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7.3 - Flow control
Evaporator flow switch and chilled water pump interlock
IMPORTANT: On 30XA units, the unit water flow switch
must be energised. Failure to follow this instruction will
void the Carrier guarantee.
The water flow switch is installed on the evaporator water
inlet and adjusted by the control, based on unit size and
application. If adjustment is necessary, it must be carried
out by qualified personnel trained by Carrier Service.
7.4 - Evaporator water box bolt tightening
The evaporator (and condenser) are of the shell and tube
type with removable water boxes to facilitate cleaning.
Re-tightening or tightening must be done in accordance
with the illustration below.
Water box tightening sequence
Legend:
1
Sequence 1: 1, 2, 3, 4
Sequence 2: 5, 6, 7, 8
Sequence 3: 9, 10, 11, 12
Sequence 4: 13, 14, 15, 16
NOTE: Before this operation we recommend draining the
circuit and disconnecting the pipes to be sure that the bolts
are correctly and uniformly tightened.
7.5 - Frost protection
7.5.1 - Standard machine
If the chiller or the water piping is in an area where the
ambient temperature can fall below 0 °C it is
recommended to add an antifreeze solution to protect the
unit and the water piping to a temperature of 10 K below
the lowest temperature likely to be reached at the
installation site. Use only antifreeze solutions, approved
for heat exchanger duty. If the system is not protected by
an antifreeze solution and will not be used during the
freezing weather conditions, draining of the cooler and
outdoor piping is mandatory. Damage due to freezing is
not covered by the warranty.
34
2
Tightening torque
Bolt size M16 - 171 - 210 Nm
IMPORTANT: Depending on the climatic conditions in
your area you must:
•
Add ethylene glycol with an adequate concentration
to protect the installation up to a temperature of 10 K
below the lowest temperature likely to occur at the
installation site.
•
If the unit is not used for an extended period, it is
recommended to drain it, and as a safety precaution
add ethylene glycol to the heat exchanger, using the
water entering purge valve connection (a purge connec-
tion is available somewhere on the heat exchanger
water box in case the machine is not perfectly level).
•
At the start of the next season, refill the unit with water
and add an inhibitor.
•
For the installation of auxiliary equipment, the
instal-ler must comply with basic regulations,
especially for minimum and maximum flow rates,
which must be between the values listed in the
operating limit table (application data).
7.5.2 - Optional evaporator frost protection (30XA)
In cases where it is not possible to apply the recommenda-
tions in paragraph 7.5.1, the units can be equipped with
heaters to protect the evaporator against frost (option 41A
or 41B).
7.6 - Operation of two units in master/slave mode
(option 58)
NOTE: This operating mode is not available for 30XA
1702 units.
The control of a master/slave assembly is in the entering
water and does not require any additional sensors (standard
configuration). It can also be located in the leaving water.
In this case two additional sensors must be added on the
common piping.
All parameters, required for the master/slave function must
be configured using the Service Configuration menu. All
remote controls of the master/slave assembly (start/stop,
set point, load shedding etc.) are controlled by the unit
con-figured as master and must only be applied to the
master unit.
Each unit controls its own water pump. If there is only one
common pump, in cases with variable flow, isolation valves
must be installed on each unit. They will be activated at the
opening and closing by the control of each heat pump (in
this case the valves are controlled using the dedicated water
pump outputs). Refer to the 30XA/30XAS/30XW Touch
Pilot control manual for a more detailed explanation.
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