Sinclair SCV-EB Series Service Manual page 63

5.19 Hd Troubleshooting
5.19.1 Digital display output
5.19.2 Description
 Hd indicates communication malfunction between master unit and slave unit(Only apply for cascade application)
 Heat pump stops running.
 Error code is displayed on the refrigerant system PCB digital tube and user interface..
5.19.3 Procedure
SW9 DIP switch with wrong settings
More than two units are connected to the wire controller
Power-on interval between master unit and slave unit is
longer than 2min
Wire connection problem
Communication between units is unstable
Address code missing or address code setting duplicate
Replace refrigerant system PCB
Hd
No
No
No
No
No
No
Yes
Check SW9 setting. Master unit: ON; Slave unit: OFF
Make sure there is only one controller connect to
Yes
Make sure power-on interval between master unit
Yes
and slave unit is less than 2min
Reconnect the wire according to the group control
system wiring diagram. Make sure wires are
Yes
connected effectively and no strong electricity or
strong magnetic interference.
Add network matching wire between ports H1 and
Yes
H2 at the terminal of the communication system
Yes
Reset address code by another controller
master unit.
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