YORK INTERNATIONAL 71
FORM 150.40-NM25
15. If cooling demand drops and the compressor(s)
shutdown, restart cannot occur until the 10 minute
anti-recycle timer times out and a minimum time of
2 minutes passes. This assures a minimum time of
2 minutes 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 pump-
down on start-up routine which eliminates the need
for recycling pumpdown. On start-up of either com-
pressor, the respective system will pumpdown to
approx. 13 lb. (89 kPa) 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.
STANDARD FAN CYCLING
Condenser Fans are cycled by the Micro in response to
outside ambient temperature and Condenser (Dis-
charge) Pressure.
Standard chillers are equipped to operate at ambients
down to 35°F (1.7°C). Below 35°F (1.7°C), a Low Ambi-
ent Kit is required to eliminate nuisance faults (trips).
Fan operation with a Low Ambient Kit is discussed in
the “Options” Section, Page 94. Standard fan operation
and fan placement are shown below.
STANDARD FAN CONTROL
For extreme operating conditions, condenser fan opera-
tion may need to be modified to cycle the fans by dis-
charge pressure only. This should only be changed if
one of the following conditions result in low motor cur-
rent or low suction pressure faults.
1. Discharge pressures run below 140 PSI.
2. Glycol is being utilized and leaving chilled liquid tem-
peratures below 42°F are required.
3. Water is being utilized and leaving chilled liquid tem-
peratures 38°-40° are required.
4. 6 cyl. compressors are running motor currents below
29% when unloaded to 2 cylinders.
The above conditions normally do not cause faulting
however, due to certain environmental conditions, wa-
ter/glycol flow rates and glycol concentrations, this al-
teration may be required.
DUAL CIRCUIT UNITS
CONDENSER FAN LOCATIONS
LD01727
AMBIENT
SYSTEM 1 FANS SYSTEM 2 FANS
TEMP.
Above 65°F Fans E & F ON: 4 sec. Fans C & D ON: 4 sec.
(18.3°C) after compressor start. after compressor start.
*Fans G and H ON: Fans A & B, and D ON:
30 sec. after com- 30 sec. after com-
pressor start. pressor start.
45° (7.2°C) Fans E & F ON: 4 sec. Fans C & D ON: 4 sec.
– 65°F after compressor start. after compressor start.
(18.3°C)
Fans G & H ON: Con- Fans A & B ON: Con-
denser, Press >300 denser, Press >300 PSI
PSI (2067 kPa) (2067 kPa).
OFF: Condenser, Press OFF: Condenser, Press
< 230 PSI (1585 kPA) < 230 PSI (1585 kPa)
35°F (1.7°C) Fans E & F ON: Con- Fans C & D ON: Con-
– 45°C denser, Press >260 denser, Press >260
(7.2°C) PSI 1791 kPa). PSI (1791 kPa).
OFF: Condenser, OFF: Condenser,
Press <190 PSI Press >190 PSI
(1309 kPa) (1309 kPa)
Fans G & H ON: Con- Fans A & B ON: Con-
denser, Press >300 denser, Press >300
PSI (2067 kPa) PSI (2067 kPa)
OFF: Condenser, OFF: Condenser,
Press < 230 PSI Press < 230 PSI
1585 kPa) (1585 kPa)
< 35°F Sys 1 Compressor OFF Sys 2 Compressor OFF
(1.7°C)
*Fan G not present on all chillers. See CONDENSER FAN LOCA-
TIONS (below lefl).
To Next Page
Loading...
