5407934-UIM-C-1119
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Johnson Controls Ducted Systems
SECTION IV: WIRING COMMUNICATION
All wiring must comply with local electrical codes and ordinances. See
Table 2 for terminal designations.
WIRING REQUIREMENTS
Use standard 18 AWG thermostat wires to connect the communicating
HVAC system and the conventional HVAC system.
Special (shielded) cable is not typically required. As with all communicat-
ing devices, it is a good idea to keep wiring at least 1 ft away from large
inductive loads, for example, electronic air cleaners and motors. If these
wiring practices are ignored, it may introduce electrical interference
(noise), which can cause erratic system operation.
SYSTEM WIRING OVERVIEW
WARNING
If using the thermostat with variable capacity outdoor equipment, DO
NOT connect to the R terminal of the outdoor unit control board.
TABLE 2:
Terminal Designations
Signal
Definition
Label
Data
Non-inverted signal
A (+)
Low-voltage power hot
24 VAC (Hot)
R
Low-voltage power common and data ground
24 VAC (Common)
C
Data
Inverted signal
B (-)
NOTICE
There may be installation applications where large inductive loads
cannot be avoided. In these cases, use shielded wire in proximity to
the inductive loads to ensure proper system functionality.
IMPORTANT:
The communicating system requires four wires to oper-
ate. If installing a communicating system, ensure to supply at least
four wires to each unit/control. For a simple diagram of the ideal wiring
path, see Figure 3.
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