Noritz · Water Heater error code
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Guide · Water HeaterMany tankless complaints are water-side: flow below the activation threshold, a clogged inlet screen, low-flow aerators, or scale in the heat exchanger. Gas supply, venting and combustion codes are blocked: diagnose and refer. Read the code first, then work the water side.
Guide · Water HeaterTankless units show the active code on the remote controller and/or a display on the unit. Many keep a short code history and a maintenance or performance data screen (flow, temperatures) reached through the control; how to reach it is on the tech sheet, often stored with the unit. Many errors clear by themselves when water flow stops, so the history matters. Gas, ignition, flame and venting codes are blocked: read them, then refer.
Guide · Water HeaterPower-vent tanks add a 120 V blower, an air pressure switch and often a vent temperature limit. Most no-heat calls are electrical supply, a kinked or water-filled pressure switch tube, condensate in the blower, or a restricted vent. The tech checks power and the low-voltage safety chain and inspects visually; gas valve, burner, igniter/flame sensor and vent repairs are referred to a licensed gas technician.
Noritz · Water Heater
05
Service due warning
Noritz · Water Heater
10
Combustion / exhaust problem
Noritz · Water Heater
11
Ignition failure
Noritz · Water Heater
12
Flame loss / weak flame
Noritz · Water Heater
14
Thermal fuse tripped (heat exchanger overheat)
Noritz · Water Heater
16
Outlet temperature spike (often scale)