Ferroli Noisy Relay / Coil Vibration

Thermostat makes a constant buzzing or humming noise from the receiver when calling for heat.

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.

Possible Causes

Relay coil operating at marginal voltage, Worn relay contacts causing chatter, Loose mounting of receiver on wall amplifying vibration, Overloaded relay switching inductive loads

How to Fix / Troubleshooting

Safety first: Receiver contains mains voltage. Isolate power before opening.

Confirm source of noise:
- Place your ear near the receiver to verify the buzzing originates there, not from the boiler.
Check mounting:
- Tighten receiver mounting screws to reduce vibration.
Reduce load:
- Ensure the relay is only switching the boiler control circuit, not pumps or valves directly.
Replace receiver if buzzing persists:
- The relay may be failing; install a new Ferroli smart thermostat receiver.

Repair Difficulty

Medium 3/5

Required Part

Ferroli Smart Thermostat Receiver Relay Board

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