Rinnai HD49kWe Installation Manual page 13

Communication cables
Wired water controllers operate at an extra low voltage (12 V DC), which is supplied from the water
heater. A 10 m long communication cable is supplied for connection to the water heater. Only
Rinnai supplied communication cables may be used.
Connecting communication cables to the mini-plug
DO NOT attempt to connect water controller cables to the mini-plug when it is plugged
into the PCB unless the power to the water heater is switched OFF, otherwise damage to
CAUTION
electrical components may occur.
Water controllers are connected to the PCB by a dedicated pre-wired mini-plug.
Standard electrical cable connectors can be used to terminate the water controller wires to those
on the mini-plug. The existing spade connectors, of the communication cables, will need to be
removed prior to termination. Controllers are not polarity sensitive, however to avoid confusion it is
recommended that like coloured wires be terminated together.
Connecting communication cables to the PCB
DO NOT attempt to connect the mini-plug or water controller cables to the water heater unless the
power to the water heater is switched OFF, otherwise damage to electrical components may occur.
1. Isolate the power supply by switching the power point off and removing the water heater plug
from the power socket.
2. Remove the front cover of the appliance.
3. Insert the mini-plug and the connected water controller cables through the cable access at
the base of the appliance. Ensure the cable connectors are located inside the appliance for
protection.
4. Locate the PCB (bottom right of the appliance), and carefully rotate the plastic safety cover out
of the way.
5. Locate the accessory port socket (bottom front of PCB).
6. Plug the mini-plug into the accessory port socket, the plug and socket are keyed so that they
can only be plugged into the one direction).
7. Proceed with the water controller installation and connect the communication cables to the
controllers.
Electrical connectors
(not supplied)
Pre-wired mini-plug
(supplied)
Communications cable
MC-91, MC-601, BC-100V
Communications cable
MC-100V, wireless controller
(refer image on next page)
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