Carrier 48MA/50ME016-040 specifications Safety Considerations, Installation

SAFETY CONSIDERATIONS

Installation and servicing of air-conditioning equipment can be hazardous due to system pressure and electrical com- ponents. Only trained and quali®ed service personnel should install, repair, or service air-conditioning equipment.

Untrained personnel can perform basic maintenance func- tions of cleaning coils and ®lters and replacing ®lters. All other operations should be performed by trained service per- sonnel. When working on air-conditioning equipment, ob- serve precautions in the literature, tags and labels attached to the unit, and other safety precautions that may apply.

Follow all safety codes, including ANSI (American National Standards Institute) Z223.1. Wear safety glasses and work gloves. Use quenching cloth for unbrazing operations. Have ®re extinguisher available for all brazing operations.

Before performing service or maintenance operations on unit, turn off main power switch to unit. Electrical shock could cause personal injury.

Do not try to light any appliance. Do not touch any elec- trical switch; do not use any phone in your building. Immediately call your gas supplier from a neighbor's phone. Follow the gas supplier's instructions. If you can- not reach your gas supplier, call the ®re department.

Do not store or use gasoline or other ¯ammable vapors and liquids in the vicinity of the 48MA unit or any other gas-®red appliance.

Improper installation, adjustment, alteration, service, or maintenance can cause injury or property damage. Re- fer to this manual. For assistance or additional infor- mation, consult a quali®ed installer, service agency, or the gas supplier.

Disconnect gas piping from 48MA unit when leak test- ing at pressures greater than 0.5 psig. Pressures greater than 0.5 psig will cause gas valve damage resulting in a hazardous condition. If gas valve is subjected to pres- sure greater than 0.5 psig, it must be replaced. When pressure testing ®eld-supplied gas piping at pressures of

0.5psig or less, the unit connected to such piping must be isolated by manually closing the gas valve.

INSTALLATION

General Ð Install unit on rooftop, outdoor site only. In- stall unit, electrical wiring, gas supply line (48MA) and con- densate drain lines in accordance with all applicable codes.

Unit Clearances Ð See Fig. 1 and 2 for service and air¯ow clearances. For 48MA gas-®red units, provide not less than 36-in. clearance to combustibles from top and all sides. Keep burner end free from any obstruction.

Locate exit terminals of mechanical draft system (48MA ¯ue outlet) as follows:

·Not less than 12 in. from any opening through which com- bustion products could enter the building.

·Not less than 2 ft from any adjacent building.

·Not less than 7 ft above grade when unit is adjacent to public walkways.

Roof Curb Ð Assemble and install per instructions shipped with this accessory. Information required to ®eld fabricate a roof curb and other curb data are shown in Fig. 3-5.

Install ®eld-supplied insulation, cant strips, roo®ng and counter ¯ashing as required. Seal all curb joints with mastic or other suitable roof cement to keep out moisture. Be sure that run-off pan at compressor end of curb is completely flashed and sealed.

Seal strip (Fig. 3) is shipped with accessory roof curb. In- stall as described in the roof curb installation instructions. The seal strip compresses under unit weight so that an air- tight seal and vibration isolation are provided between unit base and curb.

Roof Openings Ð Except for the compressor and con- denser section, roof area under the unit need not be ®lled in as the curb-mounted unit encloses this space. Leaving this roof section open provides ample clearance for ductwork, piping, and power and control wiring.

If the roof area inside curb is to be ®lled in so that roof deck and bottom of base unit can be used as a return-air ple- num, any spaces under the curb ¯anges caused by corru- gated roo®ng or roof irregularities must be sealed to prevent water seepage. If spaces are not sealed, the negative pres- sure of return air may draw water under the unit and into the building structure.

If openings are cut in a ®nished roof, provide at least 6-in. space on each of the longer sides of the supply and return air openings. Due to interference from the roof curb structure, this additional clearance may not be possible on the short sides.

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