• The building must have adequate structural support at the spring isolator locations. The spring
isolators are located directly under the side and end base rails of the chiller. Johnson Controls
do not supply the structural support.
Seismic applications
Avoid installing chillers on springs or roofs where earthquakes are a risk. Springs and roofs
amplify earthquake forces. In earthquake zones, rigidly mount the chillers to ground level concrete
pads. Contact Johnson Controls equipment specialists for help with projects that have seismic
requirements.
Other considerations
Any ductwork or attenuators fitted to the unit must not have a total static pressure resistance at
full air flow that exceeds the capability of the fans installed on the unit. The condenser fans are
propeller-type and are not recommended for use with ductwork, filters, or other impediments to
airflow in the condenser airstream.
When it is required to surround the units in addition to whatever optional louver package is
selected, make sure that the screening can pass the required chiller cfm without exceeding 0.1 in.
wg (24.9084 Pa) external static pressure.
CAUTION
The clearance dimensions provided in
Figure 31
are necessary to maintain good airflow and ensure
correct unit operation. It is also necessary to consider access requirements for safe operation and
maintenance of the unit and power and control panels. Local health and safety regulations, or practical
considerations for service replacement of large components, may require larger clearances than those
recommended.
Clearance requirements
Install the unit with adequate clearances around the units to ensure unrestricted airflow for the
air-cooled condenser coils and to prevent recirculation of warm discharge air back onto the coils.
If these clearances are not maintained, airflow restriction or recirculation causes a loss of unit
performance, an increase in power consumption, and can cause the unit to malfunction. Also
consider the possibility of downdrafts, caused by adjacent buildings, which can cause recirculation
or uneven unit airflow.
Restricted airflow or hot air recirculation can diminish performance, as outlined in
Form 150.12-
AD2, Air-Cooled Chiller Derating Due to Airflow Restrictions
. Johnson Controls unit controls optimize
the operation without nuisance high pressure safety cutouts. However, the system designer must
consider the potential for performance degradation.
For locations where significant crosswinds are expected, such as exposed rooftops, use an
enclosure of solid or louver type to prevent wind turbulence interfering with the unit airflow.
When units are installed in an enclosure, the enclosure height must not exceed the height of the
unit on more than one side. If the enclosure is of louvered construction, the same requirement of
static pressure loss applies as for ducts and attenuators. See
Other considerations
.
25
YVAM Air-Cooled Centrifugal Liquid Chiller
