Model 916/917___________________________________________________________________________Operation
2-1
Section 2 - Operation
2.1 Changing the Control Temperature Set Point
1. Remove the screwdriver on the front left corner of the control
panel.
2. Press and hold in the PRESS-TO-SET key on the control
panel.
3. Using the screwdriver, turn the SET screw until the desired
temperature is displayed. Clockwise lowers the temperature
and counter clockwise raises the temperature. The approved
operating temperature range for the unit is -50°C to -86°C.
2.2 Changing the Over Temperature Alarm Set Point
The following procedure sets the alarm for a precise
temperature during initial set up. If a precise temperature is not
required, set R9 to the desired temperature.
1. Set the unit to operate at the desired alarm point (see Section
2.1) and allow the unit to operate until it reaches the set point.
2. Remove the top two screws securing the control panel and
loosen the bottom two screws. Carefully remove the control
panel.
3. Remove the six screws securing the cover of the box attached
to the inside of the control panel to expose the alarm board.
4. Turn the switch on the control panel to the NORMAL posi-
tion.
5. If the unit alarms, slowly adjust R9 clockwise (warmer) until
the alarm turns off. If the unit is not in alarm, slowly adjust
R9 counterclockwise (colder) until the alarm turns on.
6. The alarm is now set for the desired temperature. Reinstall the
box cover and secure with screws. Carefully install the control
panel to its proper location and secure with screws.
7. Set the unit to the desired control temperature. See Section
2.1.
The unit should NEVER be set to operate below
-86°C.
Figure 2-1, Temperature
Alarm Circuit Board
showing R-9 Control
