124
EXV TROUBLESHOOTING — If it appears that the main
EXV or economizer EXV is not properly controlled, perform
the following checks. Through Controls Test move the EXV
fully open. The actuator should be felt through the EXV body.
Then close the valve fully. The actuator should knock when it
reaches the bottom of its stroke.
If the valve is not operating properly, continue checking the
PD4 EXV DIP switch settings (Fig. 64). Check the EXV out-
put signals at J2A and J2B respectively on the EXV module.
Connect positive test lead to J2A or J2B (as appropriate) termi-
nal 5 and move the valve output using the Controls Test to
100%, while being careful not to short any pins as board dam-
age will occur. During the next several seconds (while moving
the actuator) carefully connect the negative test to pins 1, 2, 3
and 4 in succession. The digital voltmeter will average this sig-
nal 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. If confirmed, this may in-
dicate a bad EXV board. Note that 12 vdc is the output from
the EXV board when the valve is stationary.
If the reading is correct, the expansion valve and EXV wir-
ing should be checked. Check the EXV connector and inter-
connecting wiring by double checking color-coding and make
sure that all are connected to the correct terminals and that
wires are not crossed. Check for continuity and tight connec-
tions at all pin terminals.
Disassembling and Assembling the EXV
— Disassemble
the EXV to check EXV motor windings and the condenser liq-
uid level sensor. When disassembling the EXV, always have a
new o-ring available. Do not use the existing o-ring. Place the
piston in the fully open position to disassembly the EXV. When
assembling the VFD, it is easier to install the motor assembly
with the piston in the fully closed position. See Fig. 23 for
EXV cross-section diagrams. See Figs. 66 and 67 for disassem-
bly and assembly instructions.
J7
LIQUID LEVEL
SENSOR
J8
EXV
COMMUNICATION
J9
CCM
COMMUNICATION
GREEN LED
RED LED
DIP SWITCH
SETTINGS
J1
24 VAC
a23-1722
ON
1 2 3 4 5 6 7 8
JUMPER
Fig. 65 — PD4 AUX1 Board (P Compressor Only)
1
1
/
16
in. (27 mm)
a23-1723
Fig. 66 — EXV Disassembly
516
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