York eco YCAS Series, Manual

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YORK INTERNATIONAL
FORM 201.18-NM9 (602)
8.5 4 COMPRESSOR
CONDENSER FAN CONTROL
The chiller is equipped with 16 or 18 condenser fans,
with 4 or 5 fans per system as given below. Fan control
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 54 or Table 55 depending on
the number of fans/system. There will be a minimum 5
second delay between all fan stages.
Condenser fan ON conditions are governed solely by
the Discharge Pressure (DP). When the DP rises above
220 PSIG, fan stage 1 is activated. From here, subse-
quent fan stages are activated as the DP rises in incre-
ments of 15 PSIG, except stage 6, which is activated
when the DP rises over 290 PSIG. The system will re-
main 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 require-
ments are met. For example, if a system is at a fan stage
of 4, and the DP falls under 195 PSIG and the OAT drops
below 75°F, the fan stage will be reduced to 3. The ON/
OFF conditions are provided 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.
5 / 5 / 4 / 4 Configuration
4 / 4 / 4 / 4 Configuration
FIG. 76 – CONDENSER FAN CONTROL LAYOUT FOR DXST COMPRESSOR UNITS
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