312 🟡 Repair Required
Takagi Error Code 312: Outlet Temp Sensor
⚠️ The tankless water heater has shut down due to a problem with the outlet temperature sensor. This will prevent hot water from being produced until the issue is resolved.
How to Fix Takagi Code 312
- Step 1: Reset the unit by turning off the power at the breaker for 30 seconds, then turn it back on. This may clear a temporary error.
- Step 2: Check the display for the error code again. If it reappears, the problem persists.
- Step 3: Contact a qualified HVAC technician to diagnose and repair the issue. Do not attempt to disassemble the unit yourself.
What Does Takagi Error Code 312 Mean?
The Takagi 312 error code indicates a problem with the outlet temperature sensor. This sensor monitors the temperature of the water as it leaves the heat exchanger. The control board uses this reading to modulate the burner and maintain a consistent output temperature. If the control board doesn't receive a valid signal from this sensor, it will shut down the unit as a safety measure. This prevents the unit from overheating or delivering water at an unsafe temperature. A faulty sensor, wiring issues, or even a problem with the main control board can trigger this error. Because the unit has locked out, you will not have hot water until the problem is resolved.
Common Causes of Takagi Code 312
- Faulty outlet temperature sensor
- Loose or corroded wiring connections to the outlet temperature sensor
- Wiring harness damage between the sensor and the main control board
- Sediment or scale buildup on the sensor, affecting its accuracy
- Main control board failure
Applicable Takagi Models
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Find a Licensed Tech Near You →Replacement Parts for Takagi HVAC System Code 312
Outlet Temperature Sensor OEM: TK190047
Main Control Board