Greenheck ERCH - Energy Recovery Unit with Packaged DX (468151) - Manual (Page 31)

31
Energy Recovery Unit with Packaged DX
REFRIGERATION SYSTEM
CONDENSER COIL
EV
APOR
AT
OR COIL
COMPRESSOR(S)
HIGH PRESSURE
410 / MANUAL RESET
R22
600 / MANUAL RESET
R410a
8
HGBP
4
25/80 PSI - R22
50/90 PSI - R410a
LOW PRESSURE SWITCH
EQUALIZER LINE
TXV
HEAD PRESSURE
FAN CONTROL
275/210 PSI
R22
425/330 PSI
R410a
9
6
3
5
12
2
1
11
10
7
CONDENSING
FA
N
CHARGING PORT 13
SIGHT GLASS
LIQUID LINE FILTER DRIER
SOLENOID VALVE
SCHRAEDER VALVE
MANUAL VALVE
THERMAL EXPANSION VALVE (TXV)
HOT GAS BYPASS VALVE (HGPB)
SWITCH
13
CHARGING
PORT
Thermostatic Expansion Valve (TXV) - each unit is equipped with a thermal expansion valve . The
valve controls the flow of liquid refrigerant entering the evaporator coil by maintaining a constant,
factory set superheat of 10ºF . The valve is located on the side of the evaporator coil and can be
accessed through the exhaust airstream, through the coil panel access door .
Refrigerant Distributor - attached to the TXV is a refrigerant distributor . The refrigerant distributor
evenly distributes the refrigerant to each circuit of the evaporator coil to provide optimum performance .
Evaporator Coil - each unit contains a single circuit evaporator coil . The coil is located in the outdoor
airstream, directly after the energy wheel . In the DX system, the liquid refrigerant is expanded in the
TXV, and then flows through the evaporator coil . The refrigerant enters the coil as low temp liquid/gas
where it eventually boils into a low temp, low pressure gas prior to going to the compressor . To ensure
proper operation, the coil surface must be cleaned so that air movement over the coil provides the
necessary heat transfer .
Low Limit Pressure Switch - the unit includes a low limit pressure switch (located in the compressor
compartment) . The switch is installed in the suction line and shuts off the DX system when the suction
pressure drops to 25 psi for R22 or 50 psi for R410a . The switch has a built in auto-reset, which will
close the circuit and allow the system to run when the pressure increases back to 80 psi for R22 or
90 psi for R410a .
Compressors - each unit includes 1 or 2 high efficiency scroll type compressors depending on needed
capacity . Scroll type compressors are essentially maintenance free since they are a self-contained, self-
cooling design . The scroll compresses the refrigerant in the gaseous state to a high temperature, high
pressure gas .
Compressor protective devices:
Thermal Overload - each compressor is equipped with an auto reset thermal overload
High Temp Protection - internal devices within the compressor protect it against excessively
high discharge gas temperatures (only on compressors above 6 hp)
Crankcase Heater - Liquid refrigerant is incompressible . Therefore, a crankcase heater
is installed around each compressor in the unit to boil any liquid refrigerant that may
be absorbed into the oil during idle periods . System power energizes the heater; it is
recommended the heater is allowed to run 24 hours prior to compressors being started .
1
2
3
4
5
Factory Installed Refrigeration System Components