Why does heat come on when thermostat is cool?

The thermostat’s connection to the furnace and AC unit may become disconnected. Or the wiring from the thermostat to the units could short out. In other words, your thermostat may be in “cool” mode, but their furnace and AC unit have no way of knowing that. This can trigger the heater to turn on.

Why Does My Honeywell thermostat say heat on?





Honeywell Thermostat Troubleshooting

Check the thermostat is set to heat, and see if the “Heat On” button is blinking. This indicates a safety timer has been tripped to protect your thermostat’s compressor. Once this stops blinking, your thermostat should be able to maintain its heat setting again.

Why is my Honeywell thermostat on cool but not working?

Check The Thermostat Batteries

If the thermostat’s batteries are low, it will not be able to begin heating or cooling. To know if this is the problem, check your thermostat’s display for a ‘Battery Low’ indicator. Honeywell thermostats, on average, can function for about two months before they begin to display this.

Why is my Honeywell thermostat not heating?





A Honeywell thermostat won’t turn on the heat because of faulty sensors, improper installation, tripped circuit breakers, etc. The heat not turning on issue on your Honeywell thermostat may be fixed by resetting the Thermostat.

Why is my heat pump blowing hot air in cooling mode?

Your Heat Pump Has Lost Refrigerant

If there isn’t sufficient refrigerant moving across this system, it won’t be able to accomplish its task. You might have the right setting at the thermostat and the reversing valve could be just fine, but your heat pump will continue to blow out hot air while it’s in cool mode.

Why does my AC come on when I turn on my heater?

Your thermostat is set for “heat”, warm air is coming from your vents, and everything in your heating system seems to be working perfectly – except for the fact that your outdoor air conditioner unit is running. Why? The answer is simple: your outdoor unit is a heat pump.

Why does thermostat say heat on but no heat?



Seeing that your home thermostat says ‘heat on’ while in reality there is no heat is one of the most annoying things ever. What could possibly be wrong? The most common reasons for such a problem are a dirty filter, thermostat malfunction, pilot ignitor, wrong settings, or low battery issue.

Is there a reset button on a Honeywell thermostat?

Does Honeywell Thermostat Have A Reset Button? Honeywell digital thermostats don’t have specific reset buttons. It will take some maneuvering to revert to the original settings on most Honeywell thermostat models. Whether programmable, non-programmable, or Wi-Fi models, each has unique instructions.

Why is the heat symbol flashing on my thermostat?

When the word HEAT or COOL flashes it indicates that the thermostat is telling the heating or cooling system to run. If the heating or cooling system is not running then there most likely is a problem within the system. Contact a local heating / air conditioning contractor in your area to service your equipment.

Why is my heating not coming on?



Check your thermostats

If the thermostat is set too low, the heating will not come on until the room temperature is lower than the temperature you have set the thermostat to. Turn the thermostat up to its highest setting and see if this resolves the problem.

How do you know if your Honeywell thermostat is bad?

7 Ways to Tell Your Thermostat Is Broken

  1. Thermostat Has No Power. …
  2. AC or Furnace Won’t Turn On. …
  3. Heater or AC Won’t Turn Off. …
  4. Thermostat Doesn’t Match Room Temperature. …
  5. Thermostat Doesn’t Respond. …
  6. Short Cycling. …
  7. Thermostat Forgets Programmed Settings. …
  8. Thermostat Replacement Services.

Why does my AC work but not my heat?



A Faulty Thermostat

You need to start by checking if your thermostat is powered and working properly. Try turning on the thermostat and adjusting the temperature so that your HVAC is turned on. If it fails to come on, check the circuit breaker and ensure that the switch is functioning properly.

Why is my furnace running but not blowing hot air?

The Furnace Is Blowing Cold Air

First, check to make sure the thermostat is set correctly. You will want to make sure that the fan control is set to auto, and not ‘on’. If the thermostat appears set correctly, turn off your heater at the thermostat and check the filter. If the filter is dirty, replace it.