MCC 68AC430-100, Руководство по эксплуатации и обслуживанию

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4--2
©
2012 Mobile Climate Control T-353 Rev. 01/2013
When both valves are open (turned
counterclockwise), high pressure vapor will flow into
the low side. When only the low pressure valve is
open, the system can be charged or evacuated.
CAUTION
The AC430 Rooftop Systems has R134a
service port couplings installed on the
unit piping.
4.3.1 Installing R-134a Manifold Gauge/Hose Set
An R-134a manifold gauge/hose set with self-sealing
hoses is pictured in Figure 4-1. The manifold
gauge/hose set is available from Mobile Climate
Control. (Mobile Climate Control P/N 07-00294-00,
which includes items 1 through 6, Figure 4-1). To
perform service using the manifold gauge/hose set,
do the following:
a. Preparing Manifold Gauge/Hose Set for use.
1. If the manifold gauge/hose set is new or was ex
­
posed to the atmosphere it will need to be evacu ­
ated to remove contaminants and air as follows:
2. Back-seat (turn counterclockwise) both field ser ­
vice couplers (see Figure 4-1) and mid-seat both
hand valves.
3. Connect the yellow hose to a vacuum pump and
an R-134a cylinder.
4. Evacuate to 10 inches of vacuum and then charge
with R134a to slightly positive pressure of 1.0
psig.
5. Front-seat both manifold gauge set hand valves
and disconnect from cylinder. The gauge set is
now ready for use.
b. Connecting the Manifold Gauge Gauge/Hose
Set.
To connect the manifold gauge/hose set for reading
pressures, do the following:
1. Connect the field service couplers (see
Figure 4-1) to the high and low in-line service ports.
2. Turn the field service coupling knobs clockwise,
which will open the system to the gauge set.
3. Read the system pressures.
c. Removing the Manifold Gauge Set.
1. While the compressor is still ON, backseat (coun
­
terclockwise) the high side field service coupler on
the manifold gauge set. Mid-seat both hand valves on
the manifold gauge set and allow the pressure in the
manifold gauge set to be drawn down to low side
pressure. This returns any liquid that may be in the
high side hose to the system.
CAUTION
To prevent trapping liquid refrigerant in
the manifold gauge set be sure set is
brought to suction pressure before dis
­
connecting.
2. Back-seat the low side field service coupler and
front-seat both manifold set hand valves. Back ­
seat the in-line system access valves (if applicable).
Remove the couplers from the in-line access
valves.
3. Install both in-line access valve caps.
OPENED
(Backseated )
HAND VALVE
CLOSED
(Frontseated)
HAND VALVE
SUCTION
PRESSURE
GAUGE
DISCHARGE
PRESSURE
GAUGE
To Low Side
Access Valve
To High Side
Access Valve
Red Knob Blue Knob
4.
3.
YELLOW
2.
4.
5. 6.
3.
RED
3.
BLUE
2.
1.
To Refrigerant Tank
or Vacuum Pump
Figure 4-1 Manifold Gauge Set (R-134a)
1. Manifold Gauge Set
2.. Hose Fitting (0.5-16 Acme)
3.. Refrigeration and/or Evacuation Hose
. (SAE J2196/R-134a)
4.. Hose Fitting w/O-ring (M14 x 1.5)
5.. High Side Field Service Coupling
6.. Low Side Field Service Coupling