Question About A Digital Thermostat

Take it outside or put it in the fridge for a while and see what it reads.

Already did that, no change. I would think it's supposed to work like a regular digital thermometer that you put batteries in. Maybe it's fried right out of the box?

i think the key here is "someone gave me".

Just guessing here... is 72° the 'target', or desired temperature, as opposed to the current actual ambient room temperature?

Erik

More... looks like a pdf of the instruction manual is available here:

Yeah, my father that just passed away and bought it brand new......asshole!

It says in the manual that I have, that the room temp can be set to -/

• 3 degrees. But, that doesn't answer my question. Does it need to be wired in order for it to show the actual room temp? Like I said, with the batteries only, it is stuck on 72 degrees. I don't want to waste my time installing it if the room temp is supposed to be displayed by the batteries only.

Perhaps that number is on the sheet of clear vinyl that protects the screen from being scratched.

My 30 y.o. semi-digitial set-back thermostat just uses the battery to power the clock. Everything else comes from the furnace.

Oh man-- I did that once. I don't even remember what the gadget was--- I remember a lot of cussing, head scratching-- and then a lot more cussing.

Jim

All the digital battery operated ones I've ever seen only need the batteries to run all the display functions. Can't imagine why it would need to be connected. The rest of the process is just closing one of several relays to connect the wires to the furnace for heat, cool, fan, etc.

Even they are set in the off position, ie no heat, cool, then all the ones I've seen display the room temp.

I guess it's defective. Thanks.

Don't know FOR SURE on that thermostat, but for MANY the battery just holds the settings and runs the LCD display, while the actual "thermostat" runs off the controll transformer.

Well, I would hook it up and see, but the wires coming out of the wall are VERY short. Changing out my thermostat is a real PITA.

The 72 is the room temp. When I put batteries in it I can adjust the desired temp. The only thing I can do to get it off of 72 degrees is go into setup mode and I can change the room temp to +/- 3 degrees. I see nothing in the manual about the room temp reading other than that.

I thought you intended to do it regardless.

Solder 2 or 3 inches of anything, 4-conductor phone line?, onto what's there, and slide heat-shring tubbing over each splice, warm with a kitchen match until it shrinks. IF it's too long now, push part back into the wall.

I have a roll of thermostat wire that a AC guy gave to me, but if this thing doesn't work, I don't wanna waste all of that time. I have a manual Honeywell thermostat that works perfectly fine. Just would have liked a digital since it was free.

Do you have any way to feed it 24 V AC? To terminals R and C? You don't need to hook it up to the furnace to check it, just feed it some jolts. Maybe a small appliance power supply or charger.

Good idea, or the 24 volts at the furnace itself, or the 24 volts at the thermostat.

That's why I always recommend people make or buy a bag of wires with alligator clips on both ends. They used to come in lightweight and heavyweight, but now Radio Shack has only heavy weight, 6 inches, 10 for 4 dollars or so. Takes 2 seconds to clip one end to the thermostat wire and the other to the thermostat screw, times 2 = 4 seconds.

I once used a 30-inch long wire with alligator clips at each end to bypass some problem in my car's ignition harness. Found the wire in the harness just before it went into the firewall, and ran the other end of the jumper wire to the coil. I meant to find the break and fix it but that looked like it would be hard, so I just drove that way for

I'm betting 99.9% chance the thermostat is bad. I've never seen one that powers up on batteries, that then:

displays room temp, displays set temp which he says he can change yet, the room temp will not change from 72.

unless he has a sticker with 72 on it, I don't see how it can be anything other than bad. Still, I would put 24V on it just for the hell of it.