T-340
7–2
When the Suction Pressure Valve is frontseated (turned all the way in), the suction (low) pressure can be checked
at the Suction Pressure Gauge.
When the Discharge Pressure Valve is frontseated, the discharge (high) pressure can be checked at the Discharge
Pressure Gauge.
When both valves are backseated (all the way out), high pressure vapor will flow into the low side.
When the Suction Pressure Valve is open and the Discharge Pressure Valve shut, the system can be charged
through the Utility Connection. Oil can also be added to the system.
A R-134a manifold gauge/hose set with self-sealing hoses (see
) is required for service of the models
covered within this manual. The manifold gauge/hose set is available from Carrier Transicold. (Carrier Transicold
part number 07-00294-00, which includes items 1 through 6,
.)
If the manifold gauge/hose set is new or was exposed to the atmosphere, it will need to be evacuated to remove
contaminants and air as follows:
1. Backseat (turn counterclockwise) both field service couplings (see
) and midseat both hand
valves.
2. Connect the yellow hose to a vacuum pump and refrigerant 134a cylinder.
Figure 7.2 R-134a Manifold Gauge/Hose Set
1) RED Refrigeration and/or Evacuation
Hose (SAE J2196/R-134a)
2) Hose Fitting (0.5-16 Acme)
3) YELLOW Refrigeration and / or
Evacuation Hose (SAE J2196/R-134a)
4) Hose Fitting with O-ring (M14 x 1.5)
5) High Side Field Service Coupling (Red
Knob)
6) BLUE Refrigeration and / or Evacuation
Hose (SAE J2196/R-134a)
7) Low Side Field Service Coupling (Blue
Knob)
- - - - -
3. Evacuate to 10 inches of vacuum and then charge with R-134a to a slightly positive pressure of 0.1 kg/ cm
2
(1.0 psig).
4. Frontseat both manifold gauge set valves and disconnect from cylinder. The gauge set is now ready for use.
7.3 Service Connections
The compressor suction, compressor discharge, and the liquid line service valves (see
) are provided with
a double seat and an access valve which enables servicing of the compressor and refrigerant lines.
Turning the valve stem clockwise (all the way forward) will frontseat the valve to close off the line connection and
open a path to the access valve. Turning the stem counterclockwise (all the way out) will backseat the valve to
open the line connection and close off the path to the access valve.
To High Side
Access Valve
To Low Side
Access Valve
