Furnace thermostat error m15

Our technicians have found the cause of our furnace’s M15 error and have repaired it.

One of these parts may be failing or not performing at an expected level:

The Outdoor Sensor

Error 13 Contactors

Ground Fault Interrupter Switch

Parking Relay

Pot Load Relay

—

The furnace panel seems to always be running because the temperature sensor is not sending a signal, two points of lint prevent the stripe from reaching the sensor.

The problem is likely to be that the ceramic-type sensor, must touch a ceramic strip which is inside the slot and when both are clean and in place, it sends electricity to tell the furnace that it is at the desired temperature.

Sometimes there will be a 4-digit code or 2nd F1 or W1 when this happens. The error message M15 means that there has been an issue with pyroelectric heat fuses at 2 positions near the heat exchanger

—

We reveal some common furnace thermostat errors, what to do if you experience one, as well as an explanation for how these errors may happen at all.

­­­­Furnace thermostats can be likened to the brains of your HVAC system. They allow your furnace and other components to work together effectively to maintain a comfortable environment.

Luckily, you don’t have to learn furnaces inside and out to detect a problem with a thermostat, like an error code reading M15. ­­