Compressor Condenser Fan Control - York Millennium YCAS Series Installation Operation & Maintenance

8.5 4 COMPRESSOR
CONDENSER FAN CONTROL
The chiller is equipped with 14 or 18 condenser fans,
with 3, 4 or 5 fans per system as given below. Fan con-
trol is via Outside Ambient Temperature (OAT) and Dis-
charge Pressure (DP). There are six stages of fan con-
trol utilizing 3 outputs per system. The fan stages will
work according to Table 2 or Table 3 depending on the
number of fans/system. There will be a minimum 5 sec-
ond delay between all fan stages.
Condenser fan ON conditions are governed solely by
the Discharge Pressure (DP). When the DP rises above
15.2 bar (220 PSIG), fan stage 1 is activated. From here,
subsequent fan stages are activated as the DP rises in
increments of 1.0 bar (15 PSIG), except stage 6, which
is activated when the DP rises over 2.0 bar (290 PSIG).
FIG. 68 – CONDENSER FAN CONTROL LAYOUT FOR DXST COMPRESSORS UNITS
YORK INTERNATIONAL
The system will remain at the highest fan stage reached
unless the OFF conditions given in the next paragraph
are satisfied.
Condenser fan OFF conditions are governed by both
the DP and OAT. Fan staging will be decreased from
the highest stage reached if both the DP and OAT re-
quirements are met. For example, if a system is at a fan
stage of 4, and the DP falls under 13.4 bar (195 PSIG)
and the OAT drops below 23.9°C (75°F), the fan stage
will be reduced to 3. The ON/OFF conditions are pro-
vided in the next two tables.
The tables below also indicate fan contactors, wire num-
bers, and Relay Output Board or I/O Expansion Board
Output numbers relating to fans energized. SYS 1 fan
contactors are controlled by Relay Output Board # 1.
SYS 2 by Relay Output Board # 2. SYS 3 and 4 are
controlled by I/O Expansion Board #2.
FORM 201.18-NM4
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LD05023
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