Discrete Control - Johnson Controls NXA-FCU-01 Installation Manual

DISCRETE CONTROL

If the heating control is discrete, then DO4 and DO5 are used to activate
Stage 1 and Stage 2 of heating. DO4 must be wired to Heating Stage 1 and
DO5 must be wired to Heating Stage 2.
Wiring for the Heating Stage 1 is shown in Figure 20. To wire DO4 for
Heating Stage 1:
1. Connect the HOT terminal to one side of the pilot relay's coil.
2. Connect the DO4 terminal to the other side of the pilot relay's coil.
3. Wire the pilot relay's output to the appropriate specifications for the
device.
J3
Figure 20. DO4 - Heating Stage 1 Wiring.
FCU Controller
HOT DO5 DO4 HOT DO3 DO2 HOT
Installation Guide
DO1 AO AGND
ELECTRIC COIL
OR
VALVE
27