JOHNSON CONTROLS
20
Form 160.78-N1
Issue date: 2/02/2022
Section 2 - Installation
Evaporator and condenser water piping
The evaporator and condenser liquid heads of chiller
have nozzles which are grooved, suitable for welding
150 psig DWP flanges or the use of flexible couplings.
Factory mounted flanges are optional. If welding is
done on the nozzles, flow switches, condenser level
sensor, and water temperature thermistors should be
disconnected and the welding ground MUST be good
contact located at the head to prevent current damage
to the devices.
The nozzles and water pass arrangements are furnished
in accordance with the job requirements. Refer to the
Product Drawings furnished with the job. Standard
units are designed for 150 psig DWP on the water side.
If job requirements are for greater than 150 psig DWP,
check the unit data plate before applying pressure to
evaporator or condenser to determine if the chiller has
provisions for the required DWP.
Inlet and outlet connections are identified by labels
placed adjacent to each nozzle.
Chilled water
Foreign objects which could lodge in, or block flow
through, the evaporator and condenser tubes must be
kept out of the water circuit. All water piping must be
cleaned or flushed before being connected to the chiller
pumps, or other equipment.
Permanent strainers
, which are supplied by others,
are required in both the evaporator and condenser wa-
ter circuits to protect the chiller and other components
including the pumps, tower spray nozzles, chilled water
coils and controls. The strainer must be installed in the
entering chilled water and condenser liquid line, directly
upstream of the chiller.
Water piping circuits should be arranged so that the
pumps discharge through the chiller, and should be
controlled as necessary to maintain essentially constant
chilled and condenser water flows through the unit at
all load conditions.
If pumps discharge through the chiller, the strainer
may be located upstream from pumps to protect both
pump and chiller. Piping between strainer, pump and
chiller must be very carefully cleaned before start-up.
If pumps are remotely installed from chiller, strainers
should be located directly upstream of the chiller.
Condenser water circuit
For proper operation of the unit, condenser refrigerant
pressure must be maintained above evaporator pressure.
If operating conditions will fulfill this requirement, no at-
tempt should be made to control condenser water temper-
ature by means of automatic valves, cycling of the cool-
ing tower fan, or other means, since chillers are designed
to function satisfactorily and efficiently when condenser
water is allowed to seek its own temperature level at re-
duced loads and off-peak seasons of the year. However, if
it is possible for the entering condenser water temperature
to go below the required minimum, condenser water tem-
perature must be maintained equal to or slightly higher
Figure 8 -
Schematic of a typical piping arrangement
LD08529