4-36.7. PACKLESS VALVE - AIR CONDITIONING - MAINTENANCE INSTRUCTIONS.
a. Take packless valves apart only if inspection or replacement of internal parts is necessary. When
reassembling valve, before inserting diaphragms in bonnet, be sure handwheel is in wide open position. Turn
handwheel countercockwise until stem backseats. If handwheel is in closed position, diaphragms will not
anchor properly in bonnet and proper seal will not be established when assembling bonnet to body.
b. The packless valve diaphragm and composition seat disc in lower stem can be damaged by excessive
heat. To protect the internal parts of the valve, the installation and brazing instructions given below must be
carefully carried out. Time is a very important factor: The time that heat is being applied must be a matter of
seconds, not minutes.
(1) Open valve wide. Turn handwheel counterclockwise until stem backseats.
(2) Turn handwheel back about 1/4-turn. This will move lower stem holding seat disc to position shown.
This minimizes danger of heat being transfered to valve seat.
(3) Thoroughly clean end of tubing and socket connection on valve body.
(4) Apply a thin coat of properly mixed, high quality, non- corrosive flux to end of tubing and valve body
(5) Insert tubing into valve socket until it is tightly seated against shoulder.