3M Bair Hugger™ Model 775 Temperature Management Unit Service Manual

Introduction

The 3M™ Bair Hugger™ brand Total Temperature Management system comprises the Model 775 forced-air temperature management unit, an optional rolling stand, and disposable components such as Bair Hugger forced-air blankets, the 3M™ 241™ blood/fluid warming set, and Bair Paws™ patient warming gowns.

The warming unit connects to blankets or gowns via a flexible hose, delivering warm air. For fluid warming, the Model 241 set is integrated into the hose.

This service manual provides operating and service instructions, along with unit specifications for the Model 775. It is intended for use in clinical settings to manage patient temperature, preventing or treating hypothermia, or providing comfort when patients are too warm or too cold. The system is suitable for adult and pediatric patients.

Refer to the Instructions for Use (IFU) included with disposable components for specific application details. The Bair Hugger system should only be operated by trained medical professionals.

Definition of Symbols

The following symbols may appear on the product's labeling or packaging:

Explanation of Signal Word Consequences

WARNING: Indicates a hazardous situation which, if not avoided, could result in death or serious injury.

CAUTION: Indicates a hazardous situation which, if not avoided, could result in minor or moderate injury.

NOTICE: Indicates a situation which, if not avoided, could result in property damage only.

Indications

The Bair Hugger system is intended to prevent and treat hypothermia. The Model 775 Temperature Management System can also provide patient thermal comfort when conditions may cause patients to become too warm or too cold. It is suitable for use with adult and pediatric patients.

Contraindications

Do not apply heat to lower extremities during aortic cross-clamping. Thermal injury may occur if heat is applied to ischemic limbs.

Warnings

1. Do not leave patients with poor perfusion unmonitored during prolonged warming therapy sessions. Thermal injury may result.
2. The Bair Hugger temperature management unit is designed to operate safely ONLY with 3M Patient Warming disposable components. Use with other products may cause thermal injury. (To the full extent permitted by law, the manufacturer and/or importer declines all responsibility for thermal injury resulting from the unit being used in conjunction with products other than 3M Patient Warming products.)
3. Do not warm patients with the temperature management unit hose alone. Thermal injury may result. Always connect the hose to a Bair Hugger blanket or Bair Paws gown before providing therapy.
4. Do not place the non-perforated side of the blanket on the patient. Thermal injury may result. Always place the perforated side (the side with small holes) towards the patient.
5. Do not continue temperature management therapy if the Over-temp indicator light illuminates and the alarm sounds. Thermal injury may result. Unplug the unit and contact a qualified service technician.
6. Do not continue 241 blood/fluid warming therapy if the Over-temp indicator light illuminates and the alarm sounds. Immediately stop fluid flow, and discard the blood/fluid warming set. Unplug the temperature management unit and contact a qualified service technician.
7. Do not use a forced-air warming device over transdermal medication. Increased drug delivery and patient injury or death may occur.
8. Do not allow the patient to lie on the warming unit hose or allow the hose to directly contact the patient's skin during patient warming; thermal injury may result.
9. Reusable blankets made from woven fabric, or blankets without discrete, visible holes, can cause the safety system of this unit to fail, which may result in serious thermal injury. This warming unit has been designed to operate safely ONLY with Bair Hugger blankets and Bair Paws gowns.
10. Do not connect a Bair Hugger blanket, 241 blood/fluid warmer, or Bair Paws gown to the warming unit if it has been cut or damaged; thermal injury may result.
11. Do not use a Bair Hugger blanket to transfer or move the patient; injury may result.
12. To reduce the risks associated with hazardous voltage and fire:
    • Keep power cord visible and accessible at all times. The plug on the power cord serves as the disconnect device. The wall socket outlet shall be as close as practical and shall be easily accessible.
    • Use only the power cord specified for this product and certified for the country of use.
    • Do not allow the power cord to get wet.
    • Do not use the warming unit when it appears the warming unit, power cord or any component is damaged. Contact 3M Patient Warming Technical Support at 1-800-733-7775.
13. This equipment must only be connected to a supply mains with protective earth.
14. To reduce the risks associated with exposure to biohazards, always perform the decontamination procedure prior to returning the warmer for service and prior to disposal.
15. Do not retain the patient using a warming blanket alone, as injury may result. Use a draw, sheet, safety strap, or other means to retain the patient.
16. Do not modify this equipment without authorization of the manufacturer.
17. To ground this Bair Hugger warming unit, only connect to receptacles marked “Hospital Only,” “Hospital Grade,” or a reliable grounded outlet.

