Why does my intertherm heater blower come on in the summer and run for hours even with heat shut off?

If the unit is in the attic or even under the house and it gets very hot, the on signal for the air handler tells the fan to come on. I assume by "Heat shut OFF" you mean at the thermostat, not at the breaker box. You don't have AC?

The fan switch is set way too low and when the unit gets hot it will come on. You can set the "on" or cut-in temperature and the cut-out temperature. You will see it when you remove the front cover where you will see the switch attached to the heat exchanger. Remove the cover to the switch and you will see a dial with three sliders, two can be set, but the high-limit is set at the factory.

This unit is in the hallway- it is a heater only unit- the ac unit is in different part of house but I don't run it when I'm not there- is there a way to turn this off? It runs for 8+hours


The fan switch is set way too low and when the unit gets hot it will come on. You can set the "on" or cut-in temperature and the cut-out temperature. You will see it when you remove the front cover where you will see the switch attached to the heat exchanger. Remove the cover to the switch and you will see a dial with three sliders, two can be set, but the high-limit is set at the factory.

Can you translate this into "woman talk"? Lol

This unit is in the hallway- it is a heater only unit- the ac unit is in different part of house but I don't run it when I'm not there- is there a way to turn this off? It runs for 8+hours



Can you translate this into "woman talk"? Lol

Look on the side of the furnace to see if it has a on off switch. Or you could turn the breaker off.

There is a front cover on the furnace that you just lift and pull out to remove. Some heaters have an adjustable fan/limit switch and others do not. Most likely, the best way to stop this is to either unplug the furnace or turn off the breaker to it. More than likely you will need to replace the fan switch and if you have never done anything like that then it would be best to get someone who knows how, even though it's no more complicated than changing a light bulb to most. It just takes removing two screws and changing out two wires that plug onto it. Here is what it looks like: 47521