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FIELD REFRIGERANT ACCESS PORTS
Field service access to refrigerant pressures is through the ac-
cess ports located at the service valves (see Fig. 18-19). These
ports are 1/4 in. SAE Flare couplings with Schrader check
valves and service caps. Use these ports to admit nitrogen to
the field tubing during brazing, to evacuate the tubing and
evaporator coil, to admit initial refrigerant charge into the low-
side of the system and when checking and adjusting the system
refrigerant charge. When service activities are completed, en-
sure the service caps are in place and secure; check for leaks. If
the Schrader check valve must be removed and re-installed,
tighten to 2-3 in.-lb (23-34 N-cm).
OFM1
OFM2
OFM3
Service
Valves
Fig. 18 — 575J*16 Exterior
OFM4
OFM3
Service
Valves
Fig. 19 — 575J*25 Exterior
OUTDOOR COIL METERING DEVICES
The metering devices are multiple fixed-bore devices (Acu-
trol™) swaged into the horizontal outlet tubes from the liquid
header, located at the entrance to each evaporator coil circuit
path. These are non-adjustable. Service requires replacing the
entire liquid header assembly.
To check the indoor coil, disconnect the supply fan signal
(A04-A06 direct-drive fans) or contactor (IFC) coil, then start
the circuit in a Cooling Mode (jumper R to Y1 or Y2) and ob-
serve the frosting pattern on the face of the indoor coil. A frost
pattern should develop uniformly across the face of the indoor
coil starting at each tube at the Acutrol nipple locations.
To check the outdoor coil, disconnect the outdoor fan motor.
Start the circuit in a Heating Mode (jumper R to W1 or W2)
and observe the frost pattern on the face of the outdoor coil.
Failure to develop frost at an outlet tube can indicate a plugged
or a missing orifice.
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. (See Fig. 20-21.) These are brass fittings with
black plastic caps. The hose connection fittings are standard
1/4 in. SAE Male Flare couplings.
The brass fittings are two-piece High Flow valves, with a re-
ceptacle base brazed to the tubing and an integral spring-closed
check valve core screwed into the base. (See Fig. 22.) 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 refrig-
erant oil to the check valve core's bottom o-ring. Install the fit-
ting body with 96 ± 10 in.-lb (1085 ±23 N-cm) of torque; do
not overtighten.
OFM1
OFM2
Circuit
2
LOC
23
Outdoor Coil
High Flow
Access Ports
Defrost
Thermostat
(DFT)
Compressor 2
Fig. 20 — 575J*16 Interior
Outdoor Coil
Defrost
Thermostat
(DFT)
HPS
Circuit 1
LOC
Compressor 1
HPS
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