How to Fix / Troubleshooting

Safety: Turn off power before accessing internal components.

Check flow rate: Ensure that the hot water draw is above the heater's minimum flow requirement. Very low flow can cause cycling.
Verify setpoints: Confirm that temperature and power settings are appropriate and not causing rapid overshoot.
Inspect sensors: Test flow and temperature sensors for stable readings. Replace any that show intermittent behavior.
Hydraulic balancing: In systems with storage tanks, ensure proper tank sensor placement and control configuration to avoid rapid cycling.
Consult design: If the heater is significantly oversized, consider adding a buffer tank or adjusting control strategies.

Water heater frequently cycles on and off with short run times, even with steady hot water demand.

Possible Causes