M thermal Mono
42
202008
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Procedure
4.4.4
E2
Communication wires X Y E have short
circuited, disconnected or are
misconnected
1
Yes
Reconnect the communication wires
No
Communication wires X Y E are not
connected in a daisy chain
Yes
Connect the communication wires in a
daisy chain
No
Wires between hydronic system main
PCB and electric control box
communication terminals block are loose
Yes
Ensure the wires are connected properly
No
Interference from high voltage (220V or
higher) wires
Yes
Ensure the communication wires and
high voltage wires are separated
No
Communication wires are close to a
source of electromagnetic radiation such
as transformer or strong fluorescent lamp
Yes
Remove the source of interference, or
add additional shielding to the
communication wires
No
Replacing electric control box
communication terminals block resolves
the error
No
Replace hydronic system main PCB
Notes:
1.
Measure the resistance among X, Y
Y and E is infinite.
Communication wiring has polarity. Ensure that the X wire is connected to X terminals and the Y wire is connected to Y terminals.
Midea CAC Confidential
