7.3 -
Water flow detection
7.3.1 -
Standard unit
All units are equipped with a factory-set flow switch. It cannot be
adjusted on site.
A water pump operating interlock must be wired to the unit if no
hydraulic module is fitted. Terminals 34 and 35 are provided for
connection of the water pump interlock (to be wired on site).
7.3.2 -
Unit with hydraulic module (options 116)
The ‘‘water flow detection’’ functionality is handled by the option
(via pressure sensors).
7.4 -
Frost protection
CAUTION: Damage caused by frost is not covered by the
warranty.
The plate heat exchanger, the pipes and the hydraulic module
pumps can be damaged by frost. The components of the unit (heat
exchanger, pipes, hydraulic module) will be protected by following
the recommendations below. Protection of the remainder of the
system is the responsibility of the installer.
7.4.1 -
Standard unit
If the chiller or the water pipes are in an area where the ambient
temperature can drop below 0°C, it is recommended that one of
the three following strategies is applied to protect the unit and the
water pipes down to a temperature 10 K below the lowest
temperature likely to occur locally:
1. Add an anti-freeze solution (45% maximum);
2. Drain the hydraulic circuits exposed to negative temperatures;
3. Solution with heaters: Order (factory-installed) option 41
(electric heaters on the water heat exchanger and exchanger
water outlet pipes) in order to protect the exchanger down to
-20°C. If option 266 (water heat exchanger connection sleeves)
is also ordered, it is necessary to install a heater on each
extension in order to protect the water pipes down to outdoor
temperatures of -20°C. The anti-freeze and heater solutions
can be combined.
7.4.2 -
Unit with hydraulic module
The recommendations from the previous chapter (points 1 and 2)
are applicable to the machines with hydraulic module and protect
them against frost.
For the solution with heaters, order (factory-installed) option 42A
(electric heaters on the water heat exchanger and various
components of the hydraulic module including the expansion tank)
to ensure protection of the entire unit down to -20°C. The anti-
freeze and heater solutions can be combined.
Frost protection of units with hydraulic modules require that water
be circulated in the hydraulic circuit. The pump will periodically
start automatically.
Combination of options for the periods when the machine is in
standby mode.
Ambient unit
temperature range
30RQM/30RQP 160-520
without option 116
with option 116
> 0°C to 48°C
-
-
-20°C to 0°C
Option 41
Option 42A
(1)
or
or
Appropriate anti-freeze
solution (for example
glycol)
Appropriate anti-freeze
solution (for example
glycol)
(1)
(1) Allow the pumps to circulate. If there is a valve, install a bypass (see diagram
for winter position).
If the system is isolated by a valve, it is imperative to install a
bypass as indicated below.
Winter position
Unit
Water system
Closed
Closed
Open
IMPORTANT REMINDERS: Depending on the atmospheric
conditions in your region, you need to:
-
Add an appropriate anti-freeze solution to protect the
system down to a temperature of 10 K below the lowest
temperature likely to occur locally.
-
For extended shut-downs, drain and add an anti-freeze
solution to the heat exchanger (use the drain valve
located at the water inlet).
-
To prevent corrosion due to differential aeration, if the
system is to be empty for more than 1 month, the heat
transfer fluid circuit should be protected with a blanket
of dry, inert gas. (0.5 bar maximum). If the heat transfer
fluid does not meet Carrier's recommendations, a
nitrogen blanket must be applied immediately.
-
In case of prolonged non-usage, the hydraulic circuits
must be protected by circulating a passivating solution.
(Consult a specialist).
-
At the commencement of the next season, fill the system
with water treated with appropriate corrosion inhibitors.
-
If auxiliary equipment is installed in the system, the
installer must ensure that the resultant flow rates are
still within the minimum and maximum values indicated
in the operating limits table (application data).
-
If frost protection is dependent on electric heaters, never
deenergize the unit when frost protection is required. To
ensure protection, the main unit disconnect switch,
auxiliary heater circuit and the control circuit must be
energized (see wiring diagram to locate these
components). If it is not to be used in freezing conditions,
or during a prolonged power failure (planned or
unplanned), the water heat exchanger and external pipes
must be drained without delay. Damage caused by frost
is not covered by the warranty.
-
The heat exchanger temperature sensors are part of its
frost protection: If piping trace heaters are used, ensure
the external heaters do not affect the measurements
provided by these sensors.
7 - WATER CONNECTIONS
31
Summary of Contents for Carrier 30RQM 160
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