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If the water circuit must be emptied for longer than one
month, the complete circuit must be placed under nitrogen
charge to avoid any risk of corrosion by differential aeration.
ATTENTION: Filling, completing and draining the water
circuit charge must be done by qualified personnel, using the
air purges and materials that are suitable for the products.
Charging and removing heat exchange fluids should be
done with devices that must be included on the water
circuit by the installer. Never use the unit heat exchangers
to add heat exchange fluid.
7.2 - Water connections
The diagrams on the following page illustrate a typical
hydronic installation. When the hydronic circuit is filled,
use the air vents to evacuate any residual air pockets.
7.3 - Frost protection
The 30RW and 30RWA units are designed to be installed
under cover at outside temperatures b5°C and
+40°C. Therefore they do not include anti-freeze protection,
as standard.
If the water piping is in an area where the ambient tempera-
ture can fall below 0°C it is recommended to install a trace
heater on the piping and 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.
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
heat exchanger water entering purge valve connection.
•
At the start of the next season, refill the unit with water
and add an inhibitor.
•
For the installation of auxiliary equipment, the installer
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).
To avoid corrosion by differential aeration, the
complete heat exchange circuit must be charged with
nitrogen, if it is drained for longer than one month. If
the heat exchange fluid does not comply with Carrier
recommendations, the circuit must immediately be
filled with nitrogen.
7.4 - Evaporator flow switch and chilled water pump
interlock (units without hydronic module)
IMPORTANT: On 30RW and 30RWA units, the unit
water flow switch must be energised, and the chilled water
pump interlock must be connected. Failure to follow this
instruction will void the Carrier guarantee.
The flow switch is supplied, installed on the evaporator
entering water pipe and preset at the factory to cut out
when there is insufficient water flow.
Terminals 34 and 35 are provided for field installation of
the chilled water pump interlock (auxiliary contact for
pump operation to be wired on site).
