Indoor Expansion Valve
The Indoor Expansion Valve (EVI) is a 12 VDC stepper motor
driven valve. In cooling mode EVI is used to control the
superheat and expand the refrigerant entering the Indoor Coil,
operating as an evaporator, in much the same way as a TXV
on a conventional air conditioner.
Figure 30: Indoor Expansion Valve
Suction Pressure Transducer
The Suction Pressure Transducer (PTS) is a refrigerant
pressure sensor that screws onto a Schrader fitting on the
suction line of the compressor deck. On single compressor
units (DPS 016–020) this sensor is located on the suction line.
On tandem, two compressor units (DPS 025–028), the PTS is
located upstream of the joint suction.
This sensor is used to ensure that the compressor does not
leave the operating envelope and is used to regulate the super
heat leaving the indoor coil and entering the compressor.
Discharge Pressure Transducer
The Discharge Pressure Transducer (PTD) is a refrigerant
pressure sensor that screws onto a Schrader fitting on
the discharge line of the compressor system. On single
compressor units (DPS 016–020) this sensor is located on the
discharge line. On tandem, two compressor units (DPS 025–
028), the PTD is located downstream of the joint discharge.
This sensor is used to ensure that the compressor does not
leave the operating envelope and is used to regulate the
outdoor fan speed and maintain head pressure.
Discharge Refrigerant Temperature
All Rebel units will have a Discharge Refrigerant Temperature
Sensor (DRT1/DRT3) on the discharge line of each
compressor. This sensor is attached the piping with a metal
clip and wrapped in insulation. The purpose of this device is to
increase compressor life by preventing it from running outside
of the operating envelope.
Suction Refrigerant Temperature
All Rebel units will have a Suction Refrigerant Temperature
Sensor (SRT). This sensor is located on the suction line. Unlike
DRT1 or 3 there is only one SRT for tandem compressor
units. This sensor is used to determine the suction super heat
entering the compressor and is the control input for the EVI in
cooling mode.
Bypass Solenoid
The bypass solenoid (SVB) is used to “short circuit” the high
pressure compressor discharge to the low pressure suction
side during startup. This increases compressor life by reducing
the startup torque and inrush current.
Indoor
Expansion
Valve
Easy
Expansion
Valve
Access
Panel
IM 1125-7 • REBEL ROOFTOPS
28
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Summary of Contents for Rebel DPS003A
Page 109: ...IM 1125 7 109 Addendum follows...
