Is this 220v thermostat available?


Old 09-25-07, 06:02 PM
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Is this 220v thermostat available?

A family member added a couple electric baseboard heaters to the existing ones in the family room, for the upcoming winter. The old setup is fed at the line voltage thermostat with 12/2. According to my calculations, your allowed to put 3,840 watts on a 20 amp 240 volt 12/2 circuit. A second 12/2 line would satisfy the two extra heaters. Anyway, I was wondering if there is any type of thermostat I can buy at a supply house, that would operate two seperate circuits with one control. Basically, I am trying to get around putting two thermostats to control the same room.
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Old 09-25-07, 06:14 PM
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There is couple thing to get you corrected on this matter,..

the electrical caluations you have it came up wrong the 20 amp circuit at 240 volts is 4800 watts.

but for baseboard heater you can run that much but really normally most run up to 80% of the line rating which 3480 watts [ @ 240 volts ]

what the total wattage on the oringal baseboard heater and the wattage of new baseboard heater ??

to run two seperted circuits to one thermoast is not very festable idea at all for few reason one is may not have engouh room in the junction box if this is on the wall mounted thermosat.

second thing that if you get two circuits in the box and if not carefull you can actally get the line crossover and either heater will not come on or short out depending how it done in the box.

but if the thermosat at the heater itself that little diffrent story there until i know more details we in this forum can steer ya in right direction there

Merci , Marc

P.S. there is other option is that can used the " power relay " or contractor swiching device can handle this much load as well
Old 09-25-07, 11:05 PM
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Fixed electric space heating has to be calculated as a continuous load. I believe a 20 amp 240 volt circuit will max out at 3840 watts for continuos loads. Anyways, I know the circuits I need to satisfy this, there is 6000 watts of heat. The thermostat is wall mounted and I have no problem replacing the box if it goes over wire fill calculations.

In a residential application, I believe 30amps is the biggest circuit you can run to a heater. You can run 50 amps in a nonresidential application. I know electric heat isn't the most efficient heat, but there has to be somewhere that someone has more then one 30 amp line heating a huge room. I figured there would be a thermostat designed for this purpose so you don't need to adjust two thermostats for the same room.
Old 09-26-07, 05:22 AM
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Electric heat is the most efficient heat you can buy for your home. It is near 100 percent efficient. This is more efficient than even the best natural gas or oil furnaces.

The problem is that electricity is more expensive than oil or natural gas when it comes to the energy required to produce the heat.

In a residential setting, the accepted practice is to separate the baseboard heaters into sections of the room, with a thermostat in each section. My last house had a setup like this for the living room and dining room.

If you really want a single thermostat, then you need to use a low voltage thermostat that can trigger relays for several 240 volt lines.
Old 09-26-07, 08:32 AM
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Although electrical resistance heating is indeed 100% efficient (i.e., they produce one unit of thermal energy for every unit of electrical energy they consume), electric heat pumps are more than 100% efficient (i.e., they produce more than one unit of thermal energy for every unit of electrical energy they consume). They get the extra energy from the thermal energy in the outside air.
Old 09-26-07, 09:52 AM
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Automatic control of two 240 volt circuits can be effected with a 24 volt control-power transformer , a heating thermostat , and two 2-pole contactors with 24 volt operating-coils and contacts rated at 30 amps.

You can set the contactors in a metallic enclosure , available at an electrical supply house . The components for the "control system" are available at an HVAC supply house. Don't waste time at a Home Depot .

It's possible with a Heating-Cooling thermostat to also control window AC units in the same room area that is heated electricaly. This requires another contactor for switching the circuit to the receptacle where the AC unit connects.

Good Luck & Learn & Enjoy from the Experience!!!

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