really think you should call a qualified electrician to help you with this project. We would like to see a picture of the electrical requirements and wiring diagram.

Then why is the current thermostat single pole? I live in a very small town. There are no electricians. I dont have a wiring diagram. Thats the problem. Im looking for someome to gove me a clue how this is wired.

 

[Megawatt]

Then why is the current thermostat single pole? I live in a very small town. There are no electricians. I dont have a wiring diagram. Thats the problem. Im looking for someome to gove me a clue how this is wired.

The only reason I can give you is 1 phase goes directly to the heater and the other phase is controlled by the thermostat. Having said that you will have 240vac to the heater when the thermostat closes

 

[telectrix]

maybe get some info here:

Honeywell TL8230A1003 | Thermostat Line V Digital 208-240 V | 6WY24 | Raptor Supplies United Kingdom

Thermostat Line V Digital 208-240 V | 6WY24 | Delivery to the UK and Channel Islands | 0203 287 5224 | [email protected]

www.raptorsupplies.co.uk

as the thermostat needs 240V i imagine you'd use both hots as feed to the stat. then the other 2 wires will be from boiler (IN) and back to boiler (OUT) across the stat's volt free relay. this allows switching of 240V or 24V , whatever the boiler wants.