Condenser Fan Control - York YCAV0157 Installation Operation & Maintenance

FAN FAN
12 10
SYS
#2
SYS
#1
FAN FAN
11 9
FAN BAFFLES FAN BAFFLES
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.
TABLE 11 - FAN STAGES AND CORRESPONDING OUTPUTS
4 FANS
Stage 1
(1 Fan ON)
Sys 1 Fan 1
Sys 2 Fan 2
Stage 2
(2 Fans ON)
Sys 1 Fans 3 & 5
Sys 2 Fans 4 & 6
Stage 3
(3 Fans ON)
Sys 1 Fans 1, 3, & 5
Sys 2 Fans 2, 4 & 6
-
Sys 1 Fans 3, 5, 7, & 9
Sys 2 Fans 4, 6, 8, & 10
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
JOHNSON CONTROLS
CONDENSOR FAN CONTROL
FAN FAN FAN
8 6 4
FAN FAN FAN
7 5 3
FAN BAFFLES
5 FANS
Stage 1
(1 Fan ON)
Sys 1 Fan 1
Sys 2 Fan 2
Stage 2
(2 Fans ON)
Sys 1 Fans 3 & 5
Sys 2 Fans 4 & 6
Stage 3
(3 Fans ON)
Sys 1 Fans 1, 3, & 5 Sys 1 Fans 1, 3, 5, & 11
Sys 2 Fans 2, 4, & 6 Sys 2 Fans 2, 4, 6, & 12
Stage 4
(4 Fans ON)
Stage 5
(5 Fans ON)
Sys 1 Fans 1, 3, 5, 7, 9, & 11
Sys 2 Fans 2, 4, 6, 8, 10, & 12
FAN
FAN LOCATIONS
2
11 FAN UNITS - OMIT FAN 12
VSD/
10 FAN UNITS - OMIT FANS 11 & 12
CONTROL
9 FAN UNITS - OMIT FANS 10,11 & 12
PANEL
8 FAN UNITS - OMIT FANS 9,10,11 & 12
FAN
1
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 shows the fan staging and the outputs for each
fan stage on 4, 5, and 6 fan systems. The microproces-
sor 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.
6 FANS OUTPUT
Stage 2
(2 Fans ON)
Sys 1 Fans 1 & 11
Sys 2 Fans 2 & 12)
-
Stage 4 1 and 2
(4 Fans ON)
2 and 3
-
Stage 6 1, 2, and 3 Sys 1: 4CR, 5CR, & 6CR
(6 Fans ON)
FORM 201.21-NM1 (1223)
LD10632
CONTACTORS
1 Sys 1: 4CR
Sys 2: 7CR
2 Sys 1: 5CR
Sys 2: 8CR
Sys 1: 4CR & 5CR
Sys 2: 7CR & 8CR
Sys 1: 5CR & 6CR
Sys 2: 8CR & 9CR
Sys 2: 7CR, 8CR, & 9CR
7
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