Start- -Up Adjustments; Checking Cooling Control Operation; Checking And Adjusting Refrigerant Charge - Carrier 50SD030 Installation Instructions Manual

LEGEND
FLA — Full Load Amps
LRA — Locked Rotor Amps
MCA -- Minimum Circuit Amps
MOCP — Maximum Overcurrent Protection
RLA — Rated Load Amps
NO TES:
1. In compliance with NEC (National Electrical Code) requirements
for multimotor and combination load equipment (refer to NE C
Articles 430 and 440), the overcurrent protective device for the
unit shall be Power
Association) units may be fuse or circuit break er.
2. Minimum wire size is based on 60 C copper wire. I f other than
o
60 C wire is used, or if length exceeds wire length in table,
determine siz e from NEC.
3. Unbalanced 3-Phase Supply Voltage
Never operate a motor where a phase imbalance in supply volt-
age is greater than 2%. Use the following formula to determine
the percentage of voltage imbalance.
% Voltage imbalance
max voltage deviation from average voltage
= 100 x
Heater capacity (kW) based on heater voltage of 208v & 240v.
*
If power distribution voltage to unit varies from rated heater
voltage, heater kW will vary accordingly.
1. Locate leak and make sure that refrigerant system pressure
has been relieved and reclaimed from both high- - and
low- -pressure ports.
2. Repair leak following accepted practices.
NOTE: Install a filter drier whenever the system has been opened
for repair.
3. Add a small charge of R- -22 refrigerant vapor to system and
leak- -test unit.
4. Recover refrigerant from system and evacuate to 500
microns if no additional leaks are found.
5. Charge unit with R- -22 refrigerant, using a volumetric
charging cylinder or accurate scale. Refer to unit rating plate
for required charge. Be sure to add extra refrigerant to
compensate for internal volume of filter drier.
START- -UP COOLING
ADJUSTMENTS
Complete the required procedures given in the Pre- -Start- -Up
section before starting the unit. Do not jumper any safety devices
when operating the unit. Do not operate the unit when the outdoor
temperature is below 40°F (unless accessory low- -ambient kit is
installed). Do not rapid cycle the compressor. Allow 5 minutes
between "on" cycles to prevent compressor damage.

CHECKING COOLING CONTROL OPERATION

Start and check the unit for proper cooling control operation as
follows:
1. Place room thermostat SYSTEM switch in OFF position.
Observe that blower motor starts when FAN switch is placed
in ON position and shuts down after 30 second fan time
delay expires when FAN switch is placed in AUTO position.
2. Place SYSTEM switch in COOL position and FAN switch
in AUTO position. Set cooling control below room
temperature. Observe that compressor, condenser fan, and
evaporator blower motors start. Observe that compressor
and outdoor fan shut down when control setting is satisfied
and that indoor blower shuts down after 30 second fan time
delay expires.
IMPORTANT: Three- -phase, scroll compressors are direction
oriented. Unit must be checked to ensure proper compressor
3- -phase power lead orientation. If not corrected within 5 minutes,
the internal protector will shut off the compressor. The 3- -phase
power leads to the unit must be reversed to correct rotation. When
turning backwards, the difference between compressor suction and
discharge pressures may be dramatically lower than normal.

CHECKING AND ADJUSTING REFRIGERANT CHARGE

The refrigerant system is fully charged with R- -22 refrigerant and
is tested and factory sealed.
®
Supply fuse. The CGA (Canadian Gas
o
.
average voltage
SECTION AND MAKE
EXAMPLE: Supply voltage is 230-3-60.
AB = 228 v
BC = 231 v
AC = 227 v
Average Voltage =
Determine maximum deviation from average voltage.
(AB) 229 - 228 = 1 v
(BC) 231 - 229 = 2 v
(AC) 229 - 227 = 2 v
Maximum deviation is 2 v.
Determine percent of voltage imbalance.
2
% Voltage Imbalance = 100 x
229
= 0.8%
This amount of phase imbalance is satisfactory as it is below the
maximum allowable 2%.
IMPORTANT: If the supply voltage phase imbalance is
more than 2%, contact your local electric utility company
immediately.
NOTE: Adjustment of the refrigerant charge is not required unless
the unit is suspected of not having the proper R- -22 charge.
A superheat charging chart is attached to the outside of the service
access panel. The chart includes the required suction line
temperature at given suction line pressures and outdoor ambient
temperatures.
An accurate superheat, thermocouple- - or thermistor- -type
thermometer, and a gauge manifold are required when using the
superheat charging method for evaluating the unit charge. Do not
use mercury or small dial- -type thermometers because they are not
adequate for this type of measurement.
NOTE: Allow system to operate for a minimum of 10 minutes
before checking or adjusting refrigerant charge.
IMPORTANT: When evaluating the refrigerant charge, an
indicated adjustment to the specified factory charge must always be
very minimal. If a substantial adjustment is indicated, an abnormal
condition exists somewhere in the cooling system, such as
insufficient airflow across either coil or both coils.
Proceed as follows:
1. Remove caps from low- - and high- -pressure service fittings.
2. Using hoses with valve core depressors, attach low- - and
high- -pressure gauge hoses to low- - and high- -pressure
service fittings, respectively.
3. Start unit and let run until system pressures stabilize.
4. Measure and record the following:
a. Outdoor ambient- -air temperature (°F db).
b. Suction- -tube temperature (°F) at low- -side service fitting.
c. Suction (low- -side) pressure (psig).
5. Using Cooling Charging Charts compare outdoor- -air
temperature (°F db) with the suction line pressure (psig) to
determine desired system operating suction line temperature
(See Fig. 16).
6. Compare actual suction- -tube temperature with desired
suction- -tube temperature. Using a tolerance of ±3°F, add
refrigerant if actual temperature is more than 3°F higher than
proper suction- -tube temperature, or remove refrigerant if
actual temperature is more than 3°F lower than required
suction- -tube temperature.
NOTE: If the problem causing the inaccurate readings is a
refrigerant leak, refer to Check for Refrigerant Leaks section.
12
228 + 231 + 227
3
686
=
3
= 229
C03014