Application Data - Carrier Aquasnap 30RAP070 Product Data

Application data

Chiller location and clearances
Do not locate near sound sensitive areas without proper
acoustic consideration. For applications requiring mount-
ing a chiller on a building rooftop, consideration should be
given to using rubber-in-shear or spring isolators to mini-
mize structure-borne transmission. Unit must be level when
installed to ensure proper oil return to the compressors.
Clearances must be provided around chillers for airflow,
service and local code requirements. See dimensional
drawings for specific unit clearance requirements. Ensure
adequate clearance between
maintained.
For 30RAP010-060: When parallel chillers are aligned
such that coils face each other, a minimum of 6 ft
(1829 mm) is recommended. When the parallel arrange-
ment has only one coil drawing air from the space between
chillers, a minimum of 3.5 ft (1067 mm) is recommended.
When parallel chillers have no coils facing each other (a
back-to-back arrangement), be sure to maintain the larger
of the recommended service clearances associated with
each chiller (see the certified drawings). Due to NEC
(National Electric Code, U.S.A.) regulations, a minimum
clearance of 4 ft (1219 mm) must be maintained on the
side of the chiller that has an electrical box. Chiller fan dis-
charge must be at least as high as adjacent solid walls.
Installation in pits is not recommended.
30RAP010-060 MULTIPLE UNIT SEPARATION
a30-4873
6 ft
(1.8 m)
MINIMUM*
* Minimum for when coils face each other. Less clearance is required
in other configurations.
† Clearance of 3.5 ft is required when a coil faces the wall. When
there is no coil facing the wall, see the certified drawing for the
required service clearance.
30RAP070-090 MULTIPLE UNIT SEPARATION
a30-4904
10 ft
(3 m)
MINIMUM
For 30RAP070-090: When chillers are arranged in par-
allel, a minimum of 10 ft (3048 mm) between chillers is
recommended. Acceptable clearance on the cooler con-
nection side or end opposite the control box of the unit
can be reduced to 3 ft (1 m) without sacrificing perfor-
mance as long as the remaining three sides are
adjacent chillers is
3.5 ft (1.1 m)
MINIMUM†
6 ft (1.8 m)
MINIMUM
unrestricted. Acceptable clearance on the side with a con-
trol box can be reduced to 4 ft (1.3 m) due to NEC
(National Electric Code) regulations, without sacrificing
performance as long as the remaining three sides are
unrestricted. Clearances between chillers in dual chiller
applications may be reduced to 6 ft (1.8 m) without sacri-
ficing performance provided the remaining sides are unre-
stricted. For acceptable clearance with layout involving
more than 2 chillers, please contact application engineer-
ing.
Oversizing chillers
Oversizing chillers by more than 15% at design conditions
must be avoided as the system operating efficiency is
adversely affected (resulting in greater or excessive electri-
cal demand). When future expansion of equipment is
anticipated, install a single chiller to meet present load
requirements and add a second chiller to meet the addi-
tional load demand. It is also recommended that 2 smaller
chillers be installed where operation at minimum load is
critical. The operation of a smaller chiller loaded to a
greater percentage over minimum is preferred to operating
a single chiller at or near its minimum recommended value.
Hot gas bypass should not be used as a means to allow
oversizing chillers. Hot gas bypass should be given consid-
eration where substantial operating time is anticipated
below the minimum unloading step.
Multiple chillers
Where chiller capacities greater than can be supplied by a
single 30RAP chiller are required, or where stand-by
capability is desired, chillers may be installed in parallel.
Units may be of the same or different sizes with this piping
arrangement. However, cooler flow rates must be balanced
to ensure proper flow to each chiller.
When multiple 30RAP chillers are applied in parallel,
and the chillers include the optional hydronic package
which contain expansion tanks (sizes 010-060), the indi-
vidual chiller expansion tanks must be disconnected and a
single field-supplied expansion tank must be installed in the
common header.
Unit software is capable of controlling two parallel units
as a single plant by making use of the dual chiller control
feature. Refer to the Controls, Start-up, Operation, Service
and Troubleshooting guide for further details. The accesso-
ry Chillervisor System Manager can be used to ensure
proper staging sequence of up to 8 chillers. Refer to the
accessory Chillervisor System Manager installation instruc-
tions for further details.
If the dual chiller algorithm is used, and the machines are
installed in parallel, one chiller must be configured as the
master chiller and the other as the slave. With this configu-
ration, an additional leaving fluid temperature thermistor
must be installed as shown in the figure below.
Parallel chiller control with dedicated pumps is recom-
mended. The chiller must start and stop its own water
pump located in its own piping. Check valves are required
at the discharge of each pump (when the factory hydronic
package option is chosen, and dual pumps are select-
ed, the check valves are automatically supplied). If
pumps are not dedicated for each chiller, then isolation
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