TOTALINE Model #P474-1035 Programmable 5-2 Day Digital Thermostat

My thermostat has 3 kinds of hold: temporary, permanent, and "vacation". IIRC, the last one can be set for a number of days before it reverts.

would go out if the room temperature would reach 82°.

low, at 76,in which case the light stays on, but the circuit to the furnace is open, ie no call for heat. I'd say time for a new thermostat.

He needs one of these

at 82° but the furnace stops when the room temperature reaches 76? ?.

DOWN buttons. According to the owner's manual, this "Bi-color LED" light " will only energize if the thermostat is system powered". This light stays on (red) even after the furnace stops when the room temperature reaches 76 °. My guess is that the light

emps, ie it's on when the furnace is on, out when it shuts off, then I'd sa y your guess is correct. This could be what I said earlier, it may have a fail-safe mechanical temp switch that opens if the temp is abnormally high. It may be defective, opening too

ace is open, ie no call for heat. I'd say time for a new thermostat.

ROFL that would work.

You should be able to get to 82 this time of year as it is not all that cold yet. I'd take it out and get one of the old style round Honeywell and set it where you want it.

Finally, an indication of the problem.

Where does she live?

What is the outside temperature?

Good questions.

Not only that, the weekends are the same as weekdays except 10 instead of 9:30.

Maybe she sleeps late on weekends?

Maybe those are the times he stokes the coal furnace?

Also, the model of the thermostat should have been in the body of the post, where I would have seen it, instead of hiding in the subject line.

Burford T J: Ask I said previously "My Mother is 95 years old. If the tem perature is below 82°, she's too cold".

I have a Totaline Model P474-1035 Programmable Thermostat.

This is the link to the owner's manual:

page 6 describes how to operate the thermostat MANUALLY:

- the Program Switch is at the "OFF" position. - the Fan Switch is at the "AUTO" position. - to set the desired room temperature, use the UP & DOWN buttons. - to turn the furnace on, move the Mode Switch to "Heat" - to turn the A/C on, move the Mode Switch to "Cool".

page 17 describes how to adjust the:

- "deadband". What is "deadband"? How many degrees should I set it to? - cycles per hour. There are 7 values: 2 to 6 degrees; 'd'; and 'dl'. What value should it set it to?

I'm only familiar with deadband as applied to thermostats that automatically switch from heat to cool on their own. In that case you don't want the heat and cool fighting with each other, ie if you want it 75F, you don't want the heat bringing it up to 76, then the cooling taking it down to 75 or 74 over and over. So deadband is where both are off. With a deadband of 4, the temp would have to go below 73 for it to go into heat mode or above 77 for it to go into cooling mode. Your thermostat doesn't say anything about auto changeover, so IDK what deadband is in that context. It may be the range around the desired temp where it fluctuates, ie with a deadband of 4 and a set temp of 75, the heat will come on at 71, go off at 79, but that seems nuts.

Since you're having problems, I'd set the deadband to 1, the lowest. The cycles per hour are number of cycles, not degrees. It's how many times you want the furnace to typically run to maintain the temp. For example if it's 30F outside, it could run once an hour to keep it close to 75F or it could run 5 times. The latter will keep fluctuations smaller, the former is a little more energy efficient. I'd set it to 3.

It's possible that deadband setting is your problem. What was it set to? If it's high, eg 6, that might be why it's cutting off at 76 instead of 82.

I've set the "deadband" to 1, the "cycles per hour" to 3 and reduced the "desired temperature" from 82 to 78. The furnace then raised the room temperature to 77 and the furnace then kicked off.

Now, I raised the "desired temperature" to 82 degrees. I'll see what the room temperature reaches.

The "desired temperature" is 82 degrees The room temperature is only 75 degrees. The red light between the thermostat's UP and DOWN arrows is on. The furnace is NOT running.

Two hours later:

The room temperature is 81 degrees. The red light between the thermostat's UP and DOWN arrows is on. The furnace is NOT running.

Turn the furnace power off. Remove the thermostat and just connect the two wires that call for heat, yo u can identify them from the thermostat terminals. Usually they are the re d and white. The furnace should run continuously. Let it go for 30 mins or more to verify that you don't have a problem with the furnace where it's s hutting off on its own.

If that works, you need a new thermostat.

If the voltage between the R and W terminals in the thermostat is less than than 20-30V, would that indicate a problem with the thermostat or the furnace?

Are you measuring it with the thermostat disconnected? If so, then you should have ~24V there and if it's substantially lower, then it looks like a problem with the transformer, most likely. Could be a partial short too. If the thermostat is connected and calling for heat, the voltage should be zero. If it's not, then it's a problem with the thermostat.

If the thermostat is connected but not activated, it should also be

You could measure the voltage at the transformer too, just be sure if you're on the primary side or the secondary. 24V won't kill you, 120V could.

OMG! Cleaning the "flame sense rod" resolved my furnace problem. Now my furnace is working (i.e., the room temp is now above freezing!).

I was fearing having to call a HVAC technician who would try to sell me a new furnace for a gazillion bucks.