working clearance under overhead lines. Provide electric isolation between
dissimilar metals for the purpose of minimizing galvanic corrosion.
3.1.1
Packaged Terminal Air Conditioners and Heat Pumps
Wall sleeve installation shall provide a positive weathertight and airtight
seal.
3.1.2
Unitary Air Conditioning System
Install as indicated, in accordance with requirements of ASHRAE 15, and the
manufacturer's installation and operational instructions.
3.1.3
Room Air Conditioners
Install units in accordance with manufacturer's instructions. Provide
structural mountings, closures, and seals for weathertight assembly. Pitch
unit as recommended by manufacturer to ensure condensate drain to drain pan
without overflow.
3.2
PIPING
Brazing, bending, forming and assembly of refrigerant piping shall conform
to ASME B31.5.
3.2.1
Pipe Hangers and Supports
Design and fabrication of pipe hangers, supports, and welding attachments
shall conform to MSS SP-58. Installation of hanger types and supports for
bare and covered pipes shall conform to MSS SP-69 for the system
temperature range. Unless otherwise indicated, horizontal and vertical
piping attachments shall conform to MSS SP-58.
3.2.2
Refrigerant Piping
Cut pipe to measurements established at the site and work into place
without springing or forcing. Install piping with sufficient flexibility
to provide for expansion and contraction due to temperature fluctuation.
Where pipe passes through building structure pipe joints shall not be
concealed, but shall be located where they may be readily inspected.
Install piping to be insulated with sufficient clearance to permit
application of insulation. Install piping as indicated and detailed, to
avoid interference with other piping, conduit, or equipment. Except where
specifically indicated otherwise, run piping plumb and straight and
parallel to walls and ceilings. Trapping of lines will not be permitted
except where indicated. Provide sleeves of suitable size for lines passing
through building structure. Braze refrigerant piping with silver solder
complying with AWS A5.8. Inside of tubing and fittings shall be free of
flux. Clean parts to be jointed with emery cloth and keep hot until solder
has penetrated full depth of fitting and extra flux has been expelled.
Cool joints in air and remove flame marks and traces of flux. During
brazing operation, prevent oxide film from forming on inside of tubing by
slowly flowing dry nitrogen through tubing to expel air. Make provisions
to automatically return oil on halocarbon systems. Installation of piping
shall comply with ASME B31.5.
3.2.3
Returning Oil From Refrigerant System
Install refrigerant lines so that gas velocity in the evaporator suction
SECTION 15730N
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