WattMaster Water Source Heat Pump, Installation & Operation Manual

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WattMaster WHP Section 4
4-12 Start-Up and Troubleshooting
3.2.6 Comm Connector - Communications
RS-485 Communications Connector - This connector provides the connection point for
the Local Loop RS-485 communications loop. The wiring consists of a twisted pair of
wires with a shield.
T - RS-485 (+) Communications terminal
SHLD - Common return wire, this point is internally tied to GND on the WHP
Controller.
R - RS-485 (-) Communications terminal
3.2.7 Power Terminal
This connector provides power to the Loop Controller
24 VAC - Connect to the “HOT” side of the control transformer.
GND - The grounded side of the control transformer. If the secondary of the con-
trol transformer is not grounded, you must still observe polarity if the trans-
former powers any other device!
Warning:
Connect only the GND terminal to the grounded side of a transformer
Failure to properly observe polarity will result in damage to the
system. Observe polarity at all points in the system.