YORK INTERNATIONAL
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4. At the end of the 2 minute timer, the 10 minute anti-
recycle timer will start at T = 0. At this time the Micro
Board will check all system conditions. If no safeties
are tripped and cooling demand is present, the lead
compressor will start (unloaded) If a safety is tripped
or no cooling demand is present, the timer will stay
at T = 0 until proper conditions exist. Coincident with
the start of the lead compressor, the associated liq-
uid line solenoid will open after pumpdown is com-
pleted.
5. T = 4 sec. The motor current of the lead compressor
must be > 30% FLA and < 115% FLA. Oil pressure
must be > 10 PSID. If these conditions are not met,
the lead compressor shuts down.
6. T = 30 sec. At this time the oil pressure of the lead
compressor must be a minimum of 25 PSID and suc-
tion pressure must be 80% cutout.
7. T = 60 sec. If cooling demand requires and no safe-
ties are tripped, the lag compressor starts (unloaded)
and its liquid line solenoid opens after pumpdown is
completed.
8. T = 64 sec. The motor current of the lag compressor
must be >30% FLA and <115% FLA. Oil pressure
must be > 10 PSID. If these conditions are not met,
the lag compressor shuts down.
9. T = 90 sec. The oil pressure of the lag compressor
must be a minimum of 25 PSID. Suction pressure of
the lag compressor must be 80% of cutout.
10. T = 2 min. The lead compressor will load if cooling
demand requires.
11. T = 3 min. The lag compressor will load if cooling
demand requires.
12. T = 4 min. The lead compressor’s suction pressure
must be > cutout (cutout = 44 PSIG). At the same
time, the oil pressure of the lead compressor must
be > 20 PSID.
13. T = 5 min. The lag compressor’s suction pressure
must be > cutout (cutout = 44 PSIG). At the same
time, the oil pressure of the lag compressor must be
> 20 PSID.
14. T = 10 min. The anti-recycle timer times out. This
places the timer at T = 0 position. The compressors
will run as long as cooling demand exists.
15. If cooling demand drops and the compressor(s) shut
down, restart cannot occur until the 10 minute anti-
recycle timer times out and a minimum time of 2 min-
utes passes. This assures a minimum time of 2 min-
utes passes between starts, even if a power failure
occurs. At restart, the 10 minute anti-recycle starts
at T = 0.
16.Crankcase Heaters. Any time the compressor(s)
stop, the crankcase heater(s) will be energized.
17.Pumpdown. The system is equipped with a pumpdown
on start-up routine which eliminates the need for re-
cycling pumpdown. On start-up of either compressor,
the respective system will pumpdown to approx. 15
lb. above the suction pressure cutout before the liquid
line solenoid opens. As a result of this, no pumpdown
mode is included in the system switches.
FAN CYCLING
Condenser Fans are normally cycled by the Micro in
response to outside ambient temperature. If the out-
side temp. is above 35°F, COMPR 1 fans E and F and
COMPR 2 fans C and D will come on 4 sec. after the
respective compressor starts. If the outside temp. is
above 55°F, COMPR 1 fans G and H and COMPR 2
fans A and B will come on 30 sec. after the respective
compressor starts.
Fan cycling by temperature can be overridden (at
temperatures below 55°F) by Condenser Pressure. If
the temp. requirements are not met to turn on the fans,
the fans will cycle according to discharge pressure on
the chart below.
(YCHA120, 150, 175 & 200)
FAN LOCATIONS
LD01793
SYSTEM
FAN FANS DISCHARGE PRESSURE TO CYCLE FANS
CONTACTOR CONTROLLED “ON” “OFF”
1 5M E, F 260 LBS. 190 LBS.
1 6M G, H 280 LBS. 210 LBS.
2 7M C, D 260 LBS. 190 LBS.
2 8M A, B 280 LBS. 210 LBS.
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