181
YORK INTERNATIONAL
FORM 201.18-NM3
8.4
3 COMPRESSOR
CONDENSER FAN CONTROL
The chiller is equipped with 12 or 14 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
operate according to Table 4 or Table 5 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 re-
quirements 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 is controlled
by I/O Expansion Board #2.
TABLE 4 – CONDENSER FAN CONTROL AND FAN CONTACTOR DATA FOR DXST UNITS
WITH 4 FANS/SYSTEM
FIG. 75 – CONDENSER FAN CONTROL LAYOUT FOR DXST COMPRESSORS UNITS
* Newer versions of EPROMs will have ON and OFF pressures 15 PSIG below the published values shown above.
Fan
ON *
OFF *
Fan
Wire
Relay
Stage
Fans
Conditions
Conditions
Contactor
Number
Board
DP
DP & OAT
Output
1
1
>220 PSIG
<150 PSIG & <60°F
9M
130
15
S
2
3
>235 PSIG
<165 PSIG & <65°F
10M
131
14
Y
3
5, 7
>250 PSIG
<180 PSIG & <70°F
11M, 12M
132
10
S
4
1, 5, 7
>265 PSIG
<195 PSIG & <75°F
9M, 11M, 12M
130, 132
10,15
5
3, 5, 7
>280 PSIG
<210 PSIG & <80°F
10M, 11M, 12M
131, 132
10, 14
1
6
1, 3, 5, 7
>290 PSIG
<220 PSIG & <85°F
9M, 10M, 11M, 12M
130, 131, 132
10, 14, 15
1
2
>220 PSIG
<150 PSIG & <60°F
15M
230
15
S
2
4
>235 PSIG
<165 PSIG & <65°F
16M
231
14
Y
3
6, 8
>250 PSIG
<180 PSIG & <70°F
17M, 18M
232
10
S
4
2, 6, 8
>265 PSIG
<195 PSIG & <75°F
15M, 17M, 18M
230, 232
10, 15
5
4, 6, 8
>280 PSIG
<210 PSIG & <80°F
16M, 17M, 18M
231, 232
10, 14
2
6
2, 4, 6, 8
>290 PSIG
<220 PSIG & <85°F
15M, 16M, 17M, 18M
230, 231, 232
10, 14, 15
Fan
ON *
OFF *
Fan
Wire
I/O Expansion
Stage
Fans
Conditions
Conditions
Contactor
Number
Board
DP
DP & OAT
Output TB3
1
13
>220 PSIG
<150 PSIG & <60°F
21M
330
8
S
2
15
>235 PSIG
<165 PSIG & <65°F
22M
331
9
Y
3
17, 19
>250 PSIG
<180 PSIG & <70°F
23M, 24M
332
10
S
4
13, 17, 19
>265 PSIG
<195 PSIG & <75°F
21M, 23M, 24M
330, 332
8, 10
5
15, 17, 19
>280 PSIG
<210 PSIG & <80°F
22M, 23M, 24M
331, 332
9, 10
3
6
13, 15, 17, 19
>290 PSIG
<220 PSIG & <85°F
21M, 22M, 23M, 24M
330, 331, 332
8, 9, 10
LD05022
ç
(Not present on 60 Hz Models.)
8
Summary of Contents for MILLENNIUM YCAS 250
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