Selecting the Proper AutoFlow Valve

Use the specification below as your guide.

A. Manufacturers:

  1. Flow Design, Inc., AutoFlow or approved equal. Models YR, AC, AB, WG, WS, WB, WR or WT.

B. Design:

  1. The GPM for the automatic flow control valves shall be factory set and shall automatically limit the rate of flow to within five percent of the specified GPM over at least 95 percent of the control range.
  2. For 1/2″-2″, the flow cartridge shall be removable from the Y-body housing without the use of special tools to provide access for regulator changeout, inspection and cleaning without breaking the main piping. (Access shall be similar to that provided for removal of a Y-strainer screen).
  3. Pump Head Requirement – The permanent pressure loss added to the pump head shall not exceed seven feet.
  4. Each valve shall have two SuperSeal pressure/temperature test ports.
  5. All automatic flow control devices shall be supplied by a single source and certified flow tests, witnessed by a professional engineer, shall be available.
  6. Five-year product warranty and first year cartridge exchange, up to ten percent.

C. Construction:

  1. The internal wear surfaces of the valve cartridge must be stainless steel.
  2. The internal flow cartridge body shall have machined threads so the spring free height may be compensated for without the use of fixed shims. A crimped sheet metal design is not acceptable.
  3. The internal flow cartridge shall be permanently marked with the GPM and spring range.
  4. For 1/2″ through 2″ pipe sizes: An assembly shall consist of a brass Y-type body, integral brass body ball valve and O-ring type union.; Flow Design Model AC or equal.
  5. For 2 1/2″ and larger flanged connections: Ductile iron body suitable for mounting wafer style between standard 150# or 300# flanges. The long flange bolts and nuts shall be provided with each control valve. Flow Design Model WS or equal.
  6. All valves shall be factory leak tested at 100 psi air under water.

D. Minimum ratings:

  1. 1/2″ through 2″ pipe size: 400 PSIG at 250°F
  2. 2 1/2″ through 14″ pipe size: 600 PSIG at 250°F
  3. 16″ through 30″ pipe size: 250 PSIG at 250°F

E. Flow Verification (choose one):

  1. The differential pressure across the Automatic Flow Control Valve shall be measured for flow verification and to determine the amount of system over heading or under pumping.
  2. The flow shall be verified by measuring the differential pressure across the coil served or the wide-open temperature control valve and calculating the flow using the coil or valve Cv.
  3. A Venturi shall be installed on the supply side of the coil to verify flow.

F. Test Kit:

A differential pressure test kit shall be supplied to verify flow and measure overheading. The kit shall consist of a 4 1/2″ diaphragm gauge equipped with ten foot hoses and P/T adapters all housed in a vinyl case. Calibration shall be 0-35 PSID for 2-32 PSI spring range or 0-65 PSID for 5-60 PSI range.

G. Installation:

  1. Install automatic flow control valves on the return lines of coils as indicated on the plans. A balancing valve on supply side is not acceptable.
  2. The standard ports and handles shall clear 1″ thick insulation. Handle and port extensions are required for over 1″ thick insulation. Do not insulate flow control valves used on heating coils.
  3. Install, on the supply side of coils, a Y-strainer (40 mesh, 2 GPM or less; 20 mesh, above 2 GPM) with brass blowdown valve with 3/4″ hose end connection with cap. Inline (basket) strainer is not acceptable.