Thermo King UT-1200, Manual

Page: 118 / 169

Refrigeration Service Procedures
118
Set Up and Test of Evacuation
Equipment
NOTE: See the previous two pages for the
following discussion.
1. Connect the evacuation system to a 110 Vac
power supply. Connect a gauge manifold and
refrigerant supply to the charging port above
valve V-4. Turn the micron gauge On.
2. Close valves V-1, V-3 and V-4. Valve V-2 is
open.
3. Turn the vacuum pump On.
4. Open valve V-1 to the pump. The micron
gauge needle will move to the left. (See
micron gauge scale diagram—previous page).
NOTE: If the vacuum pump is okay, and
there are no leaks between V-1 and V-3, the
micron gauge should show less than 500
microns. If not, locate and correct the
problem.
5. With the pump still operating, open valve V-3.
If the micron reading does not return to a level
of less than 500 microns, locate and correct
the problem before continuing.
6. With the vacuum pump still operating, open
valve V-4. The micron level will rise
momentarily. If the micron reading does not
return to a level of less than 500 microns,
locate and correct the problem before
continuing.
7. Evacuate hoses to 100 microns or lowest
achievable level below 500 microns.
8. Once 100 microns is reached, close valve V-1
to the pump. Turn the vacuum pump Off.
9. Observe the micron gauge reading. The
vacuum rise should not exceed 2000 microns
in 5 minutes.
10. If the rise is above 2000 microns in 5 minutes,
check all hoses and connections for leaks.
Hoses with moisture present will require
additional evacuation time to achieve
satisfactory results.
NOTE: Dirty vacuum pump oil or a defective
vacuum pump will prevent a low micron
reading. Hoses and fittings can be isolated
individually to identify leaks.
Using Evacuation Mode
NOTE: A Mechanics/Premium HMI Control
Panel is required to access the Evacuation
Mode. On units equipped with the Standard HMI
Control Panel, it must be disconnected and have
a Mechanics HMI Control Panel connected
instead. Refer to the appropriate Microprocessor
Diagnostic Manual for more information. The
following example shows the
Mechanics/Premium HMI Control Panel.
Evacuation Mode opens the ETV (if so equipped)
all the way for refrigeration system evacuation.
1. Start at the Standard Display and press the
MENU key.
Figure 193: Press Menu Key
2. The Maintenance Menu is accessed from the
first Main Menu screen that appears; either the
Language Display or the Alarms Display. The
Alarms Display is shown here. Press and hold
both the Exit key and the unlabeled soft key
for 5 seconds.
Figure 194: Press and Hold Exit and Unlabeled
Keys