Immergas Short Cycling on Low DHW Demand

Water heater frequently cycles on and off rapidly when there is a small hot water demand.

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

Minimum burner power too high for demand, Scaled heat exchanger causing rapid temperature rise, Incorrect flow sensor calibration, Very low flow at tap

How to Fix / Troubleshooting

Safety: Turn off power and gas before internal work.

Increase flow: Open the hot tap more fully to increase flow and reduce cycling.
Descale heat exchanger: Remove scale from the primary and DHW plate heat exchangers to improve heat transfer and reduce rapid overheating.
Service settings: Have a technician check minimum burner modulation and DHW parameters.

Note: Some cycling at very low flows is normal; persistent rapid cycling at normal flows indicates a fault.

Repair Difficulty

Medium 3/5

Required Part

Primary Heat Exchanger

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