We recently had a call where a client’s A/C wasn’t working. They had tried to change the thermostat and wired it incorrectly. As we checked out the system, we found that in the process of miswiring the thermostat they actually burned out the control board on the blower motor.













This is a control board from the end of an ECM motor in a Frigidaire gas furnace.

As systems increase in efficiency they also increase in sophistication. There are many control boards in newer equipment that are very sensitive to voltage spikes. In this case the blower motor was asked to run at two speeds at once. This caused an over current issue causing this part to fail “letting the smoke out”.

Long story short, this caused a very expensive repair. These ECM, Electronically Commutated Motors, are very reliable BUT very expensive motors. They are placed in systems to increase efficiency and comfort in HVAC equipment.

Our advice to anyone that wants to DIY. Know your limits. It may seem easy but don’t second-guess. If you don’t know, find out or call a qualified technician. The service call to install the thermostat would have been substantially less than the final repair cost. Not to mention, they were without A/C several days.

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Dynamic Plumbing, Heating & A/C is a family owned and operated business serving The Shenandoah Valley.

We are a Family Owned and Operated business servicing The Shenandoah Valley. Dynamic Plumbing, Heating & A/C provides service, repair and replacement for all aspects of plumbing, heating and air conditioning for residential and commercial clients.