MANIFOLD
The gauges are connected into the air conditioning
systems through a manifold. The manifold has 3 con-
nections (Fig. 1). The low side hose and fitting is con-
nected directly below the low side gauge. The high
side hose and fitting is connected below the high side
gauge.
The center connection of the manifold is used for
recovery and any other necessary service (Fig. 1).
Both the high and low sides of the manifold have
hand shutoff valves. The hand shutoff valves open or
close the respective gauge connections to the center
service connection or to each other (Fig. 1). The man-
ifold is constructed so that pressure will be indicated
on the gauges regardless of the hand valve position.
CONNECTING THE PRESSURE GAUGE AND
MANIFOLD ASSEMBLY
Remove the protective caps from the service valve
gauge ports and valve stems.
Close both of the hand valves on the gauge mani-
fold set.
Connect the compound gauge hose to the compres-
sor suction service valve gauge port (low-side).
Connect the high pressure gauge hose to the dis-
charge service valve gauge port (high-side).
If necessary, to facilitate installation of the gauge
set, loosen the service valve-to-compressor fitting and
rotate the service valve slightly. DO NOT allow the
hose to contact the engine or body components.
Tighten the service valve-to-compressor fitting to 34
NIm (25 ft. lbs.) torque. Tighten the flange-type ser-
vice valve screws to 20 NIm (15 ft. lbs.) torque.
Set both the service valve stems to the mid-position
or the cracked-position. The gauges will indicate
high and low side pressure respectively.Purge any air from the high side test hose by open-
ing the high side hand valve on the manifold for 3 to
5 seconds. The center connection on the manifold
must be open.
Purge any air from the low side test hose by open-
ing the low side hand valve on the manifold for 3 to
5 seconds. The center connection on the manifold
must be open.
The air conditioning system may be operated with
the gauge manifold assembly connected in this man-
ner. The gauges will indicate respective operative
pressures.
SERVICE VALVES
DESCRIPTION
The discharge (high pressure) and inlet (suction)
service valves are used for diagnosis and recovery of
the system. They are also used to isolate the system
during component Removal and Installation.
The service valves are three-position valves (Fig.
2). Normal operating position for the valve stem is
the back-seated (full-out) position. The stem is
turned counterclockwise to place it in this position.
The front seated (full-in) position is used to isolate
the compressor from the system. The stem is turned
clockwise to place it in this position.
Fig. 1 Pressure Gauge and Manifold Assembly Tool
C-3740-B
Fig. 2 Service Valve
JHEATING AND AIR CONDITIONING 24 - 3
AIR CONDITIONING EQUIPMENT
WARNING: EYE PROTECTION MUST BE USED
WHEN SERVICING AN AIR CONDITIONING REFRIG-
ERANT SYSTEM. TURN OFF (ROTATE CLOCKWISE)
ALL VALVES ON THE EQUIPMENT BEING USED
BEFORE PROCEEDING WITH THIS OPERATION.
PERSONNEL INJURY CAN RESULT.
When servicing an air conditioning system, a
R-134a Charging Station and a Recovery/Recycling
Station is required. These devices must meet SAE
standard J2210. Refer to the operating instructions
provided with the equipment for proper operation.
A manifold gauge set (Fig. 1) must also be used
with the Charging and or Recovery/Recycling Station.
The service hoses on the gauge set uses a Quick-Dis-
connect coupler. The coupler has a knob on top which
is used to engage and disengage the sharder valve in
the service port.
MANIFOLD GAUGE SET CONNECTIONS
CAUTION: DO NOT use an R-12 manifold gauge set
on an R-134a system. The refrigerants are not com-
patible and system damage will result.
CENTER GAUGE HOSE
The center hose is YELLOW or WHITE with
BLACK STRIP. It is used to recover, evacuate and
charge the refrigerant system. When the low or high
pressure gauge valves on the manifold gauge set are
opened, the refrigerant in the system will escape
through this hose.
This hose attaches to the Recovery/Recycling sta-
tion. Refer to the Recovery/Recycling station Opera-
tors Manual for proper procedures.
LOW PRESSURE GAUGE HOSE
The low pressure hose is BLUE with BLACK
STRIP. The low pressure port is located on the suc-
tion line.
HIGH PRESSURE GAUGE HOSE
The high pressure hose is RED with BLACK
STRIP. The high pressure port is located on the dis-
charge line.CONNECTION
(1) Remove the service port cap.
(2) Check all valves on the equipment being used
to verify they are closed.
(3) Attach the Quick-Disconnect coupler to the ser-
vice port and turn knob clockwise to depress sharder
valve.
DISCONNECT
(1) Turn coupler knob counter clockwise to release
sharder valve.
(2) Remove the coupler.
(3) Install the service port cap.
Fig. 1 Manifold Gauge Set
4 AIR CONDITIONINGJ
