Giant Thermostat / Control Non‑Responsiveness

Water heater does not respond to thermostat adjustments, temperature remains constant

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

Stripped thermostat knob, Faulty temperature sensor, Control firmware locked, Broken linkage on mechanical thermostat

Safety first: Turn off power or gas before removing thermostat covers.

Verify knob function: On mechanical Giant thermostats, ensure the knob actually turns the internal adjustment and is not cracked or slipping.
Check sensor: On digital models, test the tank sensor resistance and replace if out of spec.
Reset control: Power cycle the unit to clear any temporary firmware lock.
Replace thermostat/control: If adjustments have no effect, replace the Giant thermostat or electronic control board.

Medium 3/5

Giant Gas Thermostat/Gas Control

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