Carrier Aquasnap 30RAP010, Product Data

Page: 62 / 76

62
valves are required. Each chiller must open and close its
own isolation valve through the unit control (the valve must
be connected to the pump outputs).
If a series application is required, the master/slave con-
trol feature cannot be used. Hydronic pump packages may
not be applied in series applications.
For 30RAP070-090 units, when chillers are arranged in
parallel, a minimum of 10 ft (3048 mm) between chillers is
recommended. Acceptable clearance on the cooler connec-
tion side or end opposite the control box of the unit can be
reduced to 3 ft (1 m) without sacrificing performance as
long as the remaining three sides are unrestricted. Accept-
able clearance on the side with a control box can be re-
duced 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 sacrificing performance provided the re-
maining sides are unrestricted. For acceptable clearance
with layout involving more than 2 chillers, please contact
application engineering.
Series chillers
Where a large temperature drop (greater than 20 F
[11.1 C]) is desired or where chiller capacities greater than
can be supplied by a single 30RAP chiller are required or
where standby capability is required, chillers may be
installed in series. The leaving fluid temperature sensors
need not be relocated. However, the cooler minimum
entering fluid temperature limitations should be considered
for the chillers located downstream of other chillers. When
chillers are operated in a series arrangement, the use of a
Chillervisor System Manager is recommended.
Cooler water temperature
1. Maximum leaving chilled water temperature (LCWT)
for the unit is 60 F (15.6 C). Unit can start and pull
down with up to 95 F (35 C) entering-water tempera-
ture. It is recommended that entering-water tempera-
ture not exceed 70 F (21.1 C).
2. Minimum LCWT for fresh water applications is 40 F
(4.4 C). For leaving-fluid temperatures between 14
and 39.9 F (–10.0 C and 4.4 C) an inhibited anti-
freeze solution in the fluid loop is required, but no
modification to the 30RAP chiller (accessory medium
temperature brine, for example) is required.
NOTE: Water flowing through cooler should not exceed
100 F (38 C).
NOTE: The 30RAP chiller does not require a medium tem-
perature brine modification at any temperature within the
chiller application range which is as low as 14 F (–10 C)
leaving fluid temperature.
Strainers
A 40 mesh strainer is installed in the cooler fluid inlet line,
just ahead of the cooler.
Cooler flow/range
Ratings and performance data in this publication are for a
cooling temperature rise of 10° F (6° C). The 30RAP chill-
ers may be operated at a different temperature rise, provid-
ing flow limits are not exceeded and corrections to system
guidelines are made. For minimum and maximum cooler
flow rates, see the Minimum and Maximum Cooler Flow
Rates table. A high flow rate is generally limited by the
maximum pressure drop that can be tolerated by the unit.
The 30RAP chillers are designed for a full load tempera-
ture rise of 5° to 20° F (2.8° to 11. 1° C). Use the Pack-
aged Chiller Builder Program to obtain the rating if a
temperature rise other than 10° F (6° C) is used.
Minimum cooler flow (maximum cooler tempera-
ture rise) —
The minimum cooler flow for standard units
is shown in Minimum and Maximum Cooler Fluid Flow
Rates table. When system design conditions require a
lower flow (or higher rise) than the minimum allowable
cooler flow, follow the recommendations below.
• Multiple smaller chillers may be applied in series, each
providing a portion of the design temperature rise.
• Cooler fluid may be recirculated to raise the flow rate to
the chiller. The mixed temperature entering the cooler
must be maintained to a minimum of at least 5° F
(2.8° C) above the LCWT and to a maximum of no
more than 20° F (11.1° C) above the LCWT.
NOTE: Recirculation flow is shown below.
Maximum cooler flow — The maximum cooler flow
(approximately 5° F [2.8° C] rise) results in a practical max-
imum pressure drop through cooler.
Return fluid may bypass the cooler to keep the pressure
drop through the cooler within acceptable limits. This per-
mits a higher delta T with lower fluid flow through cooler
and mixing after the cooler. The mixed temperature enter-
ing the cooler must be maintained to a minimum of at least
5° F (2.8° C) above the LCWT and to a maximum of no
more than 20° F (11.1° C) above the LCWT.
MASTER
CHILLER
SLAVE
CHILLER
LEAVING
FLUID
RETURN
FLUID
THERMISTOR
WIRING*
INSTALL DUAL CHILLER LWT
LEAVING FLUID TEMPERATURE
THERMISTOR (T10) HERE
*Depending on piping sizes, use either:
• HH79NZ014 sensor/10HB50106801 well (3-in. sensor/well)
• HH79NZ029 sensor/10HB50106802 well (4-in. sensor/well)
PARALLEL CHILLER INSTALLATION
RECIRCULATION FLOW
a30-4042
Application data