York YCWL0056SE, Installation Operation & Maintenance

Page: 136 / 188

FORM 201.26-NM1
ISSUE DATE: 1/19/2018
SECTION 7 – UNIT CONTROLS
JOHNSON CONTROLS
136
Depending on the option, the trip voltage for a
specific system or unit high current trip can be
programmed. It also calibrates the current read-
out under the OPER DATA key. The approximate
programmed value is calculated using the following
formulas:
System Trip Volts
For individual system high current trip programming
on chillers:
• Add the sum of the compressor and fan RLA’s in
the system
• Multiply the sum by 1.25
• Divide by 225A
• The resulting voltage is the value that should be
programmed
For example, if fan and compressor RLA’s total 100A:
5V x 100A x 1.25 = 625VA
= 2.8V
225A
225A
The programmed value will be 2.8V. A similar calcula-
tion and programming will be necessary for the other
system in a 2-system chiller.
T O T A L N U M B E R O F
C O M P R E S S O R S = 6
The TOTAL NUMBER OF COMPRESSORS is the
total quantity of compressors in the chiller, and deter-
mines the stages of cooling available. Dual system
units may have 4 or 6 compressors.
This MUST be programmed correctly to
assure proper chiller operation.
N U M B E R O F F A N S
P E R S Y S T E M = X
Does not apply to a YCWL chiller.
S Y S X T R I P V O L T S
= X . X V O L T S
U N I T T R I P V O L T S
= X . X V O L T S