Cautions

1. Except for specific blanket models, Bair Hugger blankets are not sterile and are all intended for single patient use ONLY. Placing a sheet between the Bair Hugger blanket and the patient does not prevent contamination of this product.
2. Monitor the temperature and cutaneous response of patients who are incapable of reacting, communicating and/or who are without a sense of feeling every 10-20 minutes or according to institutional protocol. Monitor the patient's vital signs regularly. Adjust air temperature or discontinue therapy when the therapeutic goal is reached or if vital sign instability occurs. Notify physician of vital sign instability immediately.
3. Do not leave pediatric patients unattended during therapy.
4. Do not initiate temperature management therapy unless the temperature management unit is free from mechanical damage and is safely placed on a hard surface or securely mounted. Otherwise, injury may result.
5. To prevent tipping, clamp the Model 775 temperature management unit to an IV pole at a height that provides stability. We recommend clamping the unit no higher than 44" (112 cm) on an IV pole with a minimum 28" (71 cm) diameter wheelbase. Failure to do so may result in IV pole tipping, catheter site trauma, and patient injury.
6. Electrical shock hazard. Do not disassemble the temperature management unit unless you are a qualified service technician. There are electrically live parts within the unit when it is connected to a power source, even when the unit is in Standby mode.
7. To reduce the risks associated with environmental contamination, follow applicable regulations when disposing of this device or any of its electronic components.

Notices

1. The Bair Hugger temperature management unit meets medical electronic interference requirements. If radio frequency interference with other equipment should occur, connect the unit to a different power source.
2. Federal law (USA) restricts this device to sale by or on the order of a licensed healthcare professional.
3. To avoid Bair Hugger warming unit damage:
   • Do not immerse the Bair Hugger warming unit or warming unit parts or accessories in any liquid or subject them to any sterilization process.
   • Do not use solvents such as acetone or thinner to clean the warming unit; avoid abrasive cleaners.
   • Clean warming unit exterior with soft cloth using plain water or a mild, all-purpose or nonabrasive cleaner.

Proper Use and Maintenance

3M Patient Warming assumes no responsibility for the reliability, performance, or safety of the temperature management unit if the following events occur:

• Modifications or repairs are performed by unqualified personnel.
• The unit is used in a manner other than that described in the Operator's or Service Manuals.
• The unit is installed in an environment that does not meet the appropriate electrical and grounding requirements.

Read Before Servicing Equipment

All repair, calibration, and servicing of the Bair Hugger Model 775 temperature management unit require the skill of a qualified, medical equipment service technician who is familiar with good practice for medical device repair. If service does not require the manufacturer's attention, the Model 775 Service Manual provides the technical information needed to service the unit, or 3M Patient Warming will provide that information on request. Perform all repairs and maintenance in accordance with the instructions in the Service Manual.

Safety Inspection

Perform a safety inspection after making repairs to the Bair Hugger Model 775 Temperature Management Unit and before returning the unit to service. A safety inspection should include calibrating the operating temperature settings and testing the over-temperature detection function as described in this service manual, as well as testing for leakage current and continuity check on safety ground.

Overview

When you connect the Bair Hugger Model 775 Temperature Management Unit to a grounded power source, the unit automatically performs the power-on-reset operation. Following this, the unit enters Standby mode. You can select any operating mode by pressing the appropriate button on the unit's control panel.

Unit Power-On-Reset

The Bair Hugger Model 775 performs the following sequence upon connection to a grounded power source:

• Performs self-test functions.
• Momentarily illuminates indicator lights and all pixels in the alphanumeric display.
• Displays "MD 700's" and the software revision level.
• Sounds an alarm (three low-level clicks).
• Enters Standby mode with the high fan setting selected by default.

