3.12 System Evacuation
A properly maintained two stage vacuum pump is required to achieve the minimum requirements of a
good vacuum. The vacuum pump oil should be changed at regular scheduled periods to insure proper
operation. It is mandatory to change oil every time a contaminated system is serviced.
3.12.1 Evacuating the Refrigerant
1)
Make sure that power is disconnected from the unit.
2) Install process valves or adaptors if not already completed.
3) Attach manifold gauges.
4) Low side to suction process.
5) High side to filter / drier process.
6) Center port of manifold hose before hand shut-off valve to charging cylinder.
7) Center port of manifold hose after hand shut-off valve to vacuum pump.
8) Make sure that the charging cylinder valve, hand shut-off valve, and manifold gauges are closed.
9) Start vacuum pump.
10) Open the high side manifold valve first.
11) After a couple of minutes slowly open the low side manifold valve.
12) Operate the vacuum pump for a minimum of 30 minutes or 29.9 inches (50 microns).
13) Close the hand shut-off valve to the vacuum pump and watch the low side manifold gauge for a few
minutes. If there is no change in the gauge pressure the system is sealed and no leaks are present.
At this time the system is ready to charge.
If the vacuum pump can not achieve a good vacuum in a reasonable amount of time, or the low side
gauge looses its vacuum (step 8 above) a leak is present.
At this time add a small amount of charge into the system and check for leaks.
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 INCHES (50 MICRON) VACUUM
Care should be taken when evacuating a system. It is possible with today’s
equipment to draw oil from the compressor thru the low side if both the high
and low side manifold valves are opened initially. To prevent this, start the
vacuum with only the high side open. The low side manifold valve can slowly
be opened after a couple minutes of high side operation.
19
2010 - Viking Preferred Service
SMR-0005
Summary of Contents for DFUW244CL
Page 6: ...Section 1 Introduction to Dual Zone 2010 Viking Preferred Service SMR 0005 ...
Page 10: ...Section 2 Dual Zone Characteristics 2010 Viking Preferred Service SMR 0005 ...
Page 16: ...Section 3 Refrigeration Systems 2010 Viking Preferred Service SMR 0005 ...
Page 27: ...Section 4 TruProtect Control Diagnostics 2010 Viking Preferred Service SMR 0005 ...
Page 30: ...Section 5 Mechanical System Components 2010 Viking Preferred Service SMR 0005 ...
Page 38: ...Section 6 Structural Components 2010 Viking Preferred Service SMR 0005 ...
Page 42: ...Section 7 Electrical Components 2010 Viking Preferred Service SMR 0005 ...
Page 50: ...Section 8 Control Components 2010 Viking Preferred Service SMR 0005 ...
Page 54: ...Section 9 Wiring 2010 Viking Preferred Service SMR 0005 ...
Page 57: ...52 J110 J111 J112 J2 J1 J4 J7 J3 9 3 Main Power Board 2010 Viking Preferred Service SMR 0005 ...
Page 58: ...9 4 User Interface 53 2010 Viking Preferred Service SMR 0005 ...
Page 59: ...Section 10 Reference Charts 2010 Viking Preferred Service SMR 0005 ...
Page 64: ...Section 11 Trouble Shooting Guide 2010 Viking Preferred Service SMR 0005 ...
Page 68: ...Section 12 Reference Photos 2010 Viking Preferred Service SMR 0005 ...
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