Nibe
Circulation Pump Noise / Partial Seizure
Water heater emits a humming or buzzing noise from the circulation pump area.
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Air trapped in pump, worn pump bearings, pump running against closed valve, cavitation due to low system pressure
How to Fix / Troubleshooting
Safety first: Turn off power before opening pump vents. Hot water may escape when venting.
- Step 1 – Vent the pump:
- Open the pump’s vent screw slowly until air escapes and water flows steadily, then retighten.
- Step 2 – Check valves and pressure:
- Ensure isolation valves around the pump are fully open.
- Verify system pressure is within the recommended range.
- Step 3 – Free the rotor:
- With power off, remove the pump plug and gently turn the shaft to ensure it spins freely.
- Step 4 – Monitor noise:
- Restore power and listen; if the noise persists or worsens, the pump may need replacement.
Do not ignore grinding or screeching noises; they indicate imminent pump failure.
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Repair Difficulty
Medium
3/5
Required Part
Circulation Pump
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