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L-2091 Operation
2. Evacuate system per governing EPA regulations.
3. With the manifold gauges still connected to service ports,
attach the center line of gauge set to vacuum pump.
4. Turn on vacuum pump. Open both high and low manifolds
and allow the pump to run so the vacuum reaches 28" Hg.
Close manifold valves and turn off pump.
5. Leave the system for 15 minutes and then observe the
gauge. If any vacuum has been lost, check for leaks,
especially at the quick connect fi ttings or service valves.
6. Repeat vacuum process until a vacuum of 200-400
microns is achieved. If the system has been open to the
environment, allow a minimum evacuation time of 12
hours. Close manifold valves and turn off the pump. If no
vacuum is lost, proceed with charging.
NOTE: If moisture has been a problem, refer to Refrigeration
Bulletin 02-1 for instructions on clean up. This bulletin is avail-
able on the Customer News and Information website under
Technical Field Notices 2002: “Control of Moisture in Refrigera-
tion Systems” (FN#175-I2).
Caution
System contains R-134a refrigerant. Recovery machines
containing mineral based oils should not be used.
Charging the System
Refer to Figure 16 at the back of this manual.
1. Remove line from vacuum pump and connect to a 12 oz
can of R-134a. If using a large R-134a bottle, the charge
must be weighed in.
2. Pressurize the charging lines with refrigerant vapor and
purge.
3. Charging on high side, allow the correct amount of R-134a
to fl ow into the system. On the WAAF033T unit, close high
side service valve (turn fully counterclockwise).
4. Set the constant pressure valve (CPV) or the thermostatic
expansion valve (TXV) if needed.
5. See the Refrigerant Pressure-Temperature Chart, Figure 16.
Setting the CPV
1. Start system and run for 15 minutes. Observe low pres-
sure gauge. The constant pressure valve (CPV) should be
adjusted if required as stated in the section “Installing the
Refrigeration Unit.”
2. Turn valve adjustment knob clockwise (in) to raise pressure
and counterclockwise (out) to lower pressure. Only make
small adjustments to valve, and allow fi ve minutes between
adjustments for the system to equalize.
3. Make sure the valve is dry, and replace cap on constant
pressure valve, being careful not to disturb the setting.
Insulate valve with foam tape. On the WAAF033T unit, top
seat both service valves by turning fully counterclockwise.
4. Remove manifold hoses and replace service port or valve
stem caps tightly.
Factory Settings for CPV
Important
The adjusting knob of the CPV must be covered during opera-
tion. This is to prevent any moisture from getting under the
knob and freezing, which will affect the pressure setting. The
CPV must be insulated airtight.
Adjusting the TXV
On rare occasions, expansion valve adjustments will be neces-
sary but these adjustments are slight—never more than a full
turn.
Use a 5/32" Allen wrench to remove the nut covering the
superheat adjustment valve stem. This exposes the valve
stem. Once the system has had suffi cient running time to
stabilize the frost line, adjustment should be made in 1/4 turn
increments only. Use the 5/32" Allen wrench to make adjust-
ments. After each incremental adjustment, allow 15 to 20
minutes for the expansion valve diaphragm to stabilize. Turning
the valve stem clockwise opens up the valve and increases
the frost line length. Turning the valve stem counterclockwise
closes down the valve and shortens the frost line length. One
full turn equals 4.5°F. Follow directions with the valve. Replace
the outer nut, and tighten to 3 ft-lbs. Insulate valve and bulb
fully. See Figure 16 for TXV factory setting chart.
Model Factory Setting
KRA025
.19 Ton TXV
Turn out completely (CCW) and turn in 7-8
times 360° (CW) 9°F superheat R134a
KRA03
8
.28 Ton TXV
Turn out completely (CCW) and turn in 7-8
times 360° (CW) 9°F superheat R134a
KRA050
.59 Ton TXV
Turn out completely (CCW) and turn in 5-6
times 360° (CW) 9°F superheat R134a
CPV
1 Turn = 5psi, Turn in completely (CW) and
turn out 9-10 times 360° (CCW) 1-3 psi low
side
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