
10 Troubleshooting
Checking procedure for main parts
SMGB0091 rev.2 - 11/2015
278
Electrical circuit
4-way solenoid
valve coil
4-way solenoid
valve coil
Time Chart
Heating operation
Cooling operation
or
Defrost operation
Heating operation
4-way solenoid valve
Coil voltage
is turned ON
Current is continuously
carried while the reversing
valve is ON.
Bistable solenoid operation type (pulse-activated)
Operation Mode: Cooling → Heating
Reversing Valve: OFF → ON
Operation Mode: Cooling → Heating
Reversing Valve: OFF → ON
When current is applied to the reversing valve coil, an
electromagnetic force headed in the same direction as the
magnetic force is generated, and the valve is turned ON by their
attraction. After the valve is turned ON, the plunger position is
kept by magnetic force with no current applied.
When current is applied to the reversing valve coil, an
electromagnetic force headed in the direction opposite to the
magnetic force is generated, and the valve is turned OFF by
their separation force. After the valve is turned OFF, the plunger
position is kept by spring force.
Coil Attractor
Plunger
Plunger position
Coil case
Magnetic
screw
Spring force (separation force)
Electromagnetic force
(Position-keeping force)
Spacer
Magnet
MElectromagnetic
force (Attraction)
When the reversing valve is
turned ON (Current Applied)
After the reversing valve is
turned ON (No Current Applied)
Coil
Attractor
Plunger
Plunger position
Coil case
Magnetic
screw
Electromagnetic force
(separation force)
Spring force (Position-keeping force)
Spacer
Magnet
Magnetic force (Attraction)
When the reversing valve is
turned ON (Current Applied)
After the reversing valve is
turned ON (No Current Applied)