XIII. INTEGRATED GAS CONTROLLER (IGC) OPERATION
NOTE: The default value for the evaporator-fan motor ON and OFF delay is 45 seconds. The Integrated Gas Controller (IGC) modifies this value when abnormal limit switch cycles occur. Based upon unit operating conditions, the ON delay can be reduced to 0 seconds and the OFF delay can be extended to 180 seconds.
When one flash of the LED (light-emitting diode) is observed, the evaporator-fan ON/OFF delay has been modi- fied. If the limit switch trips at the start of the heating cycle during the evaporator ON delay, the time period of the ON delay for the next cycle will be 5 seconds less than the time at which the switch tripped. (Example: If the limit switch trips at 30 seconds, the evaporator-fan ON delay for the next cycle will occur at 25 seconds.) To prevent short-cycling, a 5-second reduction will only occur if a minimum of 10 min- utes has elapsed since the last call for heating.
The evaporator-fan OFF delay can also be modified. Once the call for heating has ended, there is a 10-minute period dur- ing which the modification can occur. If the limit switch trips during this period, the evaporator-fan OFF delay will increase by 15 seconds on the next cycle. A maximum of 9 trips can occur, extending the evaporator-fan OFF delay to 180 seconds. To restore the original default value, reset the power to the unit.
A. To Shut Off Unit
Set system selector switch at OFF position. Resetting heat- ing selector lever below room temperature will shut unit off temporarily until space temperature falls below thermostat setting.
XIV. SAFETY RELIEF
A soft-solder joint at the suction line Schrader port provides pressure relief under abnormal temperature and pressure conditions.
XV. VENTILATION (Continuous Fan)
Set fan and system selector switches at ON and OFF posi- tions, respectively. Evaporator fan operates continuously to provide constant air circulation. When the evaporator-fan selector switch is turned to the OFF position, there is a 30-second delay before the fan turns off.
XVI. ECONOMI$ER+ CONTROLLER
The EconoMi$er+ controller is mounted to the top of the EconoMi$er+ damper and is accessible by removing the filter access door of the unit.
The EconoMi$er+ controller is protected by a sheet metal enclosure mounted over the controller. Remove the single screw on the front of the enclosure and lift off the top for access to the controller. The primary purpose of the control- ler is to provide control of the EconoMi$er+ dampers and the cooling compression stages. The status of the indoor fan is monitored through the G input but is not directly controlled by the controller. The heating function is completely inde- pendent of the controller.
IMPORTANT: The controller can only be used with conven- tional thermostats with Y1, Y2 and G input to the controller; it can NOT be used with electronic thermostats with a pro- portional room temperature input, or with Variable Air Vol- ume systems.
There are 4 LEDs on the controller, which are used to read val- ues and display status and configuration information. There are 2 buttons (READ/ADJUST and ADVANCE/MANUAL), which change modes and configure the controller. See Fig. 36.
The EconoMi$er+ microprocessor based control system pro- vides the following control functions:
•EconoMi$er+ damper control for free cooling
•Minimum position control for ventilation
•Demand Ventilation Control using a CO2 sensor
•Compressor Cooling Stage Control
•Occupied/Unoccupied Control
•Diagnostics Display and History
•Manual test control
See Table 32 for Inputs and Outputs.
A. Integrated Display
The control board includes an integrated display, which is used for the following functions:
•Configuration and setup
•Set point and control adjustment
•Error status and alarm monitoring
•Manual control
•Reading sensor values
There are 5 modes of display operation:
•Startup Mode
•Run Mode
•Read Mode
•Setup Mode
•Manual Mode
External devices are not required to operate and configure the control.
B. Startup Mode
During the first 3 seconds after power is applied to the con- trol, the four LEDs flash as shown in Table 33, indicating that the control is being initialized. The buttons are not operational during Startup mode.
C. Run Mode
Run mode indicates status of controller and unit. The mode can be changed to the Read, Setup, or Manual modes by pushing various buttons.
While the control is in Run mode, the DS1 heartbeat indica- tor LED (red) will flash to indicate the controller is operating properly. The DS2 Econo indicator LED (yellow) will flash whenever economizer is being used for free cooling. The DS3 first stage cooling indicator LED (green) will be on steady indicate demand for stage 1 cooling. The DS4 second stage cooling indicator LED (green) will be on steady to indicate demand for stage 2 cooling.
If the controller is in a different mode, the controller will return to Run mode after 10 minutes of user inactivity or if the READ/ADJUST (#1) and ADVANCE/MANUAL (#2) but- tons are held for at least 3 seconds until all LEDs flash.
D. Read Mode
Read mode is used to check set points (Table 34) and I/O channel status (Table 35). Enter the Read mode by pushing and releasing the READ/ADJUST (#1) button. A user can only enter Read mode from the Run mode (to get to Run mode, press both the #1 and #2 buttons for at least 3 seconds until all LEDs flash). In Read mode, LEDs are not lit until the READ/ADJUST button (#1) is pushed.
NOTE: If the user pushes and holds the READ/ADJUST but- ton (#1) for more than 3 seconds, then the control will go into the Setup mode, indicated by the yellow LED (on steady).
While in Read mode, push button #1 then the DS1 LED (Red) flashes to indicate setup point number as defined in the setup table. The two green LEDs will then show the value of the display item. The DS3 LED will first display the
