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SEAT
.47
5/8" HEX
Refrigerant System Pressure Access Ports —
There are two access ports in each circuit - on the suction
tube near the compressor and on the discharge tube near
the compressor. These are brass fittings with black plastic
caps. The hose connection fittings are standard 1/4 SAE
Male Flare couplings.
The brass fittings are two-piece High Flow valves, with a
receptacle base brazed to the tubing and an integral
spring-closed check valve core screwed into the base. (See
Fig. 24.) This check valve is permanently assembled into
this core body and cannot be serviced separately; replace
the entire core body if necessary. Service tools are
available from RCD that allow the replacement of the
check valve core without having to recover the entire
system refrigerant charge. Apply compressor refrigerant
oil to the check valve core's bottom o-ring. Install the
fitting body with 96 +/-10 in-lbs of torque; do not
overtighten.
Compressor Protection
Compressor Overcurrent —
The compressor has internal limbered motor protection.
Compressor Overtemperature Protection (IP) —
The compressor has an internal protector to protect it
against excessively high discharge gas temperatures.
Crankcase Heater —
The heater prevents refrigerant migration and compressor
oil dilution during shutdown whenever compressor is not
operating. The heater is wired to cycle with the
compressor; the heater is off when compressor is running,
and on when compressor is off.
The crankcase heater will operate as long as the power
circuit is energized. The main disconnect must be on to
energize the crankcase heater.
1/2-20 UNF RH
0.596
30°
WASHER
This surface provides a metal to metal seal when
torqued into the seat. Appropriate handling is
required to not scratch or dent the surface.
Fig. 24 - - CoreMax Access Port Assembly
CORE
(Part No. EC39EZ067)
O-RING
1/2" HEX
IMPORTANT: Never open any switch or disconnect
that energizes the crankcase heater unless unit is
being serviced or is to be shut down for a prolonged
period. After a prolonged shutdown on a service job,
energize the crankcase heater for 24 hours before
starting the compressor.
High Pressure Switch —
The system is provided with a high pressure switch
mounted
on
the
discharge
stem-mounted and brazed into the discharge tube. Trip
setting is 630 10 psig (4344 69 kPa) when hot. Reset
is automatic at 505 20 psig (3482 140 kPa).
Loss of Charge Switch —
The system is protected against a loss of charge and low
evaporator coil loading condition by a loss of charge
switch located on the liquid line. The switch is
stem-mounted. Loss of Charge Switch trip setting is 27
psig 3 psig (186 21 kPa). Reset is automatic at 44 5
psig (303 35 kPa).
Outdoor Fan Motor Protection —
The outdoor fan motors are internally protected against
overtemperature.
Control Circuit, 24-V —
The control circuit is protected against overcurrent
conditions by circuit breakers mounted on control
transformer TRAN1 and TRAN2. Reset is manual.
Commercial Defrost Control
The
Commercial
Defrost
coordinates thermostat demands for one stage cooling,
first stage heating, emergency heating and defrost control
with unit operating sequences. See Fig. 26 for board
arrangement.
The DFB is located in the 575J's main control box (see
Fig. 25). All connections are factory-wired. Refer to
Table 9 for details of DFB Inputs and Outputs.
32
45°
DEPRESSOR PER ARI 720
+.01/-.035
FROM FACE OF BODY
7/16-20 UNF RH
C08453
line.
The
switch
is
Control
Board
(DFB)
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