How can I tell if the thermostat that controls the natural gas furnace downstairs is low voltage.?
Friday, September 3rd, 2010 at
11:00 am
How can I tell if the thermostat upstairs that controls the natural gas furnace downstairs is low voltage and not dangerous? Any non-serious response will be reported to Yahoo.
Thank you.
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Very, very few are controlled by line voltage ….in fact I have never run across one in a domestic setting.
The wire size for low voltage will be about the size of a tooth on a comb, generally with a group of other wires from 4-6 wires Red, Yellow, orange, gray, blue, white, brown …..
The size of the wire is a good indication, but if you take the cover off the the thermostat it should tell what voltage it’s operating at. If this is a hot air furnace, then for sure it will be low voltage.
Vinny
I have not seen a 110 volt thermostat in 20 years. About the only place they would be found is on an electric space heater. All modern thermostats are run with low voltage created by a transformer in the furnace itself.
Don’t get your shorts in a knot here Brownie, I doubt that Yahoo concerns themselves with whether or not someone answers a question in a serious manner or not. The easiest way to tell if anything is a low voltage appliance is to look at the wires. Low voltage items are powered by very small wires, that are usually rated to carry 12 – 24 volts, which is what your thermostat will be on. Line voltage thermostats are used on electric wall heaters, seldom on gas units. If you have a small brown wire bundle going to the basement you can be sure your thermostat is low voltage.
Usually all thermostats for gas furnaces are 24 volts ac.
Line voltage thermostats are usually clearly marked behind the cover.
Low voltage stats will have small wires attached to the terminals.
If it is just a simple two wire system you could put a volt meter across the two terminals with the thermostat turned all the way down you will read the voltage.