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8.4
CONDENSER FAN CONTROL
The chiller is equipped with 8 or 10 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 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, Stage 1 is activated. From here, subsequent
fan stages are activated as the DP rises in increments of
1 bar, except stage 6, which is activated when the DP
rises over 20 bar. The system will remain at the highest
Fan
Fans
Stage
1
1
S
2
3
Y
3
5, 7
S
4
1, 5, 7
5
3, 5, 7
1
6
1, 3, 5, 7
1
2
S
2
4
Y
3
6, 8
S
4
2, 6, 8
5
4, 6, 8
2
6
2, 4, 6, 8
TABLE 2 – CONDENSER FAN CONTROL & FAN CONTACTOR DATA FOR DXST UNITS WITH 4 FANS/SYSTEM
Fan
Fans
Stage
1
1
S
2
3, 5
Y
3
7, 9
S
4
1, 7, 9
5
3, 5, 7, 9
1
6
1, 3, 5, 7, 9
1
2
S
2
4, 6
Y
3
8, 10
S
4
2, 8, 10
5
4, 6, 8, 10
2
6
2, 4, 6, 8, 10
TABLE 3 – CONDENSER FAN CONTROL & FAN CONTACTOR DATA FOR DXST UNITS WITH 5 FANS/SYSTEM
FIG. 52 – CONDENSER FAN LAYOUT FOR DXST 2-COMPRESSOR UNITS
144
ON
OFF
Conditions
Conditions
DP
DP & OAT
>15.2 BAR
<10.3 BAR & <15.6°C
>16.2 BAR
<11.4 BAR & <18.3°C
>17.2 BAR
<12.4 BAR & <21.1°C
>18.3 BAR
<13.4 BAR & <23.9°C
>19.3 BAR
<14.5 BAR & <26.7°C
>20.0 BAR
<15.2 BAR & <29.4°C
>15.2 BAR
<10.3 BAR & <15.6°C
>16.2 BAR
<11.4 BAR & <18.3°C
>17.2 BAR
<12.4 BAR & <21.1°C
>18.3 BAR
<13.4 BAR & <23.9°C
>19.3 BAR
<14.5 BAR & <26.7°C
>20.0 BAR
<15.2 BAR & <29.4°C
ON
OFF
Conditions
Conditions
DP
DP & OAT
>15.2 BAR
<10.3 BAR & <15.6°C
>16.2 BAR
<11.4 BAR & <18.3°C
>17.2 BAR
<12.4 BAR & <21.1°C
>18.3 BAR
<13.4 BAR & <23.9°C
>19.3 BAR
<14.5 BAR & <26.7°C
>20.0 BAR
<15.2 BAR & <29.4°C
>15.2 BAR
<10.3 BAR & <15.6°C
>16.2 BAR
<11.4 BAR & <18.3°C
>17.2 BAR
<12.4 BAR & <21.1°C
>18.3 BAR
<13.4 BAR & <23.9°C
>19.3 BAR
<14.5 BAR & <26.7°C
>20.0 BAR
<15.2 BAR & <29.4ºC
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 and the OAT
drops below 23.9°C, the fan stage will be reduced to 3.
The OFF conditions are given in the next two tables.
The tables on the next page also present fan contactor
data for the fans involved in each fan stage. SYS 1 uses
relay board #1. SYS 2 uses relay board #2.
YCAS 0425, 0475, 0515, 0555, 0575 and 0605 models
have 4 condenser fans/system:
Fan
Contactor
9M
10M
11M, 12M
9M, 11M, 12M
10M, 11M, 12M
9M, 10M, 11M, 12M
15M
16M
17M, 18M
15M, 17M, 18M
16M, 17M, 18M
15M, 16M, 17M, 18M
Fan
Contactor
9M
10M, 11M
12M, 13M
9M, 12M, 13M
10M, 11M, 12M, 13M
9M, 10M, 11M, 12M, 13M
15M
16M, 17M
18M, 19M
15M, 18M, 19M
16M, 17M, 18M, 19M
15M, 16M, 17M, 18M, 19M
Relay
Wire
Board
Number
Output
130
15
131
14
132
10
130, 132
10,15
131, 132
10, 14
130, 131, 132
10, 14, 15
230
15
231
14
232
10
230, 232
10,15
231, 232
10, 14
230, 231, 232
10, 14, 15
Relay
Wire
Board
Number
Output
130
15
131
14
132
10
130, 132
10,15
131, 132
10, 14
130, 131, 132
10, 14, 15
230
15
231
14
232
10
230, 232
10,15
231, 232
10, 14
230, 231, 232
10, 14, 15
LD06969
YORK INTERNATIONAL
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