Note: The low fan setting indicator light does not illuminate during power up.

If power is lost for less than 1 second, the unit returns to the previous operating mode. If power is lost for longer than 1 second, the unit resets and enters Standby mode with the high fan setting selected by default.

Operating Modes

The Model 775 has 4 operating modes: Ambient, 32°C, 38°C, and 43°C. Select a mode by pressing the corresponding button.

After selecting a temperature mode, the following occur:

• Corresponding indicator light illuminates.
• Blower operates.
• Heater activates (except in Ambient mode).
• Temperature mode timer and hour meter activate.
• Temperature at the blanket-end of the hose appears in the alphanumeric display.
• The "Temp in Range" indicator illuminates when the hose end temperature is within ±1.5°C of the selected setting (does not illuminate in Ambient mode).

Airflow Modes

The Model 775 has two preset fan speed settings: a default high fan setting (?⬆️) and a reduced low fan setting (?⬇️). The unit defaults to the high fan setting upon power-up or when Standby is selected. The low fan setting can be pre-selected while in Standby.

Standby Mode

Press the Standby button to enter Standby mode. In this mode:

• Standby indicator light illuminates.
• Blower and heater turn off.
• Alphanumeric display deactivates.
• Temperature mode timer pauses.
• Alarm and fault detection functions remain active.

Fault Conditions

The Model 775 software recognizes several nonhazardous fault conditions, including:

• Sensor failures
• Heater failures
• Computer failure
• Software failure
• Keypad failure
• Power supply failure
• Blower motor failure
• Forced over-temperature test failure

When a fault condition occurs:

• Fault indicator light flashes.
• Audible alarm sounds.
• Blower heater turns off.
• Fault code appears in the alphanumeric display.
• Up to 5 fault codes are stored in memory.

Press any button on the keypad to temporarily silence the audible alarm. The unit must be unplugged before restarting. Refer to "Viewing the Fault Code Log" (page 16) and "Fault Code Table" (page 17) for details.

Over-Temperature Condition

When an over-temperature condition occurs:

• Over-temp indicator light flashes.
• Audible alarm sounds.
• Blower and heater turn off.
• Fault code appears in the alphanumeric display (see page 17).

Press any button on the keypad to temporarily silence the audible alarm. The unit must be unplugged before restarting.

Alternative Modes

The Bair Hugger Model 775 has 5 alternative modes for accessing service and calibration utilities:

Hour Meter: Displays cumulative operating time in whole hours.

Calibration: Allows technicians to check and adjust hose end sensor calibration (max ±3.0°C offset). Operates in Ambient mode, displaying current sensor temperature and offset.

Fault Code Log: Displays the last 5 fault codes stored in system memory. Refer to the "Fault Code Table" (page 17).

System Information: Displays firmware, system ID, serial port baud rate, 5V power supply status, and control board serial number.

Over-temperature Detection Test: Allows testing of the independent over-temperature shutdown system.

Accessing the Alternative Modes

Press the unlabeled "Alternative Mode" button (located on the front panel, often by pressing the Bair Hugger logo) in combination with an operating mode button. The display will show "Hold for AltModeX".

Exiting an Alternative Mode

Press the alternative mode button again or wait for 60 seconds.

Service Procedures

Calibrating the Operating Temperature

CAUTION: Perform all temperature testing with an 3M Patient Warming Model 22110 Temperature Test Unit. Improper adjustments can lead to patient injury.

Service frequency: Every 6 months or 500 hours of use, or whenever service is performed.

Tools/equipment: Model 22110 Temperature Test Unit, calibrated thermometer (accepting male, subminiature connector, K style thermocouple).

