Help with Wiring a Thermostat (to 2 electric baseboards)

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Old 12-14-20, 12:17 AM
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Help with Wiring a Thermostat (to 2 electric baseboards)

I need some help with a 240V baseboard heater problem...

I bought two smart thermostats for my home. I installed the first one and it powered on as soon as I flipped the breaker back on. Turned the breaker back off, and installed the second one. Flipped the breaker on and it worked too - yay for the rookie DIY electrician! But, wait - I went back and looked at the first thermostat, and it was no longer powered on. I turned the power off again, checked the incoming feed and there was no current flowing through it.

I then went back to the second thermostat and noticed it had one extra pair of wires... I didn't notice this when I installed it and connected everything per Mysa's instructions - as if the thermostat was controlling three baseboards (it only controls two). Now I'm thinking this is the cause of my problem at the first thermostat location, but I have no idea how to fix this. Any help would be appreciated!

Each thermostat is controlling two baseboard heaters and they are connected as per the attached diagram (except for the extra pair of wires on the one which was connected as if it was a third baseboard).



Thanks!
 

Last edited by rickparsons; 12-14-20 at 12:54 AM.
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Old 12-14-20, 01:34 AM
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Welcome to the forums.

That's a lot of wires in a box with a thermostat. You need to stop and think what you've done.
You have a box with four cables....
1) power in
2) power out to second stat
3) power out to baseboard
4) power out to baseboard.
You treated #2 - power out to second stat as a third baseboard heater. That's wrong.
You should have two power cables tied together and two baseboard cables tied together.
 
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Old 12-14-20, 09:55 AM
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Thanks Pete... I totally agree... However, how do I determine which pair goes to the second stat? I was able to determine the power in, but I have no idea how to determine the power out to the second stat.
 
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Old 12-14-20, 10:15 AM
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Connect one cable at a time to the live one until you locate the second thermostat location.
 
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Old 12-14-20, 01:15 PM
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Thanks, Pete. So, just so I'm clear, I currently have one wire (black "line") connected to the "line" wire on the stat, and the other three black wires are connected to the stat's "load" wire. All four red wires are connected to the L2 wire on the stat. I should be taking one black wire at a time off the "load" wire and connecting to the "live" wire, leaving all other wires where they are, until I find the one that powers the second stat, correct?

Thanks again!
 
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Old 12-14-20, 01:17 PM
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Since you are testing for voltage...... leave all the red wires connected.
I would take all three wires off of the load and check them one at a time.
 
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Old 12-14-20, 08:29 PM
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Thanks for the help, Pete. Everything is up and running properly now (of course, it was the last of the wires I tested )
 
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Old 12-14-20, 09:23 PM
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Good job. Back in heat again.
 
 

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