
10 Troubleshooting
Checking procedure for main parts
SMGB0091 rev.2 - 11/2015
277
10
Checking procedure for the reversing valve
Troubleshooting
Is the connector PCN100
*1) on PCB1 connected
correctly?
Is there output voltage
*3) generated from the
connector PCN100 *1) on
PCB1?
Is the resistance of the
reversing valve coil *2)
correct?
Reversing valve is faulty (valve
locking, etc.). Replace it with a
new one.
Yes
No
No
No
Yes
Yes
Connect it correctly.
Reversing valve is faulty
(disconnection, etc.). Replace it
with a new one.
PCB1 is faulty (Faulty reversing
valve circuit, etc.). Replace it
with a new one.
?
N O T E
*1) PCB1 connector PCN100, pin 1 - 3
*2) See in the table “Resistance (Ω)”
*3) See in the table”Output voltage”
according to coil type operation mode.
Output voltage
Reversing valve ON
Reversing valve OFF
?
N O T E
The values may differ depending on testers.
Appropriate output voltage is 70~339VDC
Test lead (+side)
pin 1
pin 3
Test lead (-side)
pin 3
pin 1
Range of voltage
325 VDC
163 VDC
Actions of 4-way solenoid valve
Monostable solenoid operation type
Operation Mode: Heating Reversing Valve Coil: ON
Operation Mode: Cooling Reversing Valve Coil: OFF
Electric Current Applied
Current is applied to the reversing valve coil and so attraction is
generated. The plunger position is kept by the electromagnetic
force.
No Electric Current Applied
No current is applied to the reversing valve coil and so no
attraction is generated. The plunger position is kept by spring
force.
Coil
Attractor
Plunger
Plunger position
Coil case
Magnetic
screw
Spring force
Electromagnetic force
(Position keeping force)
Coil
Attractor
Plunger
Plunger position
Coil case
Spring force
(Position keeping force)
Electromagnetic force = 0
Magnetic
screw