4-3
©
2015 Mobile Climate Control
T-367 Rev. 05/2015
4.4 SUCTION AND DISCHARGE SERVICE VALVES
The suction and discharge service valves (Figure 4-3)
are provided with a double seat and a gauge port,
which allows servicing of the compressor and
refrigerant lines.
Turning the valve stem counterclockwise (all the way
out) will
backseat
the valve to open the line to the
compressor and close off the gauge port. In normal
operation, the valve is backseated to allow full flow
through the valve. The valve should always be
backseated before removing the gauge port cap.
Turning the valve stem clockwise (all the way
forward) will
frontseat
the valve to isolate the
compressor line and open the gauge port.
To measure suction or discharge pressure, midseat
the valve by opening the valve clockwise 1/4 to 1/2
turn. With the valve stem midway between
frontseated and backseated positions, the suction or
discharge gauge port is open to both the compressor
and the line.
SERVICE
PORT (R-22)
VALVE STEM CAP
VALVE
STEM
TO DISCHARGE OR
FROM SUCTION LINE
PORT TO
COMPRESSOR
Service Valve
Frontseated
(clockwise)
Service Valve
Backseated
(counterclockwise)
ACCESS VALVE
(R-134a)
ACCESS VALVE CAP
Figure 4-3 Suction or Discharge Service Valve