Carrier Packaged and Dedicated Outdoor Air Units 50TC

Warning: Failure to follow this NOTICE can result in an unnecessary evacuation of the facility.

If the smoke detector is connected to a fire alarm system, first notify the proper authorities that the detector is undergoing maintenance then disable the relevant circuit to avoid generating a false alarm.

Disconnect power from the duct detector then remove the sensor’s cover.

Using a vacuum cleaner, clean compressed air, or a soft bristle brush, remove loose dirt and debris from inside the sensor housing and cover.

Use isopropyl alcohol and a lint-free cloth to remove dirt and other contaminants from the gasket on the sensor’s cover.

Squeeze the retainer clips on both sides of the optic housing then lift the housing away from the printed circuit board.

Gently remove dirt and debris from around the optic plate and inside the optic housing.

Replace the optic housing and sensor cover.

Connect power to the duct detector then perform a sensor alarm test.

CAUTION: PERSONAL INJURY HAZARD. Always wear approved safety glasses, work gloves and other recommended Personal Protective Equipment (PPE) when working with refrigerants.

Disconnect all AC power to the unit. Use approved lockout/ tag-out procedures.

Using the gage set approved for use with Puron (R-410A) refrigerant, recover all refrigerant from the system.

Disconnect the liquid line at the TXV inlet.

Remove the liquid line connection at the TXV inlet.

Remove the equalizer tube from the suction line of the coil. Use a tubing cutter to cut the brazed equalizer line approximately 2-in. (50 mm) above the suction tube.

Remove the bulb from the vapor tube above the evaporator coil header outlet.

Install the new TXV; avoid damage to the tubing or the valve when attaching the TXV to the distributor. Protect the TXV against over-temperature conditions by using wet rags and directing the torch flame tip away from the TXV body.

Shut off the unit power supply and apply the appropriate lockout/tagout procedures

Remove the condenser-fan assembly (grille, motor, and fan)

Upload a photo of the adjusted fan height as shown in Fig. 32

Replace the condenser-fan assembly

Sign off on the condenser-fan adjustment

CAUTION: EQUIPMENT DAMAGE HAZARD. Failure to follow this CAUTION can result in premature wear and damage to equipment.

Use a belt with same section type or similar size. Do not substitute a “FHP” or notched type V-belt.

Loosen (turn counterclockwise) the motor mounting plate front bolts and rear bolts.

Loosen (turn counterclockwise) the jack bolt lock nuts. Loosen (turn counterclockwise) the jack bolts, relieving the belt tension and allowing easy removal of the belt by hand.

Remove the belt by gently lifting the old belt over one of the pulleys.

Install the new belt by gently sliding the belt over both pulleys, then tighten (turn clockwise) the jack bolts, sliding the motor plate away from the fan housing until proper belt tension is achieved.

Check the alignment of the pulleys, adjust if necessary.

Tighten all bolts attaching the motor to the motor plate.

Tighten all jack bolt jam nuts by turning clockwise.

Warning: This procedure requires trained personnel with PPE!

Connect service gages to suction and discharge pressure fittings

Check if suction pressure drops and discharge pressure rises

If the suction pressure does not drop and the discharge pressure does not rise to normal levels:

Check if the evaporator fan is rotating in the wrong direction

Turn off power to the unit. Use applicable lockout/tag-out procedures

Reverse any two of the unit power leads

Reapply power to the compressor