Digital Outputs Do2 And Do3 - Cooling Inc/Dec Or Stage 1/2 Wiring; Floating Control - Johnson Controls NXA-FCU-01 Installation Manual

DIGITAL OUTPUTS DO2 AND DO3 - COOLING INC/DEC
OR STAGE 1/2 WIRING
NOTE: The rating for these outputs is 0.5 amps at 24VAC.
Digital outputs 2 and 3 must be wired to the Cooling Increment/Cooling Stage
1 and the Cooling Decrement/Cooling Stage 2.

FLOATING CONTROL

If the cooling control is a modulated valve, then DO2 and DO3 are used to
increment and decrement the actuator and open the valve to increase or
decrease the chilled water flow and increase or decrease the cooling output.
DO2 must be wired to Cooling Increment and DO3 must be wired to Cooling
Decrement.
Wiring for the Cooling Increment and Cooling Decrement is shown in Figure
16. To wire DO2 and DO3 for Cooling Increment and Cooling Decrement:
1. Connect the HOT terminal to the Common lead of the actuator motor.
2. Connect the DO2 terminal to the Increment lead of the actuator motor.
3. Connect the DO3 terminal to the Decrement lead of the actuator motor.
J3
HOT
Figure 16. DO2 and DO3 - Cooling Increment and Decrement Wiring.
FCU Controller
DO5 DO4 HOT DO3 DO2 HOT DO1 AO1 AGND
COMMON
ACTUATOR
INCREMENT
MOTOR
DECREMENT
VALVE
Installation Guide
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