Johnson Controls YVAHP072B31S, Service Manual

Page: 1371 / 1796

Service Manual
3-57
TROUBLESHOOTING
( )
Is LED3 (yellow)
on I.U. PCB ON?
Is LED3 (yellow) on
I.U. PCB flashing more
than once in 10 seconds.
Yes
Yes
Faulty O.U. PCB.
Set it correctly.
Faulty I.U. PCB.
Faulty I.U. PCB.
Check wiring between
outdoor unit and indoor
units or fuse (EF) for
I.U./O.U. PCB.
No
Yes
No
Does Alarm occur with
all indoor units?
Yes
No
Check other indoor units.
No
No
Is LED3 (yellow)
ON even if connector
CN2 on I.U. PCB
is removed?
Yes Yes
Indoor
Unit
Does refrigerant system
No. setting between
O.U. and I.U correspond?
O.U.: DSW4 and RSW1
I.U.: DSW5 and RSW2
Is LED1 (red) on
Change-Over Box
PCB ON?
Is LED3 (green) on
Change-Over Box
PCB ON?
Yes
No No
Check Change-Over
Box wiring.
Check wiring between
outdoor unit and indoor
units.
No
Is LED2 (yellow) on
Change-Over Box PCB
flashing more than
once in 10 seconds?
No
Replace fuse.
Check other
Change-Over Boxes.
Yes
Is the fuse for
Change-Over Box
PCB blown?
Yes
Is voltage between
"L1" and "N" of PCN1
on Change-Over Box
PCB 208 or 230V?
Faulty Change-Over
Box PCB.
No
Change-Over
Box
(In Case
of Heat
Recovery
System)
Yes
Yes
Set it correctly.
No
for wall mounted
Is SW1 of PCB set to “ ”
(Nonpolar Setting)? *2)
O.U. PCB: Outdoor Unit PCB
I.U. PCB:
Indoor Unit PCB