JOHNSON CONTROLS
25
SECTION 2 – SYSTEM OPERATING PROCEDURES
FORM 160.69-O2
ISSUE DATE: 9/30/2020
2
CONDENSER WATER TEMPERATURE
CONTROL
The YORK YD chiller is designed to use less power
by taking advantage of lower than design temperatures
that are naturally produced by cooling towers through-
out the operating year. Exact control of condenser wa-
ter such as a cooling tower bypass, is not necessary
for most installations. The chiller requires only that the
minimum condenser water temperature be no lower
than the value determined by referring to the formula
below:
Min. ECWT = LCWT – C RANGE + 17ºF
Min. ECWT = LCWT – C RANGE + 9.4ºC
where:
ECWT = Entering Condensing Water Tem-
perature
LCWT = Leaving Chilled Water Temperature
C Range = Condensing water temperature
range at the given load condi-
tion.
At start-up, the entering condenser water temperature
may be as much as 25°F (14°C) colder than the stand-
by return chilled water temperature. Cooling tower fan
cycling will normally provide adequate control of the
entering condenser water temperature on most instal-
lations.
OPERATING LOG SHEET
A permanent daily record of system operating condi-
tions (temperatures and pressures) recorded at regular
intervals throughout each 24 hour operating period
should be kept.
The image below shows a log sheet used by techni-
cians for recording test data on chiller systems. Auto-
matic data logging is possible by connecting the op-
tional printer and programming the DATA LOGGER
function.
An accurate record of readings serves as a valuable ref-
erence for operating the system. Readings taken when
a system is newly installed will establish normal condi-
tions with which to compare later readings.
For example, an increase in condenser approach tem-
perature (condenser temperature minus leaving con-
denser water temperature) may be an indication of
dirty condenser tubes.
LD16236
* NOTE:
A pad of 50 log sheets can be ordered from your local Johnson Controls branch by
requesting Form 160.69-MR1.
FIGURE 4 -
LIQUID CHILLER LOG SHEETS
Summary of Contents for YD A
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