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Joe Joe is offline
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Default Digital Heat Thermostat: If Batteries Run-Down, What happens ?

I am not sure of your concern but I went and read the manual to this
thermostat and it is entirely digital as it has no manual switch. It does
not say what it defaults to in case of no power battery or otherwise. My
guess would be off but that is just my guess. In any case if you do not
think you can remember to put new batteries in it or may be away from it for
extended periods of time this may not be the thermostat for you.
You may be better of with one like I have. I have a Robertshaw 9520. It
is a digital thermostat that requires no batteries. I has a manual switch
though for Heat, Cool and Off. With mine If the switch is in the Heat
position and the power fails it comes back on with the heat set at 60, if
the switch is in the Cool position it comes back on with the air set at 80,
if the switch is in the off position it simply stays off.

Joe

"Robert11" wrote in message
. ..
Hello:

Have a gas, forced hot water heating system.
Was about to order a Honeywell thermostat over the web, but had the
following concern which
just dawned on me.

Am interested in their digital model RTH 5100 which is non-programmable.

It says on their ad sheet that it maintains the set-point if there is a
power outage.
O.K., that's great.

But even if there is house power--

These units require a battery or two.

What happens if the battery runs down while you are away ?
I know, use new, fresh, batteries, etc. But-

Will the furnace shut off if battery runs down ?

Or, is the battery only for the display, and the circuitry still works ?
If so, how, as there's no current when
the circuit is calling for no heat thru the 2 wires.

e.g., with no thermostat battery voltage, does the curcuitry default to a
circuit closed condition, which would
keep the furnace active, or... ?

A bit worried about this.

Thanks,
Bob