Carrier 558J Series Service And Maintenance Instructions page 19

Refrigerant System Pressure Access Ports
There are two access ports in the system: 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. See Fig. 16.
The brass fittings are two-piece High Flow valves, with a
receptacle base brazed to the tubing and an integral
TXV SENSOR
BULBS
CIRCUIT 2
DIAPHRAGM
PUSHRODS
FEEDER TUBES
INLET
OUTLET
NEEDLE
VALVE
SPRING
DISTRIBUTOR
Fig. 21 − Thermostatic Expansion Valve (TXV) Operation
Fig. 22 − TXV Sensor Bulb Locations
spring-closed check valve core screwed into the base. 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 over- tighten.
CAPILLARY TUBE
COIL
EXTERNAL EQUALIZER TUBE
CLAMP
TXV SENSOR
BULB
TXV
(CIRCUIT 1)
19
BULB
TXV
SENSOR
BULBS
TXV
(CIRCUIT 2)
CIRCUIT 1
C150325
C12557