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Old 01-03-2009, 05:02 PM   #1
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Thermostat for electric baseboard heat 4 wire to 2 wire


I am replacing my old Honeywell CT60B with a new programable Honeywell.

The old stat has two black and 2 red wires, the new one has 2 black. I think I should connect the 2 reds together and the 2 blacks will be wired to the stat.

Is this correct? How can i test to make sure I'm doing it correct. (FYI I have a volt meter)

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Old 01-04-2009, 07:41 AM   #2
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Thermostat for electric baseboard heat 4 wire to 2 wire


I thought code reuired the stat to open both legs on line voltage heat controls.

Personally, I won't install a 2 wire line voltage stat.

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Old 01-04-2009, 12:50 PM   #3
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Thermostat for electric baseboard heat 4 wire to 2 wire


Assuming your city's code allows single pole (2 wire) electric heat thermostats, start with all four wires disconnected. Only one pair combination will register voltage (usually 240 volts) when you test using your voltmeter. To double check, the pair that registered voltage should come from the same cable entering the back of the wall box.

Turn off the power again.

Tie together one wire from the pair that registered voltage and one of the other wires. Connect the other wire from the pair that registered voltage together with the other remaining wire to the thermostat.

OT: As far as double pole thermostats go, it is not unusual for one of the poles to make/break at a different temperature from the other. Your own calibration may be needed. This sometimes requires scraping glue or paint from the adjusting screws and putting fresh (or nail polish) back when you are done to hold the calibration.

Last edited by AllanJ; 01-04-2009 at 12:54 PM.
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Old 01-04-2009, 01:10 PM   #4
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Thermostat for electric baseboard heat 4 wire to 2 wire


""OT: As far as double pole thermostats go, it is not unusual for one of the poles to make/break at a different temperature from the other.""


How would you know this is happening??
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Old 01-04-2009, 01:34 PM   #5
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Thermostat for electric baseboard heat 4 wire to 2 wire


Its a safety feature.

Minimizes the chance of both contacts fussing together.
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Old 01-04-2009, 03:02 PM   #6
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Thermostat for electric baseboard heat 4 wire to 2 wire


Should I get a double pole? If it is "safer" I would prefer it. What are the benefits?
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Old 01-04-2009, 04:04 PM   #7
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Thermostat for electric baseboard heat 4 wire to 2 wire


It is safer and meets the electrical code. Replace the one you have with the same kind. If not and there is a fire the fire inspector and insurance company will nail you.
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Old 01-04-2009, 06:25 PM   #8
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Thermostat for electric baseboard heat 4 wire to 2 wire


When set to off.
Now electric is at the heater.
Only one pole arcs when it turns the heater on or off.
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Old 01-04-2009, 06:33 PM   #9
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Thermostat for electric baseboard heat 4 wire to 2 wire


Double pole line voltage thermostats have an "off" position. When set to "off" the thermostat acts as a disconnecting means, and all power to the unit is disconnected.

Single-pole thermostats have a "low" position, but no "off" -- there can be voltage present at the heating unit no matter where the thermostat is set. You always have a minimum setting on these, and the heat will come on at some point during low ambient temperature conditions.
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Old 01-05-2009, 12:18 PM   #10
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Thermostat for electric baseboard heat 4 wire to 2 wire


I installed it last night without a problem. I went back to Lowe's and HD to purchase a 4 wire unit, but they don't carry the programable 4 wire stats



Honeywell sells this for "Contractor Installation" only. I guess due to the 240volt/3K watts issues, I assume you could fry the unit if you hook up the wires wrong.

Today, I did order the Honeywell TL8230a since this is a double pole type (4 wire). It seems like the safer way to go. Found it at a good price at PEX

http://www.pexsupply.com/index.asp

Thank you to all that responded, I probably would have "settled" for the 2 wire if I didn't hear such strong responses about it.
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Old 01-05-2009, 10:05 PM   #11
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Thermostat for electric baseboard heat 4 wire to 2 wire


Your welcome.
And much much better off now.

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