Application Data; Location; Water Circuits - York YK Manual

FORM 160.75-EG1 (519)

Application Data

The following section is a user's guide in the application and installation of YK chillers to
ensure the reliable, trouble free life for which this equipment was designed. While this
guide is directed towards normal, water chilling applications, the Johnson Controls sales
representative can provide complete recommendations on other types of applications.

LOCATION

YK chillers are virtually vibration free and may generally be located at any level in a build-
ing where the construction will support the total system operating weight.
The unit site must be a floor, mounting pad or foundation which is level within 1/4" (6.4
mm) and capable of supporting the operating weight of the unit.
Sufficient clearance to permit normal service and maintenance work should be provided
all around and above the unit. Additional space should be provided at one end of the unit
to permit cleaning of evaporator and condenser tubes as required. A doorway or other
properly located opening may be used.
The chiller should be installed in an indoor location where temperatures range from 40°F
to 104°F (4.4°C to 40°C). The dew point temperature in the equipment room must be
below the entering condenser water temperature to prevent condensing water vapor in-
side of the low voltage VSD or low voltage SSS cabinet (if applicable). Applications using
cooling sources other than evaporative or closed loop air exchange methods need to
request a factory-supplied temperature control valve to prevent condensation inside the
VSD or SSS cabinet. Other areas susceptible to water vapor condensate are outside of
the condenser shell and condenser water boxes. Example applications include cooling
condenser water using chilled water, wells, river or other low temperature fluids.
For outdoor applications, contact Large Tonnage Application Team.

WATER CIRCUITS

Flow Rate – For normal water chilling duty, evaporator and condenser flow rates are
permitted at water velocity levels in the heat exchangers tubes of between 3 fps (0.91 m/s)
[3.3 fps (1.0 m/s) for condensers] and 12 fps (3.66 m/s). Two pass units are also limited
to 45 ft H 0 (134 kPa) water pressure drop. The three pass limit is 67.5 ft H 0 (201 kPa).
2 2
Variable flow in the condenser is not recommended, as it generally raises the energy con-
sumption of the system by keeping the condenser pressure high in the chiller. Additionally,
the rate of fouling in the condenser will increase at lower water velocities associated with
variable flow, raising system maintenance costs. Cooling towers typically have narrow
ranges of operation with respect to flow rates, and will be more effective with full design
flow. See Table 6 on page 48 through Table 8 on page 58 for flow limits at design
conditions.
There is increasing interest to use variable primary flow (VPF) systems in large chilled
water plants. VPF systems can offer lower installation and operating costs in many cases,
but do require more sophisticated control and flow monitoring.
JOHNSON CONTROLS 39