Hiya folks -
I have an old gas furnace, original to my 30-year-old house. It has a
standing pilot and is in good shape, and I have a digital programmable
thermostat (make unknown). The problem is that the thing won't come
on reliably, and there doesn't seem to be any pattern to it.
I have the thermostat programmed to raise the temperature to 70
degrees at 5:30 every morning. The stat flashes the word "Heat" on
its display when it's trying. Some mornings it works, and others it
doesn't. Even when the furnace doesn't come on, the thermostat is
flashing "Heat" as if it's working. The pilot light is always lit.
I've found that if I take the thermostat off the wall to expose the
two wires coming up from the furnace and I short across those two
wires with another wire and hold it there for a bit, then usually the
furnace will come on after a while. If then I plug the business part
of the thermostat back in, it will work properly. Then next time it's
supposed to come on, maybe it will and maybe it won't.
How is this supposed to work? What should the voltage be across the
two wires that come up from the furnace? Does the thermostat send
voltage down to the furnace when it's signalling it to come on, or
does it just make a connection between these two wires for the
duration of the heat program? If I measure the voltage across these
two wires, I get something very low, like 0.2 volts DC. Have I got a
faulty thermostat or is there something wrong down at the furnace?
Thanks a million -
You should have 24 volts ac.
(measure again with the meter in the ac mode)
If the voltage is still low, check the wiring for a bad connection.
(this can cause an intermittent problem)
No problem, just send a half a million, please!!! :-)
(want the address to send it??)
Better yet, I'll pick it up personally. :-)
(wouldn't want it to get lost in the mail) :-)
( kjpro @ starband . net ) remove spaces to e-mail
Want it done yesterday? Or done right today, to save money tomorrow!!
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