Honeywell Thermostat Says Heat On But No Heat [Solved]

There could be any number of reasons your Honeywell thermostat says heat on but no heat is coming into your home. These include:

  • Thermostat settings
  • Battery issues
  • Furnace ignition problems
  • Low refrigerant charge
  • Defective furnace blower
  • Blocked outdoor
  • Blocked registers

We are right in the middle of winter; some temperatures can be too low for you and your family to bear without a heater. That is why, you always need to have your heating system working without fail.

Also read: Honeywell Thermostat Heat Not Working [7 Fixes]

Honeywell Thermostat Says Heat on But No Heat Coming [5 Easy solutions]

A thermostat and a furnace work hand in hand to keep your home warm. But when any of the two has issues, it could affect how the other one works. So now let’s look at the reasons for your heat not turning on despite the thermostat saying, ‘heat on.’

1. Delay Mode Can Cause Honeywell Thermostat Flashing Heat on Message

Is the message on your thermostat flashing “heat on” message? If so, your thermostat could be in delay mode. In delay mode, your thermostat protects your compressor and your entire HVAC system from damage.

This usually happens when your system is recovering from a power outage but it should not take longer than 5 minutes. If the flashing message doesn’t stop after 5 minutes, there could be another issue with your heating system.

These are some of the icons or messages that indicate that your Honeywell thermostat is in heat mode.

  • “Heat”
  • “Heat On”
  • Fire Icon
  • Sun Icon

If any of the above icons or message display on your thermostat without flashing, your heat should work. If not, move to the next step of troubleshooting.

2. Tripped Circuit Breaker

If you are using a thermostat that is battery powered, it’s possible that it can be saying heat on when your furnace is off. A tripped circuit breaker is the reason your furnace could be off. Besides tripped breakers, a furnace power switch that is flipped could also cut power to your furnace.

Solution: Check for any circuit breakers that are tripped and flip them back on where necessary. But take note that if breakers continue tripping, there could be another issue with your furnace, and you need to call a licensed HVA professional to come and take a look at it.

You’ll also. need to check the furnace power switch if it is on.  You can find a power switch near the furnace. Switch it on if necessary

Another thing that will turn off your furnace is an open furnace cover. If you were just from changing air filters or you were checking out something in your furnace unit, you might have not closed it fully. Close it fully.

3. Thermostat Wiring

Thermostat on heat
Thermostat set to heat

Assuming there is nothing wrong with the power issues, lets to go to the next step of troubleshooting.  If heat is not working but you can feel air coming out of vents, the problem could be an incomplete or bad thermostat wiring.

At this point, you need to check the wiring of your thermostat.

4. Battery Issues

Does your thermostat rely on batteries? When batteries are low or when they are about do die, they can cause issues with your thermostat.

A dying battery can stop your HVAC system from responding to thermostat setting changes. So, when you set your thermostat to heat, your HVAC system might not respond to that. Other issues caused by a dying battery if failure to turn on and off your heating system

Read also: Honeywell Thermostat Flashing “Cool On” [7 Easy Fixes]

5. Furnace Ignition Problems

If you use a furnace for heating and your Honeywell thermostat says heat on but no heat coming through, there could be problems with your furnace ignition. Some issues that prevent your furnace from igniting include

  • Closed gas valve
  • Dirty flame sensors
  • Pilot light not working
  • Furnace door not closed (this can be the cause if your thermostat uses batteries)

Solution:  When your furnace is not igniting, make sure that the gas valve is open. When the valve handle is in line with the pipe, then its open. Otherwise, if the valve handle is perpendicular to the pipe, then it’s closed.

To fix this heating problem, you should also clean your dirty flame sensors. Flame sensors are sooty and dirty will prevent the furnace burners from turning. They will cause your furnace to shut down shortly after turning on.

The pilot light ignites the burners. If its not working, your furnace won’t ignite. Call HVAC repair services to come and have a look.

Another common thing that prevents your furnace from igniting is an open door. Close the furnace door, and you’ll be surprised by how quickly this issue will get resolved.

Also read also: Honeywell Thermostat Blank Screen [7 Fixes]

6. Low Refrigerant Charge

Your heat pump does not produce heat. Instead, it heats your home by using refrigerant. The refrigerant is responsible for bringing heat into your home. It absorbs heat from the outdoor air and takes it right into your home.  If the refrigerant is leaking out of your HVAC system, you will end up with little or no refrigerant in your heat pump system.

If your heat pump doesn’t have refrigerant, it will not cool or heat your home when you need it.

Solution: When you have low refrigerant in your heat pump system, you will need to call a licensed HVAC technician to come and verify the refrigerant charge and recharge the system when necessary.

7. Defective Furnace Blower

The furnace blower (in the furnace) and a blower fan (In the heat pump,) are both important in heating and cooling your home. The furnace blower draws the air into the furnace to be heated and forces it into the air ducts for distribution into your home. When the furnace blower is defective, no hot air will come into your home from the furnace.

Common issues with the furnace blower include

  • Dead blower capacitor
  • Broken motor belt (in older furnaces)

You’ll need to call HVAC professionals for these issues to be fixed.

8. Blocked Registers

Sometimes when you don’t have heat coming into your home, the problem could not be with your furnace or heat pump but with closed registers and vents

Make sure vents and registers are not closed or blocked by objects such as curtains or furniture. Remove objects blocking them and check if the hot air has started coming through.

Final Thought

There could be a few reasons your Honeywell thermostat says heat on, but no heat is coming through. But when you experience these issues try out these tips before calling HVAC professionals. If none of our tips help, then perhaps calling in professional service will help.


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