Start-Up And Operation; Actual Start-Up; Operating Limitations; Temperatures - Carrier Air Conditioner Operation And Service Manual

START-UP AND OPERATION

NOTE: Refer to Start-Up Checklist on pages CL-1 to CL-8.
Actual Start-Up —
Actual start-up should be done only
under supervision of a qualified refrigeration mechanic.
1. Be sure all service valves are open. Units are shipped
from factory with suction, discharge, and liquid line
service valves closed.
2. Using the Marquee display, set leaving-fluid set point
(CSP.1 is Set Point mode under sub-mode COOL). No
cooling range adjustment is necessary.
3. If optional control functions or accessories are being
used, the unit must be properly configured. Refer to Op-
erating Data section for details.
4. Start chilled fluid pump.
5. Turn ENABLE/OFF/REMOTE CONTACT switch to
ENABLE position.
6. Allow unit to operate and confirm that everything is func-
tioning properly. Check to see that leaving fluid tempera-
ture agrees with leaving set point (CSP.1 or CSP.2), or if
reset is used, with the control point (CTPT) in the Run
Status mode under the sub-mode VIEW.

Operating Limitations

TEMPERATURES (See Table 35) — If unit is to be used in
an area with high solar radiation, mounted position should be
such that control box is not exposed to direct solar radiation.
Exposure to direct solar radiation could affect the temperature
switch controlling cooler heaters.
Table 35 — Temperature Limits for Standard Units
TEMPERATURE
Maximum Ambient Temperature
Minimum Ambient Temperature
Maximum Cooler EWT*
Maximum Cooler LWT
Minimum Cooler LWT†
LEGEND
EWT — Entering Fluid (Water) Temperature
LWT — Leaving Fluid (Water) Temperature
*For sustained operation, EWT should not exceed 85 F (29.4 C).
†Unit requires modification below this temperature.
Low-Ambient Operation — If operating temperatures below
0° F (–18 C) are expected, refer to separate installation instruc-
tions for low-ambient operation using accessory Motor-
master® III control. Contact your Carrier representative for
details.
NOTE: Wind baffles and brackets must be field-fabricated for
all units using accessory Motormaster III controls to ensure
proper cooling cycle operation at low-ambient temperatures.
See Installation Instructions shipped with the Motormaster III
accessory for more details.
Brine duty application (below 38 F [3.3 C] LCWT) for
chiller normally requires factory modification. Contact
your Carrier representative for applicable LCWT range for
standard water-cooled chiller in a specific application.

VOLTAGE

Main Power Supply — Minimum and maximum acceptable
supply voltages are listed in the Installation Instructions.
Unbalanced 3-Phase Supply Voltage — Never operate a motor
where a phase imbalance between phases is greater than 2%.
To determine percent voltage imbalance:
% Voltage Imbalance = 100 x
The maximum voltage deviation is the largest difference
between a voltage measurement across 2 legs and the average
across all 3 legs.
Example: Supply voltage is 240-3-60.
AB = 243 v
BC = 236 v
AC = 238 v
1. Determine average voltage:
2. Determine maximum deviation from average voltage:
3. Determine percent voltage imbalance:
F C
125 52
0 –18
95 35
70 21
38 3.3 This voltage imbalance is satisfactory as it is below the
maximum allowable of 2%.
IMPORTANT: If the supply voltage phase imbalance is
more than 2%, contact your local electric utility com-
pany immediately. Do not operate unit until imbalance
condition is corrected.
Control Circuit Power — Electronic control includes logic to
detect low control circuit voltage. Acceptable voltage ranges
are shown in the Installation Instructions.
MINIMUM FLUID LOOP VOLUME — To obtain proper
temperature control, loop fluid volume must be at least 3 gal-
lons per ton (3.25 L per kW) of chiller nominal capacity for air
conditioning and at least 6 gallons per ton (6.5 L per kW) for
process applications or systems that must operate at low ambi-
ent temperatures (below 32 F [0° C]). Refer to application
information in Product Data literature for details.
FLOW RATE REQUIREMENTS — Standard chillers
should be applied with nominal flow rates approximating those
listed in Table 36. Higher or lower flow rates are permissible to
obtain lower or higher temperature rises. Minimum flow rates
must be exceeded to assure turbulent flow and proper heat
transfer in the cooler.
Operation below minimum flow rate could subject tubes to
frost pinching in tube sheet, resulting in failure of cooler.
66
243 + 236 + 238
Average voltage =
3
717
=
3
239
=
(AB) 243 – 239 = 4 v
(BC) 239 – 236 = 3 v
(AC) 239 – 238 = 1 v
Maximum deviation is 4 v.
% Voltage Imbalance = 100 x
= 1.7%
max voltage deviation
from avg voltage
average voltage
4
239