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Temp Sensor Out Of Range, Check For Bad ConnectionsBunn

Bunn Temp Sensor Out Of Range, Check For Bad Connections

The temperature sensor circuit reads open — the probe or its wiring is disconnected.

Source: Bunn/BU-AXIOM_sm.pdf

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What does Bunn Temp Sensor Out Of Range, Check For Bad Connections mean?

On AXIOM digital brewers, this diagnostic message means the temperature sensor probe is reading open. The control board has lost a valid temperature signal, typically because the sensor or one of its connections is broken. The manual pairs this message with the instruction to check for bad connections, pointing to an open temperature-sensor probe rather than a shorted one.

Symptoms

  • Display reads "Temp Sensor Out Of Range, Check For Bad Connections"
  • Brewer cannot read tank temperature
  • Brewer will not reach ready or brew normally
  • No valid temperature shown on the display

Common causes

  • Temperature sensor probe open (failed)
  • Bad or loose connection in the sensor wiring
  • Disconnected sensor lead at the control board

Diagnostic steps

  1. 01

    Inspect the sensor connections

    Check the temperature sensor wiring and connectors for loose, corroded, or disconnected terminals. The manual specifically calls out checking for bad connections on this message.

  2. 02

    Confirm the probe is open

    An open probe is the documented cause. Verify the temperature sensor probe is reading open rather than shorted, which is a different message.

  3. 03

    Replace or repair the temperature sensor

    If the probe is open and connections are good, replace or repair the temperature sensor probe as needed.

  4. 04

    Re-test after repair

    Restore the connection or fit a new probe, then power up and confirm the display reads a valid temperature and reaches ready.

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When to call a professional

Reaching the temperature sensor means working inside a brewer that is heated at all times and carries live line voltage on nearby components. The manual restricts inspection, testing, and repair of electrical equipment to qualified service personnel and warns that shorting terminals can fail the board. Have a Bunn Authorized Service Representative verify the open sensor and replace the probe rather than probing energized circuits yourself.

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Other Bunn error codes

Fill Time Too Long

Tank refill timed out — the brewer could not fill the tank within the allowed time and shut down.

Heating Time Too Long

The tank water failed to reach the ready temperature within the allowed time, so the brewer shut down.

Temperature Too Low

Tank water is below the ready temperature, so brewing is locked out until it heats up.

Temp Sensor Out Of Range, Check Wire For Shorts

The temperature sensor circuit reads shorted — the sensor wiring is shorted.

WARNING INACCURATE FLOW - TOO MUCH LIME PLEASE REPAIR

The brewer detected inaccurate water flow caused by heavy lime buildup and is asking for descaling/repair.

WARNING VERY LOW FLOW - PLEASE REPAIR

The brewer detected very low water flow caused by lime buildup and is asking for descaling/repair.

CHECK SPRAYHEAD FOR LIME - CHECK FITTINGS FOR LIME

Maintenance message prompting the operator to delime the sprayhead, valve, and tank.

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