Carrier 48MA/50ME016-040 Installation, Start-up And Service Instructions Manual

Contents

Carrier 48MA/50ME016-040 Installation, Start-up And Service Instructions Manual Manual pdf 2 page image

SAFETY CONSIDERATIONSInstallation and servicing of air-conditioning equipmentcan be hazardous due to system pressure and electrical com-ponents. Only trained and qualified service personnel shouldinstall, repair, or service air-conditioning equipment.Untrained personnel can perform basic maintenance func-tions of cleaning coils and filters and replacing filters. Allother operations should be performed by trained service per-sonnel. When working on air-conditioning equipment, ob-serve precautions in the literature, tags and labels attachedto the unit, and other safety precautions that may apply.Follow all safety codes, including ANSI (AmericanNational Standards Institute) Z223.1. Wear safety glasses andwork gloves. Use quenching cloth for unbrazing operations.Have fire extinguisher available for all brazing operations.Before performing service or maintenance operations onunit, turn off main power switch to unit. Electrical shockcould 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’sphone. Follow the gas supplier’s instructions. If you can-not reach your gas supplier, call the fire department.Do not store or use gasoline or other flammable vaporsand liquids in the vicinity of the 48MA unit or any othergas-fired appliance.Improper installation, adjustment, alteration, service, ormaintenance can cause injury or property damage. Re-fer to this manual. For assistance or additional infor-mation, consult a qualified installer, service agency, orthe gas supplier.Disconnect gas piping from 48MA unit when leak test-ing at pressures greater than 0.5 psig. Pressures greaterthan 0.5 psig will cause gas valve damage resulting ina hazardous condition. If gas valve is subjected to pres-sure greater than 0.5 psig, it must be replaced. Whenpressure testing field-supplied gas piping at pressures of0.5 psig or less, the unit connected to such piping mustbe isolated by manually closing the gas valve.INSTALLATIONGeneral — 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 — See Fig. 1 and 2 for service andairflow clearances. For 48MA gas-fired units, provide notless than 36-in. clearance to combustibles from top and allsides. Keep burner end free from any obstruction.Locate exit terminals of mechanical draft system (48MAflue 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 topublic walkways.Roof Curb — Assemble and install per instructions shippedwith this accessory. Information required to field fabricate aroof curb and other curb data are shown in Fig. 3-5.Install field-supplied insulation, cant strips, roofing andcounter flashing as required. Seal all curb joints with masticor other suitable roof cement to keep out moisture. Be surethat run-off pan at compressor end of curb is completely flashedand 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 unitbase and curb.Roof Openings — Except for the compressor and con-denser section, roof area under the unit need not be filled inas the curb-mounted unit encloses this space. Leaving thisroof section open provides ample clearance for ductwork,piping, and power and control wiring.If the roof area inside curb is to be filled in so that roofdeck and bottom of base unit can be used as a return-air ple-num, any spaces under the curb flanges caused by corru-gated roofing or roof irregularities must be sealed to preventwater seepage. If spaces are not sealed, the negative pres-sure of return air may draw water under the unit and into thebuilding structure.If openings are cut in a finished roof, provide at least 6-in.space on each of the longer sides of the supply and return airopenings. Due to interference from the roof curb structure,this additional clearance may not be possible on the shortsides.2