4-4
©
2012 Mobile Climate Control
T-348 Rev. 07/2012
Opened
(Backseated )
Hand Valve
Closed
(Frontseated)
Hand Valve
To Low Side
Access Valve
To High Side
Access Valve
(Red Knob)
(Blue Knob)
1
4
3
YELLOW
2
4
5
6
3
RED
3
BLUE
2
Low Pressure
Gauge
High Pressure
Gauge
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 Coupler
6. Low Side Field Service Coupler
Figure 4-4 Manifold Gauge Set (R-134a)
4.5 PUMPING THE SYSTEM DOWN OR REMOVING THE
REFRIGERANT CHARGE
NOTE
To avoid damage to the earth's ozone layer,
use a refrigerant recovery system whenever
removing refrigerant.
4.5.1 System Pump Down For Low Side Repair
To service or replace the filter-drier, thermostatic
expansion valve, suction line, liquid line solenoid
valve or evaporator coil, pump the refrigerant to the
condenser and receiver as follows:
a. Install manifold gauge set to compressor discharge
& suction service ports (items 2 & 6). Refer to
Figure 4-6.
b. Frontseat the charge isolation valve (11) by turning
clockwise. Disconnect suction pressure transduc
er (7), install a jumper on the compressor mounted
low pressure switch (8).
c. Start the system and run in cooling. Stop the unit
when suction reaches 2 psig (0.14 Bar).
d. Frontseat the compressor suction service valve (6)
to trap refrigerant in the high side of the system be
tween the compressor suction service valve and
the charge isolation valve. Wait 5 minutes to verify
that system remains at approximately 2 psig (0.14
Bar). If system pressure rises above 2 psig (0.14
Bar), open the compressor suction service valve
and repeat steps c and d until the system remains at
2 psig (0.14 Bar).
e. Service or replace necessary components.
f. Leak check connections and replace filter-drier
(15). Refer to paragraph 4.11.
g. Energize the Liquid Line Solenoid Valve (LSV)
(13) using an external power source (24 VDC).
h. Move the suction service hose (blue) from the
compressor suction service valve to the filter drier
outlet valve (16). Mid-seat the Filter Drier Outlet
Valve and evacuate the low side of the system to
500 microns. Close off the pump valve (23) and
vacuum gauge valve (22) and shut the vacuum
pump off. Wait 5 minutes to verify that vacuum
holds.
i. Back-seat the filter drier outlet valve. Re-attach the
suction service hose (blue) to the compressor suc
tion service valve. Open the suction service valve
(6) and charge isolation valve (11).
j. Disconnect external 24 VDC to liquid solenoid
valve (13).
k. Run and check refrigerant level. Refer to para
graph 4.8.1.
