Pure Enrichment Heating Pad Flashing F – My thermostat is blinking heat on. It is normal for a lot of furnaces to have an indicator light to say the heat is on, so you know when it isn’t. I’d know when the heat isn’t on because everyone in my household would literally give me a cold shoulder. It is normal for some brands like Braeburn to have a flashing word heat when heating. I’ve never even heard of Braeburn, much less use their HVAC equipment. Some furnaces have a red blinking light on the thermostat when the thermostat’s batteries are low. My thermostat should be wired for power. A lot of furnaces have a blinking light they used to give error messages.
The light that is steady when the furnace is on normally could be blinking because something is wrong. Then I need to find the user manual to figure out what the error means. Then again, some furnaces have a flashing heart beat pattern or one second on and one second off pattern as their normal indication that everything is fine. This blinking is not the norm for my furnace. It could be blinking heat on while calling for heat, which causes the control board to do checks for the pressure as it turns on the inducer motor. At that point, the inducer should come on, make sure all the other switches are off, then turn on the heating element or gas and ignition.
The heat light could be blinking because the thermostat calls for heat but the furnace’s pressure switches are stuck in the wrong position, so the furnace never turns on. That would explain a blinking error light too. It could also have the inducer motor turn on but the unit fails to ignite or heating element to come on. I’d also see a flashing error if the furnace tries to turn on but fails, whether because the gas doesn’t ignite or the blowers don’t start up in time. You should at least hear that when it tries to start until it locks out. Could the heat on light flashing mean it is locked out? That depends on the model of furnace, but usually the error lights are something other than the normal operating green light.
If you have a gas furnace, the flame sensor would flicker or flash if it can’t see a strong flame. That latter case would be a reason for it to shut down and lock out too. You can try to fix it by power cycling the furnace. That’s the fancy work for hitting the reset button or turning it off at the breaker and back on. At least then you’ll have tried the thing you’d be embarrassed to see the repair guy try before you call for service.