Live in a condo complex with a very strange thermostat. It has two high voltage wires (not sure if 110v or 220v) going to a fan control (low/med/high) then from there, it goes to the thermostat (for both heat/cool). Trouble is, it's old, the know is very hard to turn and I would like to replace with a modern 24V thermostat. Had an AC guy out that said it can be done, but that I would need an electrician to add voltage transformers...says he had a system done and cost near $300. Can I do this myself? How? Or can I just buy a new line voltage thermostat? Trouble is, the ones I have found only do heat or cool, not both.
2006-09-22 07:21:35 · 14 answers · asked by roobs 2 in Home & Garden ➔ Maintenance & Repairs
Go to a Plumbing Supply, Home Depot, Lowes, Sears or other home center and ask in the department that has preferably some experienced help. It would help to have as much information about the old thermostat as possible as there should be one that is a line voltage model as they are still made. They are not that expensive and it would be a lot more trouble to rewire for a new low voltage system. Since the condo already has a setup for the line voltage model, check around and get a licensed Electricians advice as that is more in his line of work and an Electrical Supply house carries a lot of different Thermostats too! Replacement "in kind" is cheaper, believe me.
2006-09-22 07:55:00 · answer #1 · answered by norman8012003 4 · 0⤊ 0⤋
Keep in mind that I am not a AC guy. I work in the electrical industry and have replaced a few low voltage thermostats. I am just using some funk logic here.
Here are your options. The first is to have the two line voltage thermostats next to each other on the wall. Not such a bad idea if you are afraid to dive into this mess.
The second option is a transformer. For starters, I would find out what your amperage draw is on that thermostat line (Probably not much at all). Then head down to your home store, like Home Depot and get a transformer for the required amperage at 120v transformed to 24v. You have wire the transformer in-line of the power cable, so (whether wire is in pipe or romex), you have to find a breaking poing (probably at the air handling unit / blower). The transformer will mount in a box or they have these "Box Transformers" that mount directly on the outside of an electrical box (also can buy at Home Depot). Then, use the wires that go to the thermostat to carry your 24volts. Just make sure to check the thermostat for the number of wires you need. Typically thermostats today have like 6 or 7 wire connections. If you just have a hot and neutral from power to the thermostat now, you won't have enough wire. You may want to consider fishing in a new multi-conductor wire back to the air hander / blower.
2006-09-22 07:36:37 · answer #2 · answered by Joey 4 · 0⤊ 0⤋
The new thermostat sounds like a typical 24V control thermostat, which is completely wrong for your system. Going by the picture you posted, you have line voltage control (120V). I'm surprised you haven't fried the new thermostat. Or maybe that picture isn't really what you have. It also shows a valve and aquastat, so you have a hydronic system (hot water) and not your typical furnace/compressor. What kind of building is this? If we ignore the voltage and the lower part of the picture, I think you should use the High fan setting to G instead of low. But the rest of your connections make sense. Since it isn't working for you, I again assume you have some other heating system. The schematic says to use 14 AWG wiring only. Are your thermostat wires that big, or the 18AWG typically used with 24V thermostats? If you really have 14AWG wires then I'm sure it is line voltage.
2016-03-22 15:48:03 · answer #3 · answered by Anonymous · 0⤊ 0⤋
This Site Might Help You.
RE:
How do I replace a line voltage thermostat with a 24-volt one?
Live in a condo complex with a very strange thermostat. It has two high voltage wires (not sure if 110v or 220v) going to a fan control (low/med/high) then from there, it goes to the thermostat (for both heat/cool). Trouble is, it's old, the know is very hard to turn and I would like to...
2015-08-06 06:26:42 · answer #4 · answered by Anonymous · 0⤊ 0⤋
High Voltage Thermostat
2016-10-07 05:36:58 · answer #5 · answered by ? 4 · 0⤊ 0⤋
120 Volt Thermostat
2016-12-14 12:47:09 · answer #6 · answered by levy 4 · 0⤊ 0⤋
24 volt thermostats work off the transformer that comes installed in the appliance being used. The fan motor is dependent on the 120 for the variable speed. You would have to rewire the motor to work with a new control board for the same operation. Probably not worth the expense or hassle. They do make 120 stats that control both heat and air. Search on line for one if you can't find it locally.
2006-09-22 13:52:36 · answer #7 · answered by audioworm31 3 · 0⤊ 0⤋
The line voltage guys are right. Conversion would be folly. A new appropriately matched thermostat will work best and may be more efficient. Do your research and see if there may be "set back" stats that will allow you to customize your heat/cool settings to fit your home/wake/sleep schedule.
2006-09-23 19:38:30 · answer #8 · answered by LoneWolf 3 · 0⤊ 0⤋
Buy and install a new line voltage thermostat. Use a tester prior to installation after removing the fuse or tripping the breaker.
Don't bother with the conversion.
2006-09-22 07:31:28 · answer #9 · answered by Krazykraut 3 · 0⤊ 0⤋
Norm & krazykrau are steering you straight.The bulk of the people who answered your query are F.O.S. You'll find it much simpler (and cheaper) to stick with your line-voltage control circuit. Bite the bullet and have an HVAC contractor do it. Good luck.
2006-09-22 14:22:04 · answer #10 · answered by Huero 5 · 0⤊ 0⤋