On Jan 1, 12:24*am, Ignoramus21023 ignoramus21...@NOSPAM.
21023.invalid wrote:
On 2012-01-01, Ed Pawlowski wrote:





On Sat, 31 Dec 2011 21:10:23 -0600, Ignoramus21023
wrote:

During the day, I want the temp to be 47 degrees, and at night, I
would be happy with 38 degrees or so.

Do programmable thermostats need a separate power supply, or can they
run themselves from just a pair of 24v wires that they open and close?

No wiring needed. *Programmable stat use batteries to power the clock
but the same wires are all that is needed to make them work.

You will find that they have a minimum setting of 40 degrees. *Yeah,
33 would save fuel, but 40 give a safety factor in case the heater
break down.

I've had good experience with Honeywell and White-Rodgers. *We have a
couple dozen or so in our building.

And those, are two wire programmable thermostats with a battery? Right?- Hide quoted text -

- Show quoted text -

Take a look at any of the programmable thermostats at HD or
online. Everyone that I've seen runs off batteries and will work
with a simple two wire connection. Some will
also use 24V, if available. Some also have an internal failsafe
switch that will close at around 40 or so in case the batteries
are dead. I'd check the min temp before you buy one. The
ones I've had for sure will not go down into the 30's. Think
45 might be the lower limit.

And before going below 45, I'd consider where pipes that
could freeze are located. For example if
they are in outside walls, it's going to be substantially colder
there than where the thermostat is located. When I've set
back real low, like below 50, I make sure to leave open
the cabinet doors under sinks that are on outside walls
too so that it can get some more warm air in there.