Method:

1. If the unit was stored below 20°C, allow it to reach ambient temperature.
2. Attach the Model 22110 temperature test device to the unit's hose end.
3. Connect the unit to a grounded power source. It will self-test and enter Standby mode.
4. Press the Ambient button. Allow the unit to run for at least 10 minutes to equalize internal components. Ensure the high fan setting (?⬆️) is active.
5. Press the Alternative Mode button and Ambient button simultaneously for 3 seconds to enter Calibration mode. The unit will display "TMP" and the hose end temperature, followed by "OS" and the calibration offset.
6. Compare the displayed temperature with the Model 22110 test device.
7. If temperatures do not match, adjust using the 32°C button (decrease) or 38°C button (increase) in 0.1°C increments. Adjustment range is ±3.0°C.
8. Press the Alternative Mode button to store the offset and return to Standby mode.

Note: If an offset greater than ±3°C is needed, the hose end sensor may be defective. Remove the unit from service.

Testing the Over-Temperature Detection System

WARNING: Do not perform this test while the unit is in use for therapy. Thermal injury may result.

CAUTION: Connect each warming unit to a separate power source.

Service frequency: Every 6 months or 500 hours of use, or whenever service is performed.

Tools/equipment: Model 22110 Temperature Test Unit.

Method:

1. Connect the unit to a grounded power source. It will self-test and enter Standby mode.
2. Connect the temperature test kit to the unit's hose.
3. Press the Ambient button and let the unit run for 5 minutes. Ensure the high fan setting (?⬆️) is active.
4. Press the Alternative Mode button and the 43°C button simultaneously for 3 seconds to enter Over-Temperature Detection Test mode. The unit will perform the following:
   • Blower remains ON.
   • Heater elements turn ON at full power.
   • 43°C indicator light flashes.
   • Over-temperature timer activates.
   • "OT Test" flashes in the alphanumeric display.
5. Wait for the test to complete. The unit will then turn off heater elements while the blower continues.
6. View the alphanumeric display for test outcome:
   • PASS: Over-temperature detected within 150 seconds. Alarm sounds (2 beeps). Display shows "PASS", "OT Test PASS-Prx OR PASS-Dst", "TestTime XX Secs", "Unplug To Reset".
   • FAIL: Over-temperature not detected within 150 seconds (time-out). Alarm sounds, Fault indicator flashes. Display shows "FAIL", "OT Test FAIL", "TestTime 150 Secs", "Unplug To Reset".

Note: Do not return a unit to service if it fails this test. Send it back to 3M Patient Warming for repair. See "Returning Units for Service" (page 26).

7. Record the maximum temperature displayed by the test kit (use "Maintenance Log"). If the temperature is above 56°C, contact 3M Patient Warming technical service.
8. After the test, allow the unit to cool by running it for at least five minutes.
9. Unplug the unit to reset it to normal operation.

Viewing the Fault Code Log

Service frequency: As often as necessary.

Tools/equipment: None required.

Method:

1. If the unit is ON, access the log from any operating mode. Otherwise, connect to a grounded power source, let it self-test and enter Standby, then select an operating mode.
2. Press the Alternative Mode button and the 32°C button simultaneously for three seconds to enter Fault Code Log mode. The unit continues in its current operating mode, and the 32°C and 38°C indicator lights flash.
3. The display shows "FC(n) XXX", where "FC" is fault code, "n" is the order in the log, and "XXX" is the code. The time of the fault (HH:MM:SS or hours:minutes) appears below.
4. Press the 32°C or 38°C button to view the next fault code. The unit stores up to 5 fault codes.
5. Press the Alternative Mode button to return to the previous operating mode.

Clearing the Fault Code Log

Enter Fault Code mode (press Alternative Mode and 32°C buttons for 3 seconds), then press the 43°C button.

Note: The fault code log should only be cleared when instructed by a 3M Patient Warming representative.

Fault Code Table

The software detects and reports the following conditions with corresponding fault codes:

Viewing the Hour Meter

Service frequency: As often as necessary.

Tools/equipment: None required.

Method:

1. If the unit is ON, begin from any operating mode. Otherwise, connect to a grounded power source, let it self-test and enter Standby, then select an operating mode.
2. Press the Alternative Mode button for 3 seconds. The unit enters Hour Meter Display mode.
3. The display shows "Hours" and the cumulative operating hours in whole numbers.
4. Wait 60 seconds or press the Alternative Mode button to return to the previous operating mode.

