Service manual

6-23
T-294-01
d. Cutonereplacementsensorwireback25.4mm(1.0
inch). (See Figure 6-25.)
e. Strip back insulation on all wiring 6.35mm (1/4
inch).
Sensor
25.4 mm (1.0 inch)
6.35mm (1/4 inch)
Mounting Stud
Figure 6-25. Sensor (AMBS or DTS)
f. Slide two small pieces of heat shrink tubing over
each wire before adding crimp fittings as shown in
Figure 6-26.
g. Slip crimp fittings over dressed wires. Make sure
wires are pushed into crimp fittings as far as
possible and crimp with crimping tool.
h. Solder spliced wires with a 60% tin and 40% lead
Rosincore solder.
i. Slide heat shrink tubing over splice so that both
endsoftubingcoverbothendsofcrimpasshownin
Figure 6-26.
Sensor
Heat Shrink
Tubing (2)
Crimp Fitting
Crimp Fitting
Figure 6- 2 6. Se nsor a nd Wir e Ass embly (AMB S or
DTS)
j. Heattubing,preferablywithaflamelessheatgun.If
not available, a propane torch will work (caution
shouldbetakennottoburntheheatshrinktubingor
wire insulation). Make sure all seams are sealed
tightly against t he wiring to prevent moisture
seepage.
CAUTION
Do not allow moisture to enter wire splice
area as this may affectthe sensor resistance.
k. Securesensortounitandchecksensorresistanceas
detailed in section 6. 23.4.
NOTE
The DTS sensor must have “Presstite”
insulating material placed completely over the
sensor to insure proper function of the sensor.
6.24STEPPER MOTOR SUCTION MODULATION
VALVE (SMV)
On start up of the unit, the valve will reset to a known
open position. This is accomplished by assuming the
valve was fully open, driving it fully closed, resetting
the percentage open to zero, then opening to a known
21%stagingposition.Thismakestheunitreadytostart
and normal operation will begin.
2-1/8 inch Nut
2
1
1. Stepper Motor Suction Modulation Valve (SMV)
2. Drive Module (SD)
Figure 6-27. Stepper Motor Suction Modulation
Valve (SMV)
a. Pre-Check procedure
1. Check unit for abnormal operation.
2. Checkcharge.Ifrefrigerantislowrepairasrequired
and again check operation.
3. Ifsufficientcapacitycannotbemaintainedorunitis
trippingexcessivelyonhighpressureswitch(HPS )
in high ambients, check coil and clean if required.
If capacity or control cannot be maintained turn unit
OFF, then back ON. This will reset the valve i n the
eventthecontrollerlost communicationwiththevalve,
and may correct the problem.
NOTE
Carefully listen to the valve. During reset, the
valve will make a ratcheting noise that may be
heard or felt (this depends upon background
noise)as it is attemptingto close. Ifthis canbe
heard orfelt, it indicatesthat thecontrollerand
drivemodule areattemptingto close thevalve,
and m ay serve as a quick indication that the
drive module is in working order.
During the first few minutes of unit operation,
compressorreliabilityenhancement logic(CREL) may