electric baseboard heater low V thermostat


Old 02-08-04, 02:41 PM
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Question electric baseboard heater low V thermostat

I live in New England in a contemporary house that was built in the mid 70's. It has electric baseboard heating with thermostats in each room. I recently had the electric company come out and do an energy efficiency analysis of the house. The results were very good on insulation and general energy efficiency. The thermostats in the house were the old dial type and you could barely tell what temperatures they were set on. The electric company had a deal on replacing them all and I had them all replaced with new digital programmable thermostats for a very reasonable price. I am very happy with the results in each room with the new thermostats.

The living room is the largest room in the house and with high ceilings the most energy inefficient in the house. The thermostat in the living room is a low voltage thermostat. All the other thermostats in the house are line voltage thermostats. When the electrician came to the house to replace all of the thermostats he determined that there was no way that the low voltage thermostat in the living room controlled the baseboard heaters in the living room. He decided that that thermostat was probably not plugged into anything and that the living room must be controlled by one of the other thermostats on the same floor. He therefore refused to replace this thermostat as all of the thermostats he brought for the swap out were line voltage thermostats.

After many cycles of turning on different zones and different breakers I have determined that the living room temperature is controlled by the low voltage thermostat. The heater units in the room are divided up into three different two pole breakers (1 @ 20Amp & 2 @ 15Amp). There are 2-3 heater elements per breaker. I would really like to have a programmable digital thermostat in this room also. Here are my questions:

1. Can I buy any low voltage programmable thermostat to replace this thermostat in the living room?

2. Is this a strange setup to have one thermostat controll electric heaters that are on multiple breakers? I noticed another entry on this forum where someone mentioned this and it seemed to be waived as incorrect just as the electrician that I spoke to.

3. Does this thermostat have transformers or relays to control each of these heater banks?

4. These heaters never seem to be as hot as the ones controlled by the line voltage thermostats. The wall units all look the same. Is this due to the low voltage thermostat?

5. All of the heating elements in the house are Singer brand baseboard heaters. There are 2-3 per room except for the living room which has 7. I am sure they were all installed when the house was built in the mid 70's. Has there been enough progress in the energy efficiency of electric baseboard heaters to think about replacing any or all of these units? Some of the heaters are used much more than others.

Sorry about the novel but I am full of
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Old 02-08-04, 02:53 PM
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It is possible to control heaters on multiple breakers but you would need a multi-pole relay or have one thermostat controlling more than one relay.

You will have to do a little more digging to figure out how this works.

You would do well to call a HVAC tech as an electrician might not be my first choice in dealing with the system you have. A consideration is the operation of the heat anticipator and setting it up properly.
Old 02-09-04, 07:59 AM
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I also noticed the reply on another thread that seemed to state that multiple circuits couldn't be controled by a single thermostat and I don't think that's correct. It doesn't seem like it would be unusual to find this setup when the heating requirment of a single area surpasses the capacity of a line voltage thermostat and a single circuit. The baseboards shouldn't run any differently with a low voltage thermostat and relays than they do with a line voltage thermostat. Do they heat the space comfortably? If not, it might be worth having someone different come out and take a look at the system. There may be a bad relay or other componant.

There are a few new technologies in electric heating, but really no development that would make more heat from less wattage, so it really wouldn't be cost effective to look at replacement of the existing system. Electric heat is and always has been 100 percent efficient (all the heat made goes into the room). If you hate the baseboards and have an extra few thousand dollars to throw away, you could look at under floor, wall or ceiling radiant heating and/or ceramic wall heaters (used to be called "glass heat"). All of them work on the radiant heating principal and are supposed to warm objects rather than (actually, more than) the air, making it possible to set lower temps and enjoy similar comfort, thus saving energy/money. I don't have any experience to know if any of the claims are true, but I'm skeptical. My candid response would be don't fix what aint broke.

Doug M.
Old 02-09-04, 10:02 AM
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Like has been said.You can control anything By low voltage with some relays a transformer and a tstat, or what ever.

Radiant heat in the ceiling electric. No good have taken many out.But put electric furnace or heat pump for heat back in

Have also tried radiant gas over head it didnt work to good .

My .02 cents

Old 02-09-04, 04:30 PM
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I did a little more digging and did find 3 relays below the breaker box that are the same brand as the baseboard heaters (Singer). They are all single pole single throw relays that appear to all be wired into the 24 volt control line from the thermostat. The other side of the relays are directly tied into the line side of the breakers. The schematic on the outside of the relays shows 240V on one side with 24 volt controls. It looks like the 24 volt thermostat controls the switching of the line voltage side of the relay and there is one relay per breaker.

So it now looks like I understand the circuitry. It looks like any 24 Volt programmable thermostat would do the job in controlling the input to these relays?

Thanks for all the great help! Any other comments are appreciated!
Old 02-09-04, 04:46 PM
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Id call the power company and get a head man there . Ask him why they dont have low voltage tstat for this . Il bet they do and you can get one. ED
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