IOM 1206-1
29
Unit Controller Operation
Auto Adjusted Ranges
Some settings have different ranges of adjustment based on
other settings:
Special Set Point Operations
The following setpoints are not changeable unless the unit
switch is off:
• Available Modes
• Number of Compressors
• Expansion Valve Type
• Number of Fans
• Fan VFD Enable
The Circuit Mode setpoints should not be changeable unless
the corresponding circuit switch is off.
The Compressor Enable setpoints should not be changeable
unless the corresponding compressor is not running.
EXV Position set point on each circuit follows the actual EXV
position while EXV Control = Auto. When EXV Control =
Manual, the position set point should be changeable.
The Clear Alarms and Network Clear Alarms settings are
automatically set back to Off after being On for 1 second.
Security
All setpoints are protected using passwords. A four-digit
password provides operator access to changeable parameters.
Service level passwords are reserved for authorized service
personnel.
Operator password: 2526
Entering Passwords
Passwords are entered on the first screen on the unit controller,
If the wrong password is entered, a message will temporarily
appear stating this. If no valid password is active the active
password level displays “none.”
Editing Setpoints
After a valid password has been entered at the unit controller,
setpoints may be changed. If the operator attempts to edit a
setpoint for which the necessary password level is not active,
no action will be taken.
Once a password has been entered, it remains valid for 10
minutes after the last key-press on the unit controller.
Cool LWT 1, Cool LWT 2, and Network Cool Set Point
Available Mode Selection
Range
Without Glycol
4.4 to 18.3 °C (39.9 to 65°F)
With Glycol
-9.5 to 18.3 °C (14.9 to 65 °F)
Evaporator Water Freeze
Available Mode Selection
Range
Without Glycol
2.2 to 5.6 °C (36 to 42.1 °F)
With Glycol
-10.8 to 5.6 °C (12.6 to 42.1 °F)
Low Evaporator Pressure Hold and Unload
Available Mode Selection
Range
Without Glycol
669 to 793 KPA (97 to 115 PSI)
With Glycol
407 to 793 KPA (59 to 115 PSI)
Low Ambient Lockout
Fan VFD
Range
= no for all circuits
0 to 18.3 °C (32 to 65 °F)
= yes on any circuit
-23.3 to 18.3 °C (-9.9 to 65 °F)
