What is a fan coil motor?
Inside a fan coil there are one or two centrifugal (squirrel cage) fans and an electric motor that turns them. In classic fan coils, the motor is a single-phase AC motor with a capacitor and three separate speed settings. In newer-generation units, an electronically controlled EC motor is used; its speed is adjustable steplessly and it uses noticeably less electricity, especially at low speeds.
Fan coil motor fault symptoms
- Fan does not turn at all but the motor hums: usually a capacitor failure or a seized bearing
- Fan starts turning when spun by hand: the capacitor has weakened
- Only one speed works: a fault in the relevant winding or the thermostat output
- Metallic noise, friction, vibration: bearing wear or dirt buildup on the wheel
- Motor housing overheats, thermal protection trips: a winding problem or strain
- Burning smell: switch off the unit immediately and notify service
Fan coil motor fault or EC conversion
Tell us the unit brand and model, the symptom and the quantity; we will get back to you with a diagnosis and a quote.
Should the motor be replaced or repaired?
Replacing the capacitor and cleaning the fan wheel often solves the problem. For motors with a burnt winding or failed bearings, the motor must be replaced. What to watch for when replacing:
- Motor power, speed settings and shaft diameter must match the original
- The capacitor value must be chosen according to the motor label
- Rotation direction and mounting feet must be checked
- Current and speed must be measured after replacement
Switching from an AC motor to an EC motor
In hotels, hospitals and offices where many fan coils run long hours, converting to EC motors can reduce electricity consumption. For the conversion, the thermostat must be able to give a 0-10V signal; so the motor and thermostat should be planned together. How much saving there will be depends on operating hours and the existing motors; we assess it with measurements at the site survey. The price also depends on the motor type, quantity and whether the thermostat needs to be changed.
Frequently asked questions
Why does a fan coil motor not run?
The most common causes are a capacitor failure, a seized bearing, a burnt winding, a thermostat output failure or a power supply problem.
How can you tell a fan coil motor capacitor has failed?
If the motor hums but does not turn, or turns when spun by hand, the capacitor may have weakened. A definitive diagnosis is made by measurement.
What advantage does an EC motor offer?
Its speed is adjustable steplessly, it uses less electricity especially at low speeds, and it runs more quietly.
Can I replace the fan coil motor myself?
Because it requires an electrical connection and the selection of a compatible motor, we recommend that a competent technician do the job.