York YCWS0313SC, Installation, Operation And Maintenance Manual, Page: 50 / 104

YORK INTERNATIONAL
50
Example:
For ambients above 10°C, the cutout will be activated
(and system shutdown) after 1 minute of compressor
operation if the oil pressure differential is not greater
than 0.7 bar. After 2 minutes it must be greater than 1.4
bar; after 3 minutes, 2 bar; after 4 minutes, 2.7 bar;
and after 5 minutes of operation and onwards, oil pres-
sure must remain higher than 3.4 bar.
For lower ambient temperatures the ramp times are as
follows:
AMBIENT TEMP RAMP TIME
>510°C 5 Minutes
>47°C 6 Minutes
>4°C 7 Minutes
>2°C 8 Minutes
>-1°C 9 Minutes
<=-1°C 10 Minutes
High Oil Temperature Cutout:
This cutout assures oil temperature does not exceed a
safe operating temperature which affects compressor
lubrication. Typical oil temperature during normal op-
eration will be approximately 54 to 66°C.
The cutout will be activated (and system shutdown)
after 2 minutes of compressor operation, when the oil
temperature is above 107°C for more than 3 seconds.
Low Suction Pressure Cutout:
This cutout aids in protecting the evaporator from dam-
age due to ice build up caused by operation at low re-
frigerant charge or restricted refrigerant flow. A num-
ber of transient timer features prevent nuisance trips
during start-up, compressor loading, etc. The cutout is
programmable.
The suction pressure cutout is ignored for the first 45
seconds of operation. During the next 180 seconds of
running, suction pressure may be lower than the cut-
out, but must be greater than:
SUCTION
PRESSURE = PROGRAMMED CUTOUT * (RUN TIME - 25)
CUTOUT 25
This cutout value increases with time until after 225 sec-
onds it equals the programmed cutout value. If suction
pressure falls below the calculated cutout value before
225 seconds of run time, the system will be shutdown.
The following graph shows a typical programmed suc-
tion pressure cutout of 3 bar and its change from time
= 0 sec of compressor run time to 225 seconds of com-
pressor run time.
After 225 seconds of operation with suction pressure
operating above the cutout, a 30 second transient timer
prevents short term fluctuations in suction pressure due
to loading or fan cycling from causing shutdown.
If suction pressure drops below the cutout point after
225 seconds of operation, the transient timer is acti-
vated. While the transient timer is active, suction pres-
sure must not drop below 10% of the cutout initially
programmed and must be greater than:
This transient cutout value increases with time until
after 30 seconds it equals the programmed cutout value.
If the suction pressure falls below the value as calcu-
lated by the formula relative to time, the system will
shutdown on a low suction pressure fault. If the suc-
tion pressure rises above the programmed cutout value,
the 30 second timer will be reset.
When the Dip Switch (S1) on the AMB board is set for
‘Water Cooling’, the cutout is programmable between 3
to 5 bar for both R-22 and R407C models. In this mode,
settings of 3 bar for R-22 and R407C are recommended.
If the switch is set for ‘Brine Cooling’ (glycol) the cut-
out is programmable between 0.3 to 5 bar for both R-
S Y S # H I G H O I L T E M P
S Y S # H I G H O I L T E M P
S Y S # L O W S U C T P R E S S
S Y S # L O W S U C T P R E S S
C.O. = PROGRAMMED C.O. X ( TIME + .1 )
33.3
Micropanel
LD06629
FIG. 15 – SUCTION PRESSURE CUTOUT
7.5
0 30 60 90 120
Run Time (seconds)
Suction Pressure Cutout (barg)
150 180 210 240 270 310
1
1.5
2
2.5
3