A.O. Smith CAHP-MC-38 Installation, Operation And Maintenance Instructions page 21

(2) Low voltage cables requirement
There are many communication and signal cables in the hot water system. Please refer to table
5.7 for the detailed requirements on these cables.
Cable Description
The communication cable between
the central controller and the furthest
heat pump unit
The communication cable between
the central controller and the heat
pump unit
Tank temperature sensor cable
Auxiliary heater temperature sensor
cable
Auxiliary heater control cable
Auxiliary heater flow switch cable
Circulation pump control cable
Auxiliary heater pump control cable
Return water solenoid valve or pump
control cable
Table 5.7 Hot Water System Low Voltage Cables Requirement
CAUTION:
Please connect the shielded wire of the communication cable to the ground, this will help to
improve the system anti-interference capability.
(3) Heat pump unit control box layout
Please refer to picture 5.7 for the control box layout of the heat pump unit.
(4) Central controller installation
Standard
Size
Length
2
2*1 mm /
2
2*1 mm /
2
2*1 mm 20m
2
2*1 mm 20m
2
2*1.5mm /
2
2*1.5 mm /
2
1*1.5 mm /
2
1*1.5 mm /
2
1*1.5 mm /
Picture 5.7
Max.
Remarks
Length
200m Shielded cable
100m Shielded cable
100m
100m
100m
Shorted
100m auxiliary heater
storage gas heater
100m
100m
100m
if the
is