Specifications

22 YORK INTERNATIONAL
COOLER AND CONDENSER WATER PIPING
YS Chillers have cooler and condenser liquid heads with
nozzles that are grooved for the use of victaulic cou-
plings. The nozzles are alos suitable for welding Class
150 PSIG (1034 kPA) flanges.
The nozzles and water pass arrangements are furnished
in accordance with the job requirements (see Product
Drawing, Form 160.47-PA1). Standard units are designed
for 150 PSIG (1034 kPa) DWP on the water side. If job
requirements are for greater than 150 PSIG (1034 kPa)
DWP, check the unit data plate to determine if the unit
has provisions for the required DWP before applying
pressure to cooler or condenser.
Chilled Water Circuit
The minimum velocity through the tubes is 3 FPS (feet
per second) (0.914 MPS - meters per second), so chilled
water piping designs for variable flow should be selected
with higher velocities at design conditions. The rate of
change should be slow, to make sure that the chiller
controls can track the load.
The following is a guideline for an allowable variable
flow rate of change. This may require modification based
on specific design application.
The maximum allowable rate of change is 15 minutes to
go from 10% to 50% of design flow, based on a mini-
mum chilled water system turnover rate of 15 minutes.
System turnover rate (STR) is a measure of the chilled
water system volume as compared to the design chilled
water flow rate, and is defined as:
Installation
FIG. 9 – SCHEMATIC OF A TYPICAL PIPING ARRANGEMENT
LD03299
System Turnover Rate (STR) =
Volume of chilled water system (gallons)
Design chilled water flow rate (gpm)
As noted previously, if the STR is above 15 minutes,
chilled water flow rate of change is 15 minutes. If STR
goes below 15 minutes, chilled water flow rate of change
must be modified as follows:
Rate of Change from 100% to 50% Flow (minutes) =
15 + 15 – STR
Chilled water must leave the cooler through the con-
nection marked “Liquid Outlet”. Cooling water must en-
ter the condenser through the connection marked “Liq-
uid Inlet”. Refer to Figure 9.
Foreign objects which could lodge in, or block flow
through, the cooler and condenser tubes must be kept
out of the water circuit. All water piping must be cleaned
or flushed before being connected to the unit, pumps, or
other equipment.
Permanent strainers (by others) are required in both the
cooler and condenser water circuits to protect the unit
as well as the pumps, tower spray nozzles, chilled water
coils and controls, etc. The strainer, meeting YORK
specifications should be installed in the entering chilled
water line, directly upstream of the unit.
Water piping circuits should be arranged so that the
pumps discharge through the unit. The circuits should
be controlled as necessary to maintain essentially con-
stant chilled and condenser water flows through the unit
at all load conditions.