Electronic Expansion Valves
CHECKOUT PRCKEDCRE ~
Step 1 - Check EXV Driver Outputs ~ Chcuk l_XV output signals at appropriate terminals on the E.YV driver module (Fig. 8) as folIows:
Connect positive test lcad to terminal 1 on EXV driver. Set meter for approximately 20 vdc. Enter outputs sub-
function of test function by pressing m ‘4 , then
advance to EXVA Open Quick Test by pressing h 5 El
times. Press ENm . The driver should drive the EXV fully iRmIl
open. During the next several seconds connect the nega- tive test lead to pins 2. 3, 4 and 5 in succession. Voltage should rise and fall at each pin. If it remains constant at a voltage or at zero volts, remove the connector to the valve
and recheck. Press 
to reach the EXV A Close Quick
Test. If a problem still exists, replace the EXV driv’er. If the voltage reading is correct, the expansion valve should be checked. Next, text EXVB. Connect the positive test lead to pin 7 and the negative to pin 8,9, IO, 1 
l in succes- sion during the EXVB Quick Test.
Step 2 - Check EXV Wiring ~ Check wiring to elec- tronic expansion valves from terminal strip on EXV driver (Fig. 8).
1.Check color coding and wire connections. Make sure they are connected to correct terminals at driver and EXV plug connections.
12.
EXV A
Fig. 8 - EXV Cable Connections to
EXV Driver Module
2.Check for continuity and tight connection at all pin terminals.
3.Check plug connections at driver and at EXVs. He sure EXV connections are not crossed.
Step 3 ~ Check Resistance of EXV Motor Windings ~ Remove rnBug at 137 terminal strip and check resistance between c’ommon lead (red wire, terminal Uj and remain- ing leads A, B, C. and E (see Fig. 8). Resistance should be 25 ohms
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