Section 4 Refrigeration
4-9
Evacuating System
To achieve the required levels of evacuation, a properly
maintained two stage vacuum pump in good condition is
required. It is absolutely essential to maintain your
vacuum pump according to the manufacturer’s
instructions including required oil changes at the
recommended intervals. Vacuum pump oil should always
be changed after evacuating a contaminated system.
Vacuum pump performance should be checked
periodically with a micron gauge.
1. Make certain that charging cylinder valve, hand
shut-off valve, and manifold gauge valves are closed.
2. Start vacuum pump.
3. Open hand shut-off valve and slowly open both
manifold valves, turning counterclockwise, for two
full rotations.
4. Operate vacuum pump for a minimum of 30
minutes to a minimum of 29.9” (500 micron)
vacuum.
5. Close hand shut-off valve to vacuum pump. Watch
compound gauge for several minutes. If reading
rises, there is a leak in the system, go to step 6. If
no leak is indicated, stop vacuum pump. System is
now ready for charging.
6. If a leak is indicated, stop vacuum pump and
introduce a small charge of refrigerant into system
by cracking valve on bottom of charging cylinder
until system is pressurized to 40 or 50 lbs psig.
7. Leak test low-side. Close compound gauge. Run
compressor for a few minutes and leak test
high-side. When leak is found, recapture refrigerant
using EPA approved recovery system. Repair and go
back to step 1.
Charging The System
Preparing The Charging Cylinder:
1. Make certain that hand shut-off valve to vacuum
pump is closed.
2. Close high-side manifold gauge valve.
3. Set charging cylinder scale to pressure indicated on
cylinder pressure gauge.
4. Observe refrigerant level in sight glass. Subtract
amount to be charged into system and note shut off
point.
5. Open charging cylinder valve slowly and allow
proper charge to enter system.
6. As soon as refrigerant in sight glass has gone down
to predetermined level, close charging cylinder valve.
7. Allow system to sit for five minutes.
8. Turn on refrigerator compressor. Run compressor for
a few minutes and monitor system pressures.
9. When satisfied that the unit is operating correctly,
clamp the high-side process tube with the pinch-off
tool while the unit is still running.
Disconnect the charging cylinder heater at this time
to prevent the cylinder pressure from exceeding its
maximum limits.
WARNING
If high vacuum equipment is used, just crack both
manifold valves for a few minutes and then open
slowly for the two full turns counterclockwise. This will
prevent the compressor oil from foaming and being
drawn into the vacuum pump.
CAUTION
Check the serial plate for the correct refrigerant type.
It is extremely important to verify the type of
refrigerant in the system before starting any sealed
system repairs. After charging the system with liquid
be certain to wait at least 5 minutes before starting
the compressor to give the refrigerant a chance to
disperse throughout the system. Otherwise the
compressor could be damaged by attempting to pump
excessive quantities of liquid.
CAUTION
R-134a systems are particularly susceptible to
moisture contamination which can only be prevented
by evacuating the System for a minimum of 30
minutes to attain a minimum 29.9 inch (500 micron
or lower) vacuum.
WARNING
Summary of Contents for FFH17F8HW0
Page 2: ......
Page 14: ...Section 2 Installation Information 2 6 Notes ...
Page 18: ...Section 3 Electronic Control 3 4 Notes ...
Page 33: ...Section 4 Refrigeration 4 15 HFC 134a CFC 12 Pressure Temperature Chart ...
Page 36: ...Section 4 Refrigeration 4 18 Notes ...
Page 48: ...Section 5 Component Teardown 5 12 Notes ...
Page 53: ...Section 7 Wiring Diagram 7 1 ...