Combustion 911
Supplying and Serving the Combustion Industry
an Olsträd Engineering Company

Site Search

Limiting Orifice Valve Manual Gas Adjuster GAFLimiting Orifice Valve Manual Gas Adjuster GAF

GAF gas adjusters are designed to provide accurate flow control. The conical needle or cylindrical plug valve has a micrometric adjusting stem, allowing excellent regulation capabilities even at reduced flows. A common screwdriver is used to perform adjustments with the GAF; no special tools are needed. A seal cap protects the adjustment screw and prevents leakage.

  • Sizes: ½” to 4”
  • Viton seal
  • Max. pressure = 5 PSI
  • Min. fluid temperature = -20°F
  • Max. fluid temperature = 360°F


  • Micrometric flow regulation for non-aggressive gases (i.e. natural gas, LPG, air, nitrogen, etc.)


Installation and Regulation Notes

  • It is recommended to mount the GAF downstream of the measuring orifice.
  • Check that the GAF’s valve seat is free of foreign material prior to installation. If necessary, purge GAF with compressed air.
  • Disassemble GAF’s connection flanges (inlet/outlet) and install on the pipeline. Reassemble the connection flanges. Check for proper tightness of the gaskets.
  • Verify the pressure taps are closed and tight.

Flow rate regulation is controlled by manipulating the valve stem. Remove the plug cap and adjust the stem position using a common screwdriver.

  • Extract the stem to increase the flow rate.
  • Insert the stem to decrease the flow rate.

The GAF’s stem is fitted with positioners for maximum open/close positioning.

Ordering Information

Model and Description Model Inlet Outlet Connection Price Cart
Model 4GAF6
Inlet: ½"; Outlet: ¾"; Connection: NPT
4GAF6 ½" ¾" NPT
Model 6GAF6
Inlet: ¾"; Outlet: ¾"; Connection: NPT
6GAF6 ¾" ¾" NPT
Model 6GAF8
Inlet: ¾"; Outlet: 1"; Connection: NPT
6GAF8 ¾" 1" NPT
Model 8GAF8
Inlet: 1"; Outlet: 1"; Connection: NPT
8GAF8 1" 1" NPT
Model 10GAF10
Inlet: 1¼"; Outlet: 1¼"; Connection: NPT
10GAF10 1¼" 1¼" NPT
Model 10GAF12
Inlet: 1¼"; Outlet: 1½"; Connection: NPT
10GAF12 1¼" 1½" NPT
Model 12GAF12
Inlet: 1½"; Outlet: 1½"; Connection: NPT
12GAF12 1½" 1½" NPT
Model 12GAF16
Inlet: 1½"; Outlet: 2"; Connection: NPT
12GAF16 1½" 2" NPT
Model 16GAF16
Inlet: 2"; Outlet: 2"; Connection: NPT
16GAF16 2" 2" NPT
Model 16GAF20
Inlet: 2"; Outlet: 2½"; Connection: ANSI (Weld)
16GAF20 2" 2½" ANSI (Weld)
Model 20GAF20
Inlet: 2½"; Outlet: 2½"; Connection: ANSI (Weld)
20GAF20 2½" 2½" ANSI (Weld)
Model 20GAF24
Inlet: 2½"; Outlet: 3"; Connection: ANSI (Weld)
20GAF24 2½" 3" ANSI (Weld)
Model 24GAF24
Inlet: 3"; Outlet: 3"; Connection: ANSI (Weld)
24GAF24 3" 3" ANSI (Weld)
Model 24GAF32
Inlet: 3"; Outlet: 4"; Connection: ANSI (Weld)
24GAF32 3" 4" ANSI (Weld)
Model 32GAF32
Inlet: 4"; Outlet: 4"; Connection: ANSI (Weld)
32GAF32 4" 4" ANSI (Weld)


Combustion 911 Blog Blog Home   Combustion 911 RSS Feed RSS feed