Viewing the Operating Timer

To view the operating time in the current temperature mode, press and hold the current temperature mode button for at least 3 seconds. The time is displayed in HH:MM:SS format.

Replacing the Air Filter

Service frequency: Every 12 months or 500 hours of use.

Tools/equipment: Replacement air filter, #2 Phillips screwdriver.

WARNING: Do not attempt to clean the air filter as it may contain hazardous microorganisms. Discard the filter according to institutional protocol for biohazardous material.

Method:

1. Disconnect the unit from the grounded power source.
2. Turn the unit upside down.
3. Remove the 2 screws in the louvered filter cover.
4. Lift the filter cover off.
5. Remove and discard the old air filter.
6. Place the new filter in the compartment with the gasket toward the filter ledge.
7. Replace the filter cover with louvers facing the back of the unit.
8. Replace the 2 screws in the filter cover.

Replacing the Hose

Service frequency: As needed.

Tools/equipment: Replacement hose, Needle-nose pliers, Strap wrench (optional).

Detaching Hose

1. Disconnect the unit from the power source.
2. Unscrew the hose collar.
3. Slide the hose out of the unit. The hose will still be attached by a cable.
4. Carefully detach the cable connector from the header plug inside the hose connector using hand or needle-nose pliers.

Reattaching Hose

1. Attach the cable connector of the new hose to the header plug, aligning protrusions with slots.
2. Align the flat section of the hose end with the corresponding flat part of the unit's hose connector and slide the hose into the unit.
3. Firmly screw the hose collar back into place.
4. Reconnect the unit to a grounded power source.
5. Calibrate operating temperature settings. See page 12.
6. Perform over-temperature detection system test. See page 14.

Replacing the Fuses

Service frequency: As needed.

CAUTION: Use proper Electrostatic Discharge (ESD) procedures to prevent damage to the unit.

Tools/equipment: Phillips screwdriver, Wire cutter, Wire tie, Needle-nose pliers.

Disassembling the Unit

1. Detach the hose (see page 20).
2. Turn unit upside down.
3. Using a Phillips screwdriver, remove the eight screws securing the top and bottom enclosures.
4. Turn unit upright.
5. Remove four screws attaching the upper enclosure to the back plate.
6. Lift the upper enclosure straight up and disconnect the user interface wire by squeezing release tabs.
7. Replace fuses.

Reassembling the Unit

1. Install the replacement heater facing the same direction as the removed one.
2. Reinstall the four heater screws.
3. Slide the heater duct/PCB assembly back onto the chassis.
4. Secure the heater duct with two screws.
5. Reconnect the two motor wires.
6. Reconnect the power, heater, and elbow wires.
7. Secure the heater wire to the PCB with a new wire tie. Note: Be careful not to damage the component the wire is secured to, as it is very fragile.
8. Ensure power and heater wires are routed away from each other.
9. Reconnect the UI wire and slide the upper enclosure over the chassis.
10. Reinstall the four enclosure screws to attach the upper enclosure to the back plate. Push down on the top of the unit when tightening to attain proper sealing.
11. Flip the unit upside down and replace the eight enclosure screws. Tighten fully to ensure proper seal and prevent noise. If using a power screwdriver, increase torque setting. A whistling noise may indicate loose screws.
12. Reattach the hose (see page 20).

General Maintenance and Storage

Cleaning the Warming Unit

Service frequency: As needed.

Tools/equipment: Soft cloth lightly dampened with water, Mild detergent or antimicrobial spray, Dry soft cloth.

WARNING: Do not immerse the cabinet or hose while cleaning. Moisture will damage the components, and thermal injury may result.

CAUTIONS:

• Do not use a dripping wet cloth to clean the cabinet. Moisture may seep into electrical contacts and damage components.
• Do not use alcohol or other solvents to clean the cabinet. Solvents may damage labels and other plastic parts.

Method:

1. Disconnect the unit from the power source before cleaning.
2. Wipe the cabinet and the outside of the hose with a damp, soft cloth and a mild detergent or antimicrobial spray.
3. Dry with a separate soft cloth.

