Electronic Throttling Valve (Etv) Testing; Electronic Throttling Valve (Etv) Replacement; Removal - Thermo King T-680S Series Maintenance Manual

Refrigeration Service Procedures
Electronic Throttling Valve
(ETV) Testing
The ETV is controlled and monitored by the SR-3
Microprocessor Control System. Alarm Code 89
(Check Electronic Throttling Valve Circuit)
indicates a possible problem with the ETV. Refer
to the appropriate Microprocessor Diagnostic
Manual for information about testing the ETV.
Electronic Throttling Valve
(ETV) Replacement
NOTE: The Old Style ETV is being replaced
with the New Style ETV starting in 09/16. There
are some physical differences, but they are
functionally the same.

Removal

1. Pump down the low side and equalize the
pressure to slightly positive. Make sure to
front seat the suction service valve to isolate
the low side and use the suction access port to
access the low side.
2. The ETV must be open to remove the stepper
motor and piston assembly. Open the ETV by
placing the unit in the Evacuation Mode/Test,
and then turning the unit off. Refer to the
appropriate Microprocessor Diagnostic
Manual for information about the Evacuation
Mode/Test.
3. Old Style ETV - Disconnect the ETV harness
from the four-pin connector on the main wire
harness.
New Style ETV - Disconnect the four-pin
connector on the main wire harness from the
four-pin connector on the ETV.
144
1
2
3
1. Small Hex on Stepper Motor
2. Large Nut
3. Valve Body
Figure 227: Old Style ETV
2
3
1. Four-Pin Connector
2. Stepper Motor
3. Valve Body
Figure 228: New Style ETV
1
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