Thermo King SB-210, Manual

Page: 122 / 159

Refrigeration Service Operations
122
Electronic Throttling Valve
(ETV)
Removal
1. Pump down the low side and equalize the
pressure to slightly positive.
2. Remove the evaporator access panels.
3. Remove the clip and disconnect the ETV
harness connector from the stepper motor.
4. Unscrew the large nut that attaches the stepper
motor and piston assembly to the valve body.
The torque on the nut is approximately 100
ft-lb (136 N•m). Hold the valve body with
backup wrench to prevent damage to the
refrigeration tubing.
5. If the complete ETV assembly is being
replaced, unsolder and remove the valve body.
It may be necessary to unsolder the tubes
above or below the valve body to obtain
enough clearance to remove the valve body.
Note the position of the valve body so the new
one will be placed in the same position. The
new ETV could interfere with the evaporator
access panel if it is not placed in the same
position as the old one.
Installation
1. If an ETV service kit (stepper motor and
piston assembly) is being installed, go to
step 2. If a complete ETV assembly is being
installed, proceed as follows:
a. Remove the stepper motor and piston
assembly from the valve body on the new
ETV assembly.
b. Clean the tubes for soldering.
CAUTION: Unscrew the large nut. Do not
unscrew the small nut.
WARNING: If the ETV is stuck in the
closed position, much of the refrigerant
charge may be trapped in the evaporator.
If you hear refrigerant begin to flow
through the valve when the stepper motor
and piston assembly are loosened,
unscrew the stepper motor and piston
assembly no more than four turns and
check the suction (low side) pressure on
the gauge manifold. If the suction
pressure has increased from the pressure
to which it was equalized after the low side
pump down, refrigerant is trapped and
must be recovered. Screw the stepper
motor and piston assembly back into the
valve body. Attach a refrigerant recovery
device to the service port on the receiver
tank outlet valve. Midseat the receiver tank
outlet valve, and recover the refrigerant
charge. The stepper motor and piston
assembly may then be removed.
1. Stepper Motor 4. Large Nut
2. Harness
Connector 5. Valve Body
3. Clip
Figure 108: Electronic Throttling Valve
ARA168
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