2.4.5
Brazing Filler Metal
Filler metal shall conform to AWS A5.8, Type BAg-5 with AWS Type 3 flux,
except Type BCuP-5 or BCuP-6 may be used for brazing copper-to-copper
joints.
2.5
VALVES
Valves shall be designed, manufactured, and tested specifically for
refrigerant service. Valve bodies shall be of brass, bronze, steel, or
ductile iron construction. Valves 25 mm 1 inch and smaller shall have
brazed or socket welded connections. Valves larger than 25 mm 1 inch shall
have [tongue-and-groove flanged] [butt welded] end connections. Threaded
end connections shall not be used, except in pilot pressure or gauge lines
where maintenance disassembly is required and welded flanges cannot be
used. Internal parts shall be removable for inspection or replacement
without applying heat or breaking pipe connections. Valve stems exposed to
the atmosphere shall be stainless steel or corrosion resistant metal plated
carbon steel. Direction of flow shall be legibly and permanently indicated
on the valve body. Control valve inlets shall be fitted with integral or
adapted strainer or filter where recommended or required by the
manufacturer. Purge, charge and receiver valves shall be of manufacturer's
standard configuration.
2.5.1
Refrigerant Stop Valves
Valve shall be the globe or full-port ball type with a back-seating stem
especially packed for refrigerant service. Valve packing shall be
replaceable under line pressure. Valve shall be provided with a
[handwheel] [or] [wrench] operator and a seal cap. Valve shall be the
straight or angle pattern design as indicated.
2.5.2
Check Valves
Valve shall be the swing or lift type as required to provide positive
shutoff at the differential pressure indicated. Valve shall be provide
with resilient seat.
2.5.3
Liquid Solenoid Valves
Valves shall comply with ARI 760 and be suitable for continuous duty with
applied voltages 15 percent under and 5 percent over nominal rated voltage
at maximum and minimum encountered pressure and temperature service
conditions. Valves shall be direct-acting or pilot-operating type,
packless, except that packed stem, seal capped, manual lifting provisions
shall be furnished. Solenoid coils shall be moisture-proof, UL approved,
totally encapsulated or encapsulated and metal jacketed as required.
Valves shall have safe working pressure of 2760 kPa 400 psi and a maximum
operating pressure differential of at least 1375 kPa 200 psi at 85 percent
rated voltage. Valves shall have an operating pressure differential
suitable for the refrigerant used.
2.5.4
Expansion Valves
Valve shall conform to ARI 750 and ASHRAE 17. Valve shall be the diaphragm
and spring-loaded type with internal or external equalizers, and bulb and
capillary tubing. Valve shall be provided with an external superheat
adjustment along with a seal cap. Internal equalizers may be utilized
where flowing refrigerant pressure drop between outlet of the valve and
SECTION 15182
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