Daikin VRV IV+ Service Manual page 360

4 | Third party components
To check the communication between outdoor units
Service manual
360
After checking and correcting possible causes of F1-F2 transmission problems,
perform a communication reset (see
Q1 and Q2 are connection terminals for the transmission wiring between multi
outdoor units.
1 Measure the voltage as shown below:
VDC
Q1
Q2
Q1
Q2
a Terminal Q1
b Terminal Q2
c Connector X37A pin 1
d Connector X37A pin 2
Is the measured voltage correct?
Yes
No
Faulty Waveform.
Possible reasons:
▪ Transmission circuit failure on a PCB.
"4.1.2 Repair
Com.
X37A
X37A
X37A
X37A
c d
Action
Return to the troubleshooting of the
specific error and continue with the
next procedure.
Perform a check of the main PCB, see
"3.11 Main
4
procedures" [ 361]).
Ref.
13 V DC
13 V DC
-3 V DC
-3 V DC
a b
4
PCB" [ 290].
REYQ8~20+REMQ5U7Y1B
VRV IV+ Heat Recovery
ESIE18-15B – 2020.05