Daikin Trailblazer AGZ030E-070E, Инструкция по установке, эксплуатации и обслуживанию

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IOM 1207-6 • TRAILBLAZER
®
MODEL AGZ CHILLERS 16 www.DaikinApplied.com
Installation and Application Information
Water systems should be cleaned and flushed prior to chiller
installation. Water testing and treatment should be verified
during initial chiller installation/commissioning and maintained
on a continuous basis by water treatment professionals (see
Limited Product Warranty).
CAUTION
The improper use of detergents, chemicals, and additives
in the chiller system water may adversely affect chiller
performance and potentially lead to repair costs not covered
by warranty. Any decision to use these products is at the
discretion of the owner/occupant/operator/user as such they
assume full liability/responsibility for any damage that may
occur due to their use.
Evaporator Freeze Protection
Evaporator freeze-up can be a concern in the application of
air-cooled water chillers in areas experiencing below freezing
temperatures. To protect against freeze-up, insulation and an
electric heater are furnished with the evaporator. Models 030
through 241 have an external plate heater and thermostat.
These heaters help protect the evaporator down to -20°F
(-29°C) ambient air temperature. The evaporator heater cable
is factory wired to the 115 volt control circuit transformer in the
control box. A 115V power source for the heater and controls
may also be supplied from a separate power feed to maximize
unit protection if desired. Refer to the field wiring diagram on
page 65 for additional information on supplying a separate
115V power feed.
Operation of the heaters is automatic through the ambient
sensing thermostat that energizes the evaporator heaters for
protection against freeze-up. Unless the evaporator is drained
in the winter or contains an adequate concentration of anti-
freeze, the disconnect switch to the evaporator heater must not
be open.
Although the evaporator is equipped with freeze protection, it
does not protect water piping external to the evaporator itself
if there is a power failure or heater burnout, or if the chiller
is unable to control the chilled water pumps. Use one of the
following recommendations for additional freeze protection:
1. If the unit will not be operated during the winter, drain the
evaporator and chilled water piping and flush with glycol.
2. Add a glycol solution to the chilled water system. Burst
protection should be approximately 10°F below minimum
design ambient temperature.
3. Insulate the exposed piping.
4. Add thermostatically controlled heat by wrapping the
lines with heat tape.
5. When glycol is added to the water system for freeze
protection, the refrigerant suction pressure will be lower,
cooling performance less, and water side pressure drop
greater. If the percentage of glycol is high, or if propylene
is used instead of ethylene glycol, the added pressure
drop and loss of performance could be substantial. When
Glycol or Ice are selected as Unit Mode, the MicroTech
®
III control will automatically reset the available range
for the Leaving Water Temperature, Freezestat and
Evaporator Pressure settings.
Chilled Water Pump
It is important that the chilled water pumps be wired to,
and controlled by, the chiller’s controller. When equipped
with optional dual pump output, the chiller controller has
the capability to selectively send the signal to a pump relay
(by others) to start pump A or B or automatically alternate
pump selection and also has standby operation capability.
The controller will energize the pump whenever at least one
circuit on the chiller is enabled to run, whether there is a
call for cooling or not. This helps ensure proper unit start-up
sequence. The pump will also be turned on when the water
temperature goes below the Freeze Setpoint for longer than a
specified time to help prevent evaporator freeze-up, provided
the disconnect is not closed. Connection points are shown in
the Field Wiring Diagram beginning on page 65 .
CAUTION
Adding glycol or draining the system is the recommended
method of freeze protection. If the chiller does not have
the ability to control the pumps and the water system is
not drained in temperatures below freezing, catastrophic
evaporator failure may occur.
Failure to allow pump control by the chiller may cause the
following problems:
1. If any device other than the chiller attempts to start the
chiller without first starting the pump, the chiller will lock
out on the No Flow alarm and require manual reset.
2. If the chiller evaporator water temperature drops below
the “Freeze setpoint” the chiller will attempt to start the
water pumps to avoid evaporator freeze. If the chiller
does not have the ability to start the pumps, the chiller
will alarm due to lack of water flow.
3. If the chiller does not have the ability to control the
pumps and the water system is not to be drained in
temperatures below freezing or contain glycol, the chiller
may be subject to catastrophic evaporator failure due to
freezing. The freeze rating of the evaporator is based on
the evaporator heater and pump operation. The external
brazed plate heater itself may not be able to properly
protect the evaporator from freezing without circulation
of water.
All chillers with the optional pump package are factory wired for
control by the chiller.