How to Diagnose a Noisy Heating Pump (UK)
Grinding, whining or humming pump? Root causes: air, seized bearing, cavitation, wrong speed setting.
GrundfosWilo
Cause by sound
- Grinding — bearing worn, replace pump.
- Humming without flow — seized impeller, free with screwdriver slot or replace.
- High-pitched whine — cavitation from air, bleed the system.
- Chatter under DHW demand — F&E tank overflow syphoning.
Frequently asked questions
- Can I lubricate a pump?
- No — modern wet-rotor pumps are self-lubricating from the system water. Noise = replace.
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