United Technologies Carrier TRANSICOLD 68RM35-604-20 Operation And Service page 26

center hose as well as each other. When the low
and high side valves are frontseated (closed), the
high and low side hoses are isolated from each
other and the center hose. It is in the front seated
(closed) position that system pressures can be
monitored. When both
Low Pressure Gauge
Opened
(Backseated)
Hand Valve
Hose Fittings
(0.500-16 Acme)
To Suction Service Port
Low Side Field
Service Coupling
Blue Knob
To service the refrigerant system, the manifold
gauge set is connected to the compressor suction
(low side) service valve
connection and either the compressor discharge
(high side) service valve or the filter drier inlet or
outlet valve for high pressure connection. The high
pressure connection will depend upon the
component to be serviced. (Refer to section 4.)
a. At the Compressor
1. Backseat both suction and discharge service
valves
2. Frontseat manifold set hand valves.
3. Connect low side (blue) manifold hose to the
compressor suction service valve. Open valve
on manifold hose to depress service port
schrader valve.
T-288
valves are open
A
Blue
(Refrigeration
or Evacuation)
Hose
Hose Fitting
with O'Ring
Hose Fitting
(0.500-16 Acme)
A. Connection to
Low Side of System
B. Connection to
High Side of System
Figure 4-2. R-134a Manifold Gauge Set Connections
for low pressure
(backseated), pressure will cause vapor to flow
from the high side to the low side across the
compressor. When only the low side valve is
opened, it is possible to add refrigerant in vapor
form to the system.
High Pressure Gauge
Closed
(Frontseated)
Hand Valve
C B
To Discharge Service or
Manual Liquid Line Port
Red
(Refrigeration
or Evacuation)
Hose
Hose Fitting
with O'Ring
Yellow
(Refrigeration)
Hose
C. Connection to Vacuum
Pump, Refrigerant Cylinder
or Oil Container Purge Line
4. Connect high side (red) manifold hose to the
compressor discharge service valve. Open
valve on manifold hose to depress service port
schrader valve.
5. Midseat both suction and discharge service
valves on compressor to read refrigerant
pressures.
b. At the Compressor Suction Service Valve and
Filter-Drier Inlet or Outlet Valve
1. Backseat both suction and discharge service
valves
2. Frontseat manifold set hand valves.
3. Connect low side (blue) manifold hose to the
compressor suction service valve. Open valve
on manifold hose to depress service port
schrader valve.
4-2
High Side Field
Service Coupling
Red Knob