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3M Bair Hugger Model 775

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Temperature Management Unit, Patient Warmer

Routine Maintenance[edit | edit source]

  1. Clean air filter: remove any dust with high pressured compressed air or vacuum. 3M recommends to replace the filter every 500 hours or every 12 months.
  2. Calibrate if necessary: set the unit to 43°C and wait for the temperature to become steady, compare to a trusted temperature meter.
  3. Test overtemp alarm: Hold "Bair Hugger logo" and "43°C" buttons. Two beeps indicate the test has completed. The alarm should stop the unit before it hits 56°C

How to Calibrate Operating Temperature[edit | edit source]

3M offers a testing "apparatus" for most accurate readings. It is comprised of a resistance based temperature probe held inside a plastic cylinder with a metal air diffusing filter to even out air flow to the temperature probe. You can purchase from 3M or other seller - CATALOG NUMBER: 22110
  1. Measure air temperature coming out of the hose with a trusted temperature meter
  2. Press and hold "Bair Hugger logo" and "Ambient" buttons until "OS" appears. This is your temperature offset.
  3. Wait for the unit to get to a steady temp, then use the 32°C and 38°C buttons to lower and raise the displayed temperature.
  4. Lastly, adjust the displayed temperature up or down until it matches what you see on your temperature meter

You can only adjust up to 3° or -3°. If your unit is still not reading close to your trusted reference meter, the hose will need to be replaced.

Fault Codes/Solutions
Fault Codes Possible Cause Solution







Faulty hose end sensor at

patient end.

Faulty elbow sensor.

Hose disconnected from


Replace hose

Replace elbow sensor

Calibrate and return to service




Faulty heater element or faulty control board • Verify fan runs in ambient.

• Check continuity of J4 connector wires on control board

White to black

White to blue

White to yellow

If "open", replace heater. Otherwise, replace control board.

FC-050 Defective user interface Replace user interface


EEPROM error Reset microprocessor

Hold "Bair Hugger logo" and "Standby" buttons at the same time, then connect the unit to power.

Release the buttons once the "Standby" light remains on

You will need to recalibrate the unit after this resetting the microprocessor.



Defective control board Replace control board