Carrier 50NQ - Manual (Page 9)

d. Make sure that all tools and miscellaneous loose
parts have been removed.
Unit is now ready for initial steirtup.
REFRIGERANT LEAKS
Proceed as follows to repair a refrigerant leak and to charge
the unit:
1. Locate leak and ensure that refrigerant system pres­
sure has been relieved.
2. Repeiir 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. Evacuate refrigerant system if additional leaks are not
found.
5. Charge unit with R-22 refrigerant, using a volumetric-
charging cylinder or accurate scede. Refer to unit rating
plate for required charge. Be sure to add extra refriger­
ant to compensate for internal volume of filter-drier.
START-UP AND ADJUSTMENTS
A CAUTION
Complete the required procedures given in “Preparing
Unit for Start-up,” page 7, before starting the unit.
Do not jumper any safety devices when operating the
unit.
Do not operate unit in the cooling mode when the out­
door temperature is below 55 F (unless accessory low-
temperature kit is installed).
Do not operate unit in heating mode when outdoor tem­
perature is above 60 F.
Do not rapid-cycle the compressor. Allow 5 minutes
between “on” cycles to prevent compressor damage.
The unit compressor is equipped with a crankcase heater. It
is recommended that heater be energized a minimum of 24
hours before starting unit. To energize heater only, set ther­
mostat at OFF position; turn on unit main power at discon­
nect switch.
TO START UNIT—Check that main power is on and that
compressor crankcase heater has been energized for at least
24 hours.
1. Check that heater main power is on as applicable.
2. Set selector switch at OFF.
3. Set fan switch as desired (FAN) (AUTO.).
4. Set thermostat dial at the desired temperature.
5. Set selector switch at HEAT or COOL. Check system
refrigerant charge as described in “Checking Charge”
section below.
CHECKING CHARGE-Factory Charge is shown on unit
rating plate (See Fig. 4).
A CAUTION
Compressor damage may occur if system is over­
charged.
Adjust charge in cooling mode by following procedure
shown on the “superheat charging tables” located on unit.
Check charge in heating by following procedure shown on
“heating check chart” located on unit.