Table 11 - Fan Stages & Corresponding Outputs - York YCAV0267E Installation Operation & Maintenance

Condenser Fan control on each system is based on dis-
charge pressure. There are up to five possible stages of
fan control utilizing 3 outputs per system. Depending
upon the chiller model, there will be 4,5, or 6 fans per
system. The fan nearest the discharge liquid header
will always be the first fan on a system to start. As fan
stages increment or decrement, a single fan or pair of
fans contained within a pair of fan baffles will be turned
on or off. The diagram above shows the location of
the fan baffles. These baffles will not change location
regardless of the number of fans on a chiller.
The fan control algorithm in the Chiller Control Board
software will not skip steps as fan stages are staged up
and down. The delay between turning on or off fan
stages as discharge pressure rises and falls is 5 seconds.
The controller increments or decrements the fan stage
by one stage based on discharge pressure and fan delay
time.
TABLE 11 - FAN STAGES AND CORRESPONDING OUTPUTS
4 FANS
Stage 1
(1 Fan ON)
Sys 1 Fan 1
Sys 2 Fan 2
Sys 3 Fan 15
Stage 2
(2 Fans ON)
Sys 1 Fans 3 & 5
Sys 2 Fans 4 & 6
Sys 3 Fans 13 & 19
Stage 3
(3 Fans ON)
Sys 1 Fans 1, 3, & 5
Sys 2 Fans 2, 4 & 6
Sys 3 Fans 13, 15, & 19
—
Sys 3 Fans 13, 17, 19 & 21
Stage 4
(4 Fans ON)
Sys 1 Fans 1, 3, 5, & 7 Sys 1 Fans 1, 3, 5, 7, & 9
Sys 2 Fans 2, 4, 6, & 8 Sys 2 Fans 2, 4, 6, 8, & 10
Sys 3 Fans 13, 15, 17 & 19 Sys 3 Fans 13, 15, 17, 19 & 21
JOHNSON CONTROLS
CONDENSOR FAN CONTROL - (CON'T)
3 COMPRESSOR CHILLERS
5 FANS
Stage 1
(1 Fan ON)
Sys 1 Fan 1
Sys 2 Fan 2
Sys 3 Fan 13
Stage 2
(2 Fans ON)
Sys 1 Fans 3 & 5
Sys 2 Fans 4 & 6
Sys 3 Fans 13 & 19
Stage 3
(3 Fans ON)
Sys 1 Fans 1, 3, & 5
Sys 2 Fans 2, 4 & 6
Sys 3 Fans 13, 15 & 19
Stage 4
(4 Fans ON)
Sys 1 Fans 3, 5, 7, & 9
Sys 2 Fans 4, 6, 8, & 10
Stage 5
(5 Fans ON)
Sys 1 Fans 1, 3, 5, 7, 9, & 11
Sys 2 Fans 2, 4, 6, 8, 10, & 12
Sys 3 Fans 13, 15, 17, 19, 21 & 23
TABLE 11 shows the fan staging and the outputs for
each fan stage on 4, 5, and 6 fan systems on both 3 &
4 compressor chillers. The microprocessor fan outputs
and the fan contactors will be the same regardless of the
number of fans. The fan wiring will change to permit
operation of 4, 5, or 6 fans. Fan on and off control points
will vary for standard and optional optimized IPLV chill-
ers. Unless controls dictate all fans running due to high
VSD ambient temperatures, fans will sequence on when
a compressor runs and discharge pressure rises. During
compressor ramp up or ramp down when compressors
are staged, the current fan stage will be held.
The number of fans is factory programmable under the
password protected Unit Setup Mode.
6 FANS
Stage 2
(2 Fans ON)
Sys 1 Fans 1 & 11
Sys 2 Fans 2 & 12
Sys 3 Fans 13 & 15
—
Stage 4
(4 Fans ON)
Sys 1 Fans 1, 3, 5, & 11
Sys 2 Fans 2, 4, 6, & 12
Sys 3 Fans 13, 15,17 & 19
—
Stage 6
(6 Fans ON)
FORM 201.21-NM3 (616)
OUTPUT CONTACTORS
Sys 1: 4CR
1 Sys 2: 7CR
Sys 3: 11 CR
Sys 1: 5CR
2 Sys 2: 8CR
Sys 3: 12 CR
Sys 1: 4CR & 5CR
1 and 2 Sys 2: 7CR & 8CR
Sys 3: 11 CR & 12 CR
Sys 1: 5CR & 6CR
2 and 3 Sys 2: 8CR & 9CR
Sys 3: 12 CR & 13 CR
Sys 1: 4CR, 5CR, & 6CR
1, 2, and 3 Sys 2: 7CR, 8CR, & 9CR
Sys 3: 11CR, 12 CR & 13 CR
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