Outdoor Unit Valve Functions - Toshiba HFC R407C Service Manual

Valve and sensor function and operation
Outdoor unit - valve functions
Symbol Name of valve
20SF 4-way reversing valve
(4-way valve) Cooling operation
4-way reversing valve
Heating operation
SV1 High-pressure release
solenoid valve
SV2 Hot gas bypass solenoid
valve
SV4 Solenoid valve for D.O.L.
compressor start-up
SV5 Gas balance
SV13 Cooling solenoid valve
SV14 Solenoid valve for
expansion valve.
SV15 Sub heat exchanger
solenoid valve
SV16 Solenoid valve for capillary
SV17 Solenoid valve for compressor Open when compressor ON.
PMV1 Cooling bypass flow
control valve
PMV2 Outdoor flow control valve
66
Outdoor unit
Description of function
OFF: Normal operation.
ON: Low load condition when sub heat exchanger is
required. Used in combination with SV15.
ON: Normal operation.
OFF: Defrost operation.
Heating operation.
Energised when TE >11°C
Opens when Pd < 13 kgf/cm
(For cooling-dominant mode and sub heat exchanger
operation Pd < 17 kgf/cm
Opens when outdoor ThO < 0°C
Opens when the D.O.L. compressor starts for
unloading.
Opens when compressor stops.
Opens for cooling-only operations.
SV14 opens for heating operation.
Opens for sub heat exchanger requirement.
SV16 opens for low load conditions during heating-
dominant operation.
Closed when compressor OFF.
Opens when ThD1 or ThD2 > 110°C.
Opens when ThS > 20°C.
Opens during cooling-dominant operation.
Degree of opening depending on cooling/heating
demands.
2 G (ccoling)
2
G - 3-pipe only).