45
Noritz External Recirculation Pump / Control Fault

Error code 45 appears; unit may not operate in recirculation mode.

Advertisements

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.

Advertisements

Possible Causes

Incorrect wiring of external pump to Noritz control, Failed external recirculation pump, Faulty pump relay output on PCB, Misconfigured recirculation settings

How to Fix / Troubleshooting

Safety first: Turn OFF power to both the heater and external pump. Close water valves if working on plumbing.

Steps to check and correct:

  • Verify wiring: Check that the external recirculation pump is wired to the correct Noritz terminals as per the installation manual. Correct any miswiring.
  • Check pump power: Confirm the pump has proper voltage when recirculation is called for. If no power is present, the PCB relay may be faulty.
  • Test pump directly: Temporarily power the pump from a known-good source (using safe electrical practices) to verify it runs. Replace the pump if it does not operate.
  • Review recirculation settings: On models with controllers, ensure recirculation mode and timers are configured correctly.
  • Professional diagnosis: If wiring and pump are good, the Noritz PCB may need replacement by a technician.
Advertisements

Repair Difficulty

Hard 4/5

Required Part

External Recirculation Pump
Check Price on Amazon

We may earn a commission from links on this page.

Advertisements