Carrier AquaForce 30XV140 Controls, Start-Up, Operation, Service And Troubleshooting Instructions page 54

If the valve is not working properly, continue with the fol-
lowing test procedure:
Check the EXV output signals at appropriate terminals on
SIOB-A (J17-STPR1) and SIOB-B (J17-STPR1). Refer to Ta-
bles 6 and 7 for additional information.
Connect positive test lead to SIOB(X)-J17 terminal 12V for
EXV(X) and SIOB(X)-J18 terminal 12V for economizer
EXV(X). Using the Quick Test procedure on page 116, move the
valve output under test to 100%. DO NOT short meter leads to-
gether or pin 12V to any other pin, as board damage will occur.
During the next several seconds, carefully connect the negative
test lead to pins A,B,C and D in succession. Digital voltmeters
will average this signal and display approximately 6 vdc. If the
output remains at a constant voltage other than 6 vdc or shows 0
volts, remove the connector to the valve and recheck.
Select 0% to close the valve.
NOTE: Twelve vdc is the output from the SIOB board when
the valve is stationary.
If a problem still exists, replace the SIOB board. If the
reading is correct, the expansion valve and EXV wiring
should be checked. Check the EXV connector and intercon-
necting wiring.
1. Check color-coding and wire connections. Make sure
they are connected to the correct terminals at the EXV
board and EXV plug and that the cables are not crossed.
2. Check for continuity and tight connection at all pin
terminals.
Check the resistance of the EXV motor windings. Remove
the EXV module plug SIOB(X)-J17 for main EXV and
SIOB(X)-J18 for economizer EXV. Check the resistance of the
two windings between pins A and C for one winding and pins B
and D for the other winding. The resistance should be 52 ohms
(± 5.2 ohms). Also check pins A-D for any shorts to ground.
Inspecting/Opening Electronic Expansion Valves
IMPORTANT: Obtain replacement gaskets before
opening EXV. Do not re-use gaskets.
To check the physical operation of an EXV, the following
steps should be performed. Charge not isolated within the unit
must be recovered using proper refrigerant recovery techniques.
1. Isolate refrigerant within the chiller and recover re-
maining charge. This will allow access to internal
EXV components. Closing the valves will minimize
the amount of refrigerant that will need to be removed.
For units without isolation valve option: Close the liquid
line ball valve directly above the filter drier as well as the
discharge line ball valves (see the Actuated Ball Valve
section on page 47 for instructions). Remove any remain-
ing refrigerant from the system low side using proper re-
covery techniques. The evaporator liquid line inlet has an
access port that can be used to remove charge from the
evaporator. The economizer assembly has a
connection which can be used to remove charge from the
inlet of the EXVs. Turn off the line voltage power supply
to the compressors.
Table 35 — Color Indicators when Moisture is Present in Refrigerant
COLOR INDICATOR
Green — Dry
Yellow-green — Caution
Yellow — Wet
For units with isolation valve option: Close the ball
valves on the liquid line directly above the filter drier, af-
ter the main EXV before the evaporator, and on the econ-
omizer line to the compressor. Remove any remaining re-
frigerant from the economizer assembly using proper re-
covery techniques. The economizer assembly has a
access connection which can be used to remove charge
from the inlet of the EXVs. Turn off the line voltage pow-
er supply to the compressors.
Ensure refrigerant is removed from both the inlet and outlet
of EXV assemblies. Equipment damage could result.
2. The expansion valve motor is hermetically sealed inside
the top portion of the valve. See Fig. 48. Disconnect the
EXV plug. Carefully unscrew the motor portion from the
body of the valve. The EXV operator will come out with
the motor portion of the device. Reconnect the EXV plug.
3. Enter the appropriate EXV test step under the Test mode
(Main Menu  Quick Test Table). Locate the desired pa-
rameter for the Main EXVs: Circuit A EXV Position,
Circuit B EXV Position or Economizer EXVs: EXV Eco
Position Cir A, EXV Eco Position Cir B. Change the po-
sition to 100%. Observe the operation of the lead screw.
See Fig. 48. The motor should be turning, raising the op-
erator closer to the motor. Motor actuator movement
should be smooth and uniform from fully closed to fully
open position. Select 0% and check open to closed opera-
tion. If the valve is properly connected to the processor
and receiving correct signals, yet does not operate as de-
scribed above, the sealed motor portion of the valve
should be replaced.
Installing EXV Motor
IMPORTANT: Obtain replacement gasket before open-
ing EXV. Do not re-use gaskets.
If re-installing the motor, be sure to use a new gasket in the
assembly. See Fig. 49. It is easier to install the motor assembly
with the piston in the fully closed position. Insert the motor into
the body of the EXV. Tighten the motor to the body to 36 ft-lb
(50 N-m) and then tighten the valve another 30 degrees.
Moisture Liquid Indicator — Clear flow of liquid refrigerant
indicates sufficient charge in system. Bubbles in the sight glass
indicate undercharged system or presence of noncondensables.
Moisture in system, measured in parts per million (ppm),
changes color of indicator. See Table 35. Change filter drier at
first sign of moisture in system.
IMPORTANT: Unit must be in operation at least 12 hours
before moisture indicator can give an accurate reading.
With unit running, indicating element must be in con-
1 / -in. access
tact with liquid refrigerant to give true reading.
4
R-134a, 75 F (24 C) (ppm)
< 30
30-100
>100
54
CAUTION
R-134a, 125 F (52 C) (ppm)
< 45
45-170
>170
1 / -in.
4