Sleep Mode; Fault Conditions; Over-Temperature Condition; Under-Temperature Condition - 3M Bair Hugger 675 Service Manual

Standby Mode
The Standby mode is a temporary state that lasts a maximum of 10 seconds and the
Bair Logo is displayed on the LCD screen.
To enter Standby mode, press the Power button from Sleep mode.
To exit Standby mode, either: a) Press the Bair Logo for three seconds to enter
Diagnostic mode; or b) Wait 10 seconds and the unit will go into Sleep mode.
Sleep Mode
During Sleep mode, the warming unit is idle and awaiting user activation. When in
Sleep mode the following events occur:
• System timer remains active.
• The LCD goes blank.
• The Power indicator illuminates amber.
To enter Sleep mode, press the Power button from either the Diagnostic mode or
Operation mode.
To exit Sleep mode, either: a) Press the Power to enter Standby mode; or, b) Press a
temperature button to enter Operation mode.
Fault Conditions
The Model 675 warming unit's software recognizes several nonhazardous fault
conditions including:
• Sensor failures.
• Microprocessor failures.
• Software failures.
• Keypad failures.
• Power supply failure.
• Temperature out of range.
When a fault condition exists, the following events occur:
• Blower turns off.
• Heater turns off.
• Audible alarm sounds.
• Fault wrench appears on LCD screen.
• Fault code appears on LCD screen.
• Up to 20 fault codes are stored in memory.
Silence Alarm/Reset Unit
• When the audible alarm sounds, press the Power button on the keypad to
silence it.
• The warming unit must be unplugged before it can be used. See "Viewing the
Fault Code Log" and the "Fault Code Table" for more information about specific
fault codes.
Over-Temperature Condition
An independent electronic thermal cutoff safety circuit shuts the heater off to ensure
the hose end air remains below 56°C if an over-temperature condition is detected. An
over-temperature condition occurs when one of the following is detected:
1. The independent thermal cutoff safety circuit senses the air exiting the unit
exceeds 53°C [±3°C].
2. The temperature exceeds 47°C for 30 seconds.
3. The temperature is 3°C above set point for 3 minutes.
When an over-temperature condition exists, the following events occur:
• Over-temperature indicator and fault
condition wrench alternate displaying
in the LCD screen.
• Audible alarm sounds.
• Blower and heater turn off.
The warming unit must be unplugged before it can be used.
Under-Temperature Condition
An under-temperature condition occurs when the warming unit detects the
temperature set point has not been reached or maintained during use. It occurs when
the temperature is less than 3°C below the selected temperature for 3 minutes.
When an under-temperature condition exists, the following events occur:
1. Under-temperature indicator and fault
condition wrench alternate displaying
in the LCD screen.
2. Audible alarm sounds.
3. Blower and heater turn off.
The warming unit must be unplugged before it can be used.
English / 34-8720-2487-1
Diagnostic Mode
The Bair Hugger Model 675 has a diagnostic mode that allows access to the service
and calibration utilities of the unit. You will need to access the diagnostic menu for
several service procedures described in this manual.
To access Diagnostic mode, press and hold the Diagnostic Mode button (i.e. Bair
Logo) for three seconds. The Diagnostic Mode, Ambient, 32, 38, and Power buttons
are used to access Diagnostic mode, navigate through the Diagnostic Menu items, and
exit Diagnostic mode. The figure and accompanying table below show the front panel
button locations and functions used in Diagnostic mode.
Access Diagnostic
Mode/Main Menu
Select Menu
Item
Bair Hugger Button Functions in Diagnostic Mode
Button
• Hold for 3 seconds to access Diagnostic mode. The warming
unit must be in Standby mode or Fault mode to access
Diagnostic
Diagnostic mode.
Mode
• When in any Diagnostic mode screen, press to go to the
Diagnostic Menu.
32
• Scroll down a Diagnostic Menu item
38
• Scroll up a Diagnostic Menu item
Ambient
• Select a Diagnostic Menu item.
• Exit Diagnostic mode and return the warming unit to
Power
Sleep mode.
The figure below illustrates the Diagnostic Mode menu structure and the associated
menu items.
DIAGNOSTIC MENU
Scroll Down Scroll Up
DIAGNOSTICS MENU
FILTER TIMER
CALIBRATION
SYSTEM TEST
OT TEST
Diagnostic
Mode
Action When Pressed
FILTER TIMER
CALIBRATION
SYSTEM TEST
43C
170W
340W
680W
OT TEST
SYSTEM INFO
FAULT LOG
BLOWER TIMER
Exit
7