44
YORK INTERNATIONAL
A. Timer Operation at Suction Pressures in the
“Control Zone” (Fig. 16)
FIG. 16 – “CONTROL ZONE”
Loading Timer:
This 150 sec. timer counts from 150
sec. to “0” and holds at “0” as long as
suction pressure is within the “Con-
trol Zone”. If at “0” an immediate re-
sponse will take place on a pressure
rise to “Above the Control Zone”.
NOTE: The timer position (time in sec.)
which is present during a pressure
transition from above or below the
“Control Zone” is continued without
interruption. In other words: if the
loading timer is at 40 sec. with pres-
sure above or below the “Control
Zone”, the loading timer will continue
to count down from that point as the
suction pressure level enters the
“Control Zone”. No loading action will
ever take place in the “Control Zone”.
Unloading Timer: This 30 sec. timer counts from 30 sec.
to “0” and holds at “0” as long as suc-
tion pressure is within the “Control
Zone”. If at “0” an immediate unload
response will take place on a suction
pressure drop to “Below the Control
Zone”.
NOTE: The timer position (time in sec.)
which is present during a pressure
transition from above or below the
“Control Zone” to the “Control Zone”
is continued without interruption. In
other words: If the unloading timer is
at 20 sec. with pressure above or be-
low the “Control Zone”, the unloading
timer will continue to count down from
that point as the suction pressure
level enters the “Control Zone”. No
unloading action will ever take place
in the “Control Zone”.
B. Timer Operation at Suction Pressures
“Above the Control Zone” (Fig. 17)
FIG. 17 – “ABOVE THE CONTROL ZONE”
Loading Timer:
This 150 sec. timer constantly cycles
from 150 sec. to “0” and restarts at
“150”. Loading will occur in 150 sec.
intervals whenever the timer counts
down to “0” until the system is com-
pletely loaded.
NOTE: The timer position (time in sec.)
which is present during a suction
pressure rise from the “Control Zone”
to “Above the Control Zone” is con-
tinued without interruption. In other
words: if the loading timer is at 20
sec. in the “Control Zone”, the timer
will continue to count down from that
point on a pressure rise from the
“Control Zone” to “Above the Control
Zone”. After 20 sec., loading will take
place. This still assures a minimum
of 1 minute between stages of load-
ing even if the timer is at “0” when
suction pressure rises to “Above the
Control Zone”.
Unloading Timer: This 30 sec. timer constantly cycles
from 30 sec. to “0”. The timer starts
at 30 sec. whenever the Loading
Timer starts at 150 sec. It then counts
down to “0” and holds at “0” for the
next 120 sec. until the Loading Timer
restarts. No unloading action takes
place while pressure is “Above the
Control Zone”.
NOTE: The timer position (time in sec.)
which is present during a pressure
rise from the “Control Zone” to “Above
the Control Zone” is continued with-
out interruption. In other words: If the
unloading timer is at 20 sec., the timer
will count form that point if pressure
rises form the “Control Zone” to
“Above the Control Zone”. However,
no unloading will take place as long
as pressure stays in the “Above Con-
trol Zone” area.
SUCTION
PRESSURE
PSIG
“BELOW THE CONTROL ZONE”
“ABOVE THE CONTROL ZONE”
“CONTROL ZONE”
SUCTION
PRESSURE
PSIG
“BELOW THE CONTROL ZONE”
“CONTROL ZONE”
“ABOVE THE CONTROL ZONE”
