14
INSSCV1217
CIR-028 CONTROL BOARD FUNCTIONS
The
CIR-028
control board is used with all air handler models using an ECM motor with a local control box. The following figure represents the
control board:
Input and output descriptions
The terminal block of the control unit fan housing (shown on the right side of Fig. 14) has the following inputs and outputs:
• R: 24Vac output (18VA max) can supply an external controller or thermostat
• C: Common internal transformer
• 1: Airflow #1 control signal (24Vac)
• 2: Airflow #2 control signal (24Vac)
• 3: Airflow #3 control signal (24Vac)
Priority input controls
Input controls activate speed airflow prioritizing the highest selected. If the airflow #1 input is ajusted to 500 CFM and airflow #2 is set to 700 CFM,
and both are activated simultaneously, airflow #2 set to 700CFM will be prioritized.
Airflow adjustment
The control board has three (3) independent adjustable inputs (see Fig. 13). To adjust the corresponding input to the desired airflow, turn the knob
to the desired airflow. Pilot lights indicate which, if any, input is activated. It should be noted that only the highest active airflow will be prioritized.
TYPICAL THERMOSTAT CONNECTION
The following figure shows a typical connection with a 24Vac thermostat. For more clarity, the air handler cabinet is not shown here. If needed,
refer to Fig. 9 to see the entire connection path.
24V
CONNECT TO
ECM MOTOR
(UNDER COVER)
R
R
C
1
1
2
2
3
3
THERMOSTAT
R
C
Y
W
G
FROM ECM MOTOR
R
R
C
1
1
2
2
3
3
R
C
Y
W
G
AIR
HANDLER
THERMOSTAT
FIG. 14
FIG. 15
