8–21
62-11637
8.7
REFRIGERANT SYSTEM SERVICE
of refrigerant system equipment, servicing the refriger-
ant charge, leak checking and evacuation. Procedures
for refrigerant system service are provided in the fol-
lowing sub paragraphs.
Figure 8.22 Refrigerant System Service Equipment
8.7.1
Refrigerant System Service Connections
To service the refrigerant system, service equipment is
connected at the compressor discharge service valve,
compressor suction service valve and/or the liquid line
service valve.
When connecting to a valve, backseat the valve (turn
counterclockwise) to close off gauge connection and
attach service line to the valve. Open valve 1/4 to 1/2
turn (clockwise) and then purge the service line. See
for an example of a full service connection
setup.
NOTE
To avoid damage to the earth’s ozone layer, use
a refrigerant recovery system whenever remov-
ing refrigerant from a refrigeration system.
When working with refrigerants you must com-
ply with all local government environmental
laws, U.S.A. EPA section 608.
8.7.2
Servicing the Refrigerant Charge
Servicing of the refrigerant charge includes: checking
the charge level, checking for noncondensibles, remov-
ing the charge, pumping down the low side, pumping
down the compressor, adjusting the charge level and
adding a complete charge. Procedures for charge ser-
vice are provided in the following sub paragraphs.
a. Checking Charge Level
Check the refrigerant charge before adding any refrig-
erant to the system. Only add refrigerant if charge is
low. If charge is low, leak checking must be performed
(Refer to
) and all leaks repaired before
adding refrigerant.
1. Install a manifold gauge set to allow reading of
2. Start unit in Continuous Operation. Adjust set-
point so that unit is running in high speed, fully
loaded and operating in cooling. Run approxi-
mately ten minutes - until the refrigeration system
is warmed up and the refrigerated compartment
temperature is approaching setpoint.
3. Partially block off air flow to condenser coil so
discharge pressure rises to 230 psig (15.7 bar).
4. Check the receiver sight glasses to determine
charge. The system is correctly charged when
the lower sight glass is not empty and the upper
sight glass is not full.
5. If the system appears to be overcharged or
under charged, adjust charge. Refer to following
step f.
b. Checking For Noncondensibles
To check for noncondensibles, proceed as follows:
1. Install a manifold gauge set to allow reading of
suction and discharge pressure. See
2. Stabilize system to equalize pressure between
the suction and discharge side of the system.
The refrigerant system needs to be off for sev-
eral hours.
3. Measure temperature at the copper tubing leav-
ing the condenser (not the subcooler).
4. Record compressor discharge pressure.
5. Determine saturation pressure as it corresponds
to the condenser temperature using the tem-
perature pressure chart,
6. If gauge reading is not close to the calculated
saturation pressure in step 5, noncondensibles
or mixed refrigerants are present.
7. Remove refrigerant. Refer to following step c.
8. Leak check, evacuate and recharge the system.
1. Vacuum Pump
2. Vacuum Indicator
3. Refrigerant Cylinder
4. Refrigerant Recov-
ery Unit
5. Valve
6. Manifold Gauge Set
7. Suction Service
Valve
8. Heat Exchanger
9. Evaporator
10. Evaporator Expan-
sion Valve
11. Compressor Suction
M o d u l a t i o n Va l v e
(CSMV)
12. Subcooler
13. Condenser
14. Receiver
15. Liquid Line Service
Valve
16. Discharge Service
Valve
17. Compressor
Содержание Transicold X4 7300
Страница 21: ...62 11637 1 6 1 3 SAFETY DECALS ...
Страница 22: ...1 7 62 11637 62 03958 ...
Страница 23: ...62 11637 1 8 ...
Страница 24: ...1 9 62 11637 ...
Страница 119: ...62 11637 SECTION 6 MESSAGECENTER PARAGRAPH NUMBER Page 6 1 MESSAGECENTER MESSAGES 6 1 ...
Страница 278: ......