Noritz Error Code 45: Water Leak Detected

Severity
Warning
Type
digital display
Where to look
front panel
Estimated repair cost: $100 — $350 (parts + labor)
Warning: Your Noritz tankless water heater has detected a water leak. It's safe to use, but needs professional attention.

How to Fix Noritz Code 45

  1. Check all visible water supply pipes and connections for any signs of leaks or cracks.
  2. Inspect the water inlet and outlet valves for any signs of wear or damage.
  3. If you find a leak, turn off the water supply to that area and contact a professional immediately.

How to Reset Noritz Code 45

  1. Turn off the unit using the power button on the front panel.
  2. Turn off the gas supply valve.
  3. Turn off the circuit breaker supplying power to the unit. Wait 30 seconds.
  4. Restore power at the breaker, then open the gas valve.
  5. Turn the unit back on. If the error returns, the underlying issue needs repair.

What does 45 mean?

When you see error code 45 on your Noritz tankless water heater, it means the unit has detected a water leak somewhere in the system. This could be due to a loose connection, a cracked pipe, or a faulty component. The heater has safely shut down to prevent further water damage. While it's still safe to use, it's important to have a professional inspect and repair the issue as soon as possible.

Affected Models

Replacement Parts

PartOEM NumberEst. Cost
Water Inlet Valve NOR-WIV-20
Water Outlet Valve NOR-WOV-20
Heat Exchanger

Related Codes on Same Models

CodeDescriptionSeverity
10 Flame Failure Warning
11 Ignition Failure Warning
14 Thermal Fuse Failure Warning
29 Condensate Drain Issue Warning
31 Inlet Thermistor Failure Warning
32 Outlet Thermistor Failure Warning
33 Heat Exchanger Thermistor Failure Warning
43 Water Level/Neutralizer Issue Warning
51 Fan Motor Failure Warning
61 Fan Motor Failure Warning