Heat Controller Water Source Heat Pump - Manual (Page 27)

WattMaster WHP Section 2
Installation and Wiring 2-3
Communications Loops
The Communications Loop is two wire shielded RS-485. The loop is best connected in
daisy chain configuration, meaning the loop is connected from one controller to another.
It is not necessary to sequentially address the WHP Controllers in relation to their
location on the loop. Cable must be Belden No. 82760 or equivalent.
Tip: Incorrect wiring of the communications loop is the most common mistake made
during installation. Before beginning installation, write down the wire color used
on each terminal connection and consistently maintain that color code. It is
recommended that a continuous wire run be made between devices. Anytime a
splice is made in the cable you increase your chance of problems.
Caution: Make sure when you are inserting wires into the terminal blocks that
strands of wire do not stick out and touch the next terminal. This could
cause a short or erratic operation.