Zehnder malfunction
Zehnder ventilation unit hums
Is your Zehnder ventilation unit, HRV unit or ventilation motor humming? A humming noise can be caused by worn bearings, a heavy-running motor, imbalance, contamination or resonance in the casing or ducts.
- Constant hum
- Vibrations or resonance
- Motor overhaul often possible
What do you notice?
- The ventilation unit or HRV unit produces a low hum.
- The humming is constant or gets worse at a higher setting.
- You hear vibrations through the wall, floor, ceiling or duct.
- The motor is still running but sounds heavier than normal.
Possible causes
- Worn bearings or rotating parts.
- Imbalance in the motor or fan impeller.
- Contamination or age of the ventilation motor.
- Resonance due to mounting, housing or ductwork.
What can you safely check yourself?
Check whether the humming comes from the motor itself or mainly resonates through the housing or ducts. Also pay attention to whether the sound changes at a different ventilation setting. Always disconnect the unit from power before opening or inspecting it.
Not sure where the humming comes from?
Use our troubleshooting guide to determine step-by-step which cause best fits your Zehnder ventilation system.
Start the troubleshooterWhen is overhaul possible?
If the humming is caused by wear and tear on the motor, bearings or rotating parts, overhaul can often be a good solution. This can make your existing Zehnder system quieter and more reliable again.
Choose the right solution
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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