Preparation For Year-Round Operation - Carrier AquaForce 30XA Series Installation Instructions Manual

CAUTION
Operation with fresh water is not fail-safe should there be a
loss of power to the chiller or to the circulating pump. Freeze
damage due to power loss or disabling chiller pump control in
fresh water systems will impair or otherwise negatively affect
the warranty.
If cooler pump control is not utilized, it is required that the chiller
be electrically interlocked with the chilled water pump starter. The
interlock should be wired to terminals TB5-1 and TB5-2. It is also
recommended that the cooler pump output be used as an override
to the chilled water pump control circuit to provide additional
freeze protection.
Refer to the control and power wiring sections beginning on
page 133 for proper connection of the cooler pump output (PMP1
and PMP2). The cooler pump output will remain energized for 30
seconds after all compressors stop due to an OFF command. In the
event a freeze protection alarm is generated, the cooler pump out-
put will be energized regardless of the cooler pump control soft-
ware configuration. The cooler pump output is also energized any-
time a compressor is started and when certain alarms are generat-
ed. A thermal flow sensor is factory installed in the leaving fluid
nozzle to prevent operation without flow through the cooler. See
Fig. 48. The flow sensor is factory wired.
Proper software configuration of the cooler pump control parame-
ters is required to prevent possible cooler freeze-up. Refer to the
Controls, Start-Up, Operation, Service and Troubleshooting guide
for more information.
DX Cooler Brine Units
For operating units with fluid temperatures less than 40°F (4.4°C),
add sufficient inhibited glycol or other suitable corrosion-resistant
antifreeze solution to prevent cooler freeze-up.

PREPARATION FOR YEAR-ROUND OPERATION

In areas where the piping or unit is exposed to 32°F (0C) or lower
ambient temperatures, freeze-up protection is required using in-
hibited glycol or other suitable corrosion-resistant antifreeze solu-
tion and electric heater tapes. Heater tapes on piping should have a
rating for area ambient temperatures and be covered with a suit-
able thickness of closed-cell insulation. Route power for the heater
tapes from a separately fused disconnect. Mount the disconnect
within sight from the unit per local or NEC (National Electric
Code) codes. Identify disconnect at heater tape power source with
a warning that power must not be turned off except when servic-
ing unit.
IMPORTANT: Adding antifreeze solution is the only
certain means of protecting the unit from freeze-up if
heater fails or electrical power is interrupted or lost
while temperatures are below 32°F (0C).
A drain connection is located at the bottom of the cooler head or
bottom of cooler shell. See Fig. 2-27 for connection location. In-
stall shut-off valves to the drain line before filling the system with
fluid.
Low Ambient Temperature Head Pressure Control
If the unit is equipped with the low ambient temperature head
pressure control option, field-fabricated and field-installed wind
baffles are required if the wind velocity is anticipated to be greater
than 5 mph (8 km/h). Two different baffles may be required, fac-
ing the control box. Wind baffles should be constructed with mini-
mum 18-gage galvanized sheet metal or other suitable corrosion-
resistance material with cross breaks for strength. See Fig. 53. Use
field-supplied screws to attach baffles to the corner posts of the
machine. Be sure to hem or turn a flange on all edges to eliminate
sharp edges on the baffles.
Disconnect all power to the unit before performing mainte-
nance or service. Electrical shock and personal injury could re-
sult.
To avoid damage to the refrigerant coils and electrical compo-
nents, use extreme care when drilling screw holes and screw-
ing in fasteners.
Mount the smaller height baffle on units with a control box located
on the end of the unit. It is recommended that the upper notches be
used for mounting the baffles. This reduces the risk of damaging
the coil while drilling a mounting hole. Loosen the upper corner
post bolts and slide the baffle under the bolt and washer. Tighten
the bolt. Drill holes in the bottom of the flange of the baffle and
mount with two screws to secure the bottom of the baffle to the
corner post. Repeat the process for the opposite end. See Fig. 53.
127
WARNING
CAUTION