Storage

Store all components in a cool, dry place when not in use.

Troubleshooting

The Model 775 software routinely checks for unusual operating conditions. If a fault occurs, the system may trigger a fault condition and alarm. The unit can be reset by disconnecting it from the main power source for 30-60 seconds. If the fault recurs, the unit may have a hard-fault or permanent error.

Call Technical Support for Replacement Parts at 1-800-733-7775.

Permanent errors – a fault condition always occurs at turn on or after pressing a temperature setting

Cautionary Errors – Fault condition while unit is in use

Technical Support and Customer Service

USA, Worldwide

TEL: 800-733-7775, 952-947-1200

FAX: 800-775-0002, 952-947-1400

When You Call for Technical Support

We will need the serial number of your Bair Hugger temperature management unit. The serial number label is located on the back or side of the unit.

In-Warranty Repair and Exchange

USA

Call 3M Patient Warming customer service for factory service. A customer service representative will provide a Return Authorization (RA) number. Use this RA number on all correspondence. A shipping carton can be provided if needed. Contact your local supplier or sales representative to inquire about borrowing a unit while yours is serviced.

OUTSIDE THE USA

Contact your local distributor concerning in-warranty repair and exchange.

Returning Units for Service

Tools/equipment: 3M Patient Warming service carton, Tape dispenser, Shipping label, Marking pen.

Method:

1. Call Technical Support (see page 25) to get a Return Authorization (RA) number and a service carton.
2. Remove the top foam piece. If a plastic liner is available, use it to enclose the unit.
3. Lower the unit carefully into the carton.
4. Replace the top foam piece, observing proper orientation. The hose will extend out in the corner of the foam.
5. Lay the unit hose on top of the foam piece around the edge.
6. Seal the carton with tape.
7. Apply the shipping label addressed to 3M Patient Warming.
8. Write the RA number on the outside of the carton.
9. Ship to 3M Patient Warming.

Specifications

Physical Characteristics

Temperature Characteristics

Safety System

Electrical Characteristics

Maintenance Checklist

Filter inspection

1. Remove and inspect the filter.
2. Return filter or replace as necessary. Note: Replace every 12 months or every 500 hours (PN 90047).

Calibrate the operating temperature

1. Attach the Bair Hugger temperature test unit (PN 22110).
2. Connect temperature sensor to your meter.
3. Run in Ambient mode for 10 minutes.
4. Enter the calibration mode: Press the Alternate Mode button and Ambient button, together for approximately 3-seconds.
5. Temperature measured at end of hose will display on LCD.
6. Adjust Bair Hugger unit's displayed temperature so it matches test unit sensor (±.1° increments).
   • 32° button lowers displayed temperature.
   • 38° button raises displayed temperature.
   Note: Unit can only adjust ± 3.0°C. Try a different hose if more adjustment is required and call 3M Patient Warming technical support with results.
7. Save Settings – Press the Alternate Mode button to save your settings.

Test over temperature detection system

1. Initiate over-temperature test:
   • Press the Alt and 43°C button together for approximately 3-seconds.
   • Wait as unit executes self test.
   • Two beeps indicate test has completed.
2. Review Results:
   • Observe max temperature ≤56°C.
   • Pass or fail indicated on display.

Maintenance Log

Record maintenance actions and hour meter readings here.

Legal and Copyright Information

CE 0086

Made in the USA by 3M Health Care.

3M is a trademark of 3M Company, used under license in Canada. BAIR HUGGER, BAIR PAWS, 241, TOTAL TEMPERATURE MANAGEMENT and the BAIR HUGGER logo are trademarks of Arizant Healthcare Inc., used under license in Canada. ©2013 Arizant Healthcare Inc. All rights reserved.

EC REP: 3M Deutschland GmbH, Health Care Business, Carl-Schurz-Str. 1, 41453, Neuss, Germany

3M Health Care, 2510 Conway Ave., St. Paul, MN 55144 USA

TEL 800-228-3957 | www.bairhugger.com

202526A 07/13