Display shows A12, unit may run at reduced power or shut down intermittently.

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

Faulty modulating gas valve, Damaged modulation coil wiring, PCB modulation circuit failure, Incorrect gas valve calibration

Safety: Only qualified personnel should adjust or replace gas valves.

1. Check wiring: Inspect the low-voltage modulation connector on the gas valve and the corresponding PCB plug. Reseat and secure them.
2. Observe operation: During hot water demand, the flame should modulate smoothly. If it surges or cuts out, note the behavior for the technician.
3. Technician tasks: A professional will test modulation signals, verify gas pressures at minimum and maximum rate, and replace the gas valve or PCB if modulation cannot be controlled correctly.

Professional Required 5/5

Modulating Gas Valve

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