How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Mike G. Your Own Question
Mike G.
Mike G., Master Electrician
Category: Electrical
Satisfied Customers: 7654
Experience:  Proven Professional 48 years Experience
Type Your Electrical Question Here...
Mike G. is online now
A new question is answered every 9 seconds

I have an old Honeywell Thermostat that stopped working.

Customer Question

Mike - I have an old Honeywell Thermostat that stopped working. There is only a black wire and a white wire in the hallway box. No Ground - just a white and black wire. Not sure if both have power or not. The black definite does. I bought a Marley 602W 240 it has 2 blacks and 2 reds. what do I attache my white wire to and my black wire to on this new thermostat?
its line voltage...
Submitted: 1 year ago.
Category: Electrical
Customer: replied 1 year ago.
Also, on the old Honeywell, the black wire was on the "Comm" screw and the white wire was on the "Heat" screw
Expert:  Mike G. replied 1 year ago.

Hi, I'm Mike G and I'll be assisting you. You purchased a 2 pole t-stat for a single pole installation. No matter it will work. Just terminate the wires on one side, top and bottom. Cap the unused ones.

Customer: replied 1 year ago.
Hi mike. Since the back of the t-stat is covered I can not see where the wires go -the wires come out of the back for left to right black, red, red, black. So I figure I'll watch the two on the left, black and red. I'll cap the black and red on the right. Do u think the black in my box has power and the white it the neutral? So I'll attach black to black and white to red.
Thanks! I know it's a holiday :)
Customer: replied 1 year ago.
Sorry for the typos! i just looked at the t-stat and I can see a black and red on each "side" so yah think black to black and red to white right?
Expert:  Mike G. replied 1 year ago.

Happy Thanksgiving to you. The wires are a hot and a switched hot, no neutral. They should have marked the white with black tape when installed. What it is, is that they break one of the hot lines for a T-stat. Common practice. Your new device is when they break both lines.

Customer: replied 1 year ago.
Ok I ready to hook it up, thanks. I'll give ha 5 stars once I hook it up. In 30 kids running around! Kathleen
Expert:  Mike G. replied 1 year ago.

Take your time, no hurry.