Carrier 50GS, 50GX instruction manual Start-Up, Start UP Cooling Section and Make ADJUST- Ments

leak. Leak test all refrigerant tubing connections using electronic leak detector, halide torch, or liquid-soap solu- tion. If a refrigerant leak is detected, see Check for Refrigerant Leaks section.

c.Inspect all field- and factory-wiring connections. Be sure that connections are completed and tight.

d.Ensure electrical wiring does not contact refrigerant tubes or sharp metal edges.

e.Inspect coil fins. If damaged during shipping and handling, carefully straighten fins with a fin comb.

Verify the following conditions:

a.Make sure that condenser-fan blade is correctly positioned in fan orifice. Leading edge of condenser-fan blade should be 1/2 in. maximum from fan orifice (See Fig. 11).

b.Make sure that air filter(s) is in place.

c.Make sure that condensate drain trap is filled with water to ensure proper drainage.

d.Make sure that all tools and miscellaneous loose parts have been removed.

START-UP

CHECK FOR REFRIGERANT LEAKS

Proceed as follows to locate and repair a refrigerant leak and to charge the unit:

1.Locate leak and make sure that refrigerant system pressure has been relieved and reclaimed from both high- and low-pressure ports.

START UP COOLING SECTION AND MAKE ADJUST- MENTS

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 compres- sor 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.
3.	When using an auto-changeover room thermostat, place both
	SYSTEM and FAN switches in AUTO positions. Observe that
	unit operates in heating mode when temperature control is set
	to “call for heating” (above room temperature) and operates in

MOTOR

1/8" MAX BETWEEN

MOTOR AND FAN HUB

FAN GRILLE

1/2˝

MOTOR SHAFT

C99009

cooling mode when temperature control is set to “call for

cooling” (below room temperature).

IMPORTANT: Three-phase, scroll compressor units (50GS048, 50GX030-060) are direction-oriented. These units must be checked to ensure proper compressor 3-phase power lead orienta- tion. 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, scroll compressors emit elevated noise levels, and the difference between

Fig. 11—Fan Blade Clearance

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 refrigerant system and evacuate to 500 microns if no additional leaks are not 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.

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, tested, and factory-sealed.

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 tempera- ture at given suction line pressures and outdoor ambient tempera- tures (See Fig. 15–27).

An accurate superheat, thermocouple- or thermistor-type ther- mometer, a sling psychrometer, 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 in the cooling mode for a minimum of 10 minutes before checking or adjusting refrigerant charge.

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