How to Fix / Troubleshooting

Safety: Turn OFF power before opening the unit. Do not touch live components.

Noise reduction steps:

Remove the front cover and identify the source of the noise (listen carefully with the unit briefly powered if necessary, using extreme caution).
Check that the control board and any relays are securely mounted and that mounting screws are tight.
Inspect all high-current terminals for signs of arcing or looseness. Tighten connections to spec.
If a specific relay or triac is chattering or buzzing excessively, the control board may be failing and should be replaced.
Install water hammer arrestors on nearby plumbing if pipe banging is transmitting vibration to the heater.

Persistent loud electrical noises should be evaluated by a technician to rule out arcing or overheating.

Unit makes a loud clicking or buzzing noise when hot water is used.

Possible Causes