Midea PTAC Series Service Manual page 29

10.2.3
Drive-by-wire controller failure
Error Code
Malfunction decision
conditions
Supposed causes
Troubleshooting:
Drive-by-wire controller failure
Electric heating and
compressor are on, but 4-way
valve is off
Yes
Check whether the wiring
between controller and dip
switch board is correct
Yes
Wire controller doesn't
match, change the wire
controller
DIP SWITCH TERMINAL
FC(L)
FC(N)
LOW-FAN
HI-FAN
4-WAY
HEAT2
HEAT1
COMP
24V(N)
24V(L)
E
(L )
.
LE
1, Electric heating signal or compressor signal is on, but fan signal is
off
2, Electric heating signal and compressor signal are on, but 4-way
valve signal is off
3, Cooling only models have heating signal, or the 4-way valve signal
and compressor signal are on at the same time.
Wiring mistake
●
wire controller
Faulty
●
Wire controller doesn't match
●
Electric heating or compressor
No
is on, but fan is off
Check whether the wiring
between controller and dip
No
switch board is correct
reconnection
4-way valve is set wrong
DESIGNATION
Front desk control terminal L
Front desk control terminal N
Low fan speed
High fan speed
4-way valve(for heat pump model)
Electrical heater 2
Electrical heater 1
Compressor
24VAC terminal N COM
24VAC terminal L
No
Yes
No
reconnection
Yes
24V CONTROLLER
GL
GH
B
W
(W)
Y
C
R
www.mideaaircon.com 27
Cooling only models have
heating signal, or the 4-way
valve and compressor signal
are on at the same time.
Yes
Wire controller is set wrong