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Zehnder malfunction

Zehnder ventilation unit no longer spinning

Is your Zehnder ventilation unit, HRV unit, or ventilation motor not spinning at all? The cause could be the motor, bearings, capacitor, circuit board, or power supply. In many cases, repair or refurbishment is still possible.

Problem Motor no longer spinning
  • No air movement
  • Motor does not start
  • Refurbishment often possible
Start troubleshooting

What do you notice?

  • The ventilation unit no longer responds.
  • There is little to no air movement.
  • The motor tries to start but doesn't get going.
  • The unit remains completely silent or only hums.

Possible causes

  • Defective or seized motor.
  • Worn bearings or stiff-running rotating parts.
  • Problem with capacitor, circuit board, or power supply.
  • Wear due to prolonged use or contamination.

What can you safely check yourself?

First, check if the unit is receiving power and if the controls are working correctly. Listen if the motor remains completely silent, hums, or tries to start. Always disconnect the power to the ventilation unit before opening or inspecting it.

Not sure where the malfunction is?

Use our troubleshooting guide to determine, step by step, which cause best fits your Zehnder ventilation system.

Start troubleshooting

Can the motor still be repaired?

In many cases, yes. If the motor, bearings, or rotating parts are defective, refurbishment can often be an economical and sustainable solution. Only in cases of severe damage or non-repairable parts is complete replacement more advisable.

Choose the right solution

Zehnder motor refurbishment View repairs → More about Zehnder refurbishment View refurbishment page →

Read more about Zehnder

Also view our other information pages about Zehnder ventilation units, HRV units, parts, malfunctions, and refurbishment.

Zehnder ventilation units Main page of the Zehnder knowledge center Mechanical ventilation units ComfoFan Silent, ComfoFan S, Silent Limited, and CVM HRV units ComfoAir Q, E, Flex, Standard, ComfoAir 70, and ComfoSpot 50 Zehnder refurbishment Everything about motor refurbishment and repair Zehnder parts Motors, circuit boards, capacitors, and other parts Zehnder making noise Noise, vibrations, and wear Zehnder humming Constant hum or resonance Zehnder not spinning anymore Motor not starting or not responding Zehnder not extracting properly Low extraction or moisture problems Zehnder bearings worn Grinding or squealing motor due to wear

Is your problem or model not listed?

Use our troubleshooting guide or parts finder. We are happy to help you find the right solution.

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