So if I send you a 24volt 40va transformer,,,,, you'll plug it in with
one hand holding the frame and your thumb of that same hand across the 24V
**CAUTION** No one should try this as this as it only takes .001amps to
stop the heart***(yes, I described the act above with dumb-ass safety
protocol in mind.)
This is one of my pet peeves on this NG. Everyone knows that they can
call a professional. so why do people even bother to post such a
thing. The whole point of this NG is to find solutions for doing our
own repairs. Yes, on occasion I have read someone doing something
that does sound dangerous and have myself suggested they get a pro.
But messing with a thermostat is definately not going to blow anything
up. And for the record, calling a furnace pro will cost much more
than a FEW bucks. They are not cheap. Homeowners should be able to do
minor repairs, unless they are millionnaires.
For the OP.
1. make sure the breaker is turned ON for the furnace
2. Make sure the switch on, next to, or near the furnace is turned ON
3. be sure the thermostat is set to HEATING, not to AC.
4. turn the thermostat as high as it will go and see if the furnace
lights. (turn it back down after).
5. If you have a programmable thermostat, set it to MANUAL or (on
mine), it;s called HOLD.
6. As a last resort, remove the thermostat and either try a different
one, or temporarily short the wires together if there are only 2 of
7. If you have any electrical knowledge, there is a transformer in the
furnace that supplies 24 volts. A test meter can be helpful to see if
there is voltage.
What type of thermostat? If it is a programmable one with a battery, it may
be as simple as putting in a new battery. It may have just enough power for
the display, but not enough to trip the contacts for heat. BTDT.
On mine, I have the feeling that the battery is only there to keep it
from forgetting things if I turn off the AC power to the furnace/AC.
I have only changed the battery once in 24 years, and I think
everything works fine as look as the power is on to the furnace.
Could that be the case, with my thermostat at least?
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