Daikin DPS004 - By-Pass Solenoid Valve; Receiver Solenoid Valve; Indoor Expansion Valve; Outdoor Expansion Valve

By-Pass Solenoid Valve
The By-Pass Solenoid Valve (SVB) is used to “short-circuit”
the high pressure compressor discharge to the low pressure
suction side during start-up. This increases compressor
longevity by minimizing starting torque and inrush current.
Figure 23: By-pass Solenoid Valve
Receiver Solenoid Valve
The Receiver Solenoid Valve (SVR) is used to “bleed off”
refrigerant vapor from the top of the Receiver during pump
down or the transition between mechanical heating and
defrost. Cooling only units will not have this component, only
Heat Pumps .
Figure 24: Receiver Solenoid Valve
Indoor Expansion Valve
The Indoor Expansion Valve (EVI) is a 12 VDC stepper motor
driven valve, used in heating and cooling mode. In cooling
mode EVI is used to expand the refrigerant entering the Indoor
Coil, operating as an evaporator, in much the same way as a
TXV on a conventional air conditioner. In heating mode the EVI
can operate in two different modes, congurable at the keypad.
When congured for Standard during heating mode the EVI
will modulate to fully open and remain in this position. When
congured for heating mode the EVI will modulate to maintain
the Subcooling Set-Point.
Figure 25: Indoor Expansion Valve
Outdoor Expansion Valve
The Outdoor Expansion Valve (EVO) is a 12 VDC stepper
motor driven valve, used in heating and cooling mode. Cooling
only units will not have this component, only Heat Pumps.
In heating mode the EVO is used to expand the refrigerant
entering the Outdoor Coil, which is now and evaporator,
in much the same way as a TXV on a conventional air
conditioner. In Cooling Mode the EVO can operate in two
different modes, congurable at the keypad. When congured
for Standard during Cooling Mode the EVO will modulate
to fully open and remain in this position. When congured
for Cooling Mode the EVO will modulate to maintain the
Subcooling Set-Point.
Short Circuit between
High Pressure Discharge
and Low Pressure Suction
By-Pass
Solenoid
Valve
Vapor Bleed
from top of
Receiver to
Compressor
Suction
Receiver
Solenoid
Valve (EVI)
Indoor
Refrigerant
Temperature
Sensor (IRT)
Indoor
Expansion
Valve (EVI)
IM 1125-7 • REBEL ROOFTOPS 24 www.DaikinApplied.com
refrIgeraTIon sysTeM