Valve Override Controls; Suction Modulation Valve; Figure 6-17 Suction Modulation Valve (Smv) - Carrier Streamline Scroll 69NT20-531-300 Operation & Service Manual

under load conditions. The important advantages of a
analyzer are its ability to locate capacitors that have
failed to hold their microfarad ratings, or those that are
breaking down internally during operation. It is also
useful in identifying capacitors when their microfarad
rating marks have become unreadable.

6.19 VALVE OVERRIDE CONTROLS

CAUTION
DO NOT disassemble piston from NEW suc-
tion modulating valve powerhead assembly.
Doing so may result in damage to piston.
Controller function code Cd41 is a configurable code
that allows timed operation of the automatic valves for
troubleshooting. Three test sequences are provided. The
first, capacity mode (CAP), allows alignment of the
unloader and economizer solenoid valves in the
standard, unloaded and
configurations. The second, SMV % Setting (SM)
allows opening of the suction modulating valve to
various percentages and the third, Oil Valve Setting
(OIL) and Liquid Valve Setting (LIV) allows opening or
closing of the oil return solenoid valve and the liquid
injection solenoid valve. A fourth selection is also
provided to enter a time period of up to three minutes,
during which the override(s) are active. If the timer is
active, valve override selections will take place
immediately. If the timer is not active, changes will not
take place for a few seconds after the timer is started.
When the timer times out, override function is
automatically terminated and the valves return to
normal machinery control. To operate the override, do
the following:
a. Press the CODE SELECT key then press an ARROW
key until Cd41 is displayed in the left window. The
right window will display a controller communica-
tions code.
b. Press the ENTER key. The left display will show a
test name alternating with the test setting or time re-
maining. Use an ARROW key to scroll to the desired
test. Press the ENTER key and SELCt will appear in
the left display.
c. Use an ARROW key to scroll to the desired setting,
and then press the ENTER key. Selections available
for each of the tests are provided in the following
table.
d. If the timer is not operating, follow the above proce-
dure to display the timer. Use an ARROW key to
scroll to the desired time interval and press ENTER to
start the timer.
e. The above described sequence may be repeated dur-
ing the timer cycle to change to another override.
economized operating
6-13
Right Display
CAP
(Capacity Mode) ( p y )
SM
(SMV % Setting)
OIL
(Oil Valve Setting) ( g)
LIV
(Liquid Valve Setting, if ( q g,
applicable) li bl )
tIM
(Timer)

6.20 SUCTION MODULATION VALVE

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
10% staging position.
FROM COIL
FROM UNLOADER

Figure 6-17 Suction Modulation Valve (SMV)

Available Selections
AUtO
(Normal Control)
UnLd
(Unloader = Open
Economizer = Closed)
Std
(Unloader = closed
Economizer = closed)
ECOn
(Unloader = closed
Economizer = open)
AUtO
(Normal Control)
0
3
4
6
12
25
50
100
AUto
(Normal Control)
CLOSE
OPEn
AUto
(Normal Control)
CLOSE
OPEn
0 00 (0 minutes/0 Seconds)
In 30 second increments to
3 00 (3 minutes/ 0 seconds)
2-1/8 inch Nut
TO COMPRESSOR
T-309