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Temperature sensor fault: tankless water heater / continuous flow hot water system codes by brand
A temperature sensor reading is missing or out of range.
| Brand | Code | Meaning | What you can do |
|---|---|---|---|
| Rinnai | 32 | Outgoing water temperature sensor fault | Call a pro |
| Rinnai | 33 | Heat exchanger thermistor fault | Call a pro |
| Rinnai | 34 | Temperature sensor fault (depends on model) | Call a pro |
| Rinnai | 36 | Lower tank thermistor fault | Call a pro |
| Rinnai | 38 | Exhaust temperature thermistor fault | Call a pro |
| Rinnai | 41 | Frost protection (ambient) sensor fault | Call a pro |
| Rinnai | 51 | Inlet water thermistor fault | Call a pro |
| Navien | E047 | Exhaust temperature sensor fault | Call a pro |
| Navien | E407 | Hot water outlet temperature sensor fault | Call a pro |
| Navien | E421 | Cold water inlet temperature sensor 1 fault | Call a pro |
| Navien | E432 | Cold water inlet temperature sensor 2 fault | Call a pro |
| Navien | E441 | Hot water inlet temperature sensor 2 fault | Call a pro |
| Navien | E740 | Outdoor temperature sensor fault | Call a pro |