Noritz Sensor Drift / Intermittent Thermistor Fault

Boiler display shows fluctuating temperatures and heating is unstable, but no error code is present.

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

Aging thermistors, Loose sensor connections, Electrical interference on sensor wiring

Safety: Turn OFF power before handling sensor wiring.

1. Inspect sensor wiring: Check inlet, outlet, and heat exchanger thermistor leads for loose plugs or damaged insulation.
2. Secure cables: Route sensor wires away from high-voltage lines to reduce electrical noise.
3. Monitor behavior: If fluctuations persist, a technician should measure sensor resistance and replace any out-of-tolerance thermistors.

Medium 3/5

Outlet Thermistor

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