Advanced Specialty Gas Equipment

AC Series
Semi-Automatic Changeover Systems

AC Series changeover systems are used to connect two or more cylinders together for uninterrupted gas flow. These semi-automatic, wall-mounted manifold systems are available in either Brass or Type 316 Stainless Steel construction and are supplied with the appropriate wall mounting brackets.

The system uses two high purity diffusion resistant regulators (one connected to each bank) which act as a changeover device. Delivery pressure of regulator No. 1 is set 10–15 psi higher than regulator No. 2. This causes regulator No. 1 to flow gas while holding regulator No. 2 closed. When the gas in bank No. 1 is exhausted, regulator No. 2 will begin to flow gas. Inlet pressure gauges on the regulators indicate pressure in each manifold bank. When gas in the first cylinder bank has been exhausted and a changeover has occurred, the empty cylinders are replaced and the delivery pressure settings of the regulators are readjusted. This will cause a reverse changeover when bank No. 2 is exhausted. Because delivery pressure drops slightly when a changeover occurs, a line regulator should be installed downstream to eliminate pressure variations.
AC Series

Standard Features
  • Modular Construction allows field installation of additional stations without welding or soldering.
  • Diffusion Resistant, Diaphragm Seal Station Valves (on four cylinder or larger systems) ensure that gas purity is maintained and allow for isolation of individual cylinders on the manifold without interrupting gas flow.
  • High Purity, Diffusion Resistant Regulators minimize diffusion of air into the system, maintaining gas purity. Brass changeover systems include two Model HPD Regulators. Stainless steel changeover systems include two Model APC Regulators. Other regulators may be substituted for unique requirements, such as high delivery pressures or high flow rates. Contact your Advanced Representative for more information.
Optional Features
  • Manifold Master Shut-off Valves allow a manifold bank to be isolated from a changeover regulator.
  • Double-Braided (All Metal) 3' Stainless Steel Flexible Hose Pigtails with Stainless Steel CGA connections extend service life and provide ease of connecting cylinders.
  • Check Valves prevent discharge of gas from manifold and pigtails when changing cylinders (required for flammable gases).
  • Pressure Switches monitor line pressure and can activate an external alarm when a certain predetermined pressure is reached.

  Maximum Inlet Pressure: 3000 psig

  Delivery Pressure Range: 50–150 psig
    (For higher delivery pressures, contact your
     Advanced Representative)

  Flow Coefficient (each station valve):
    Brass Manifolds: Cv = 0.25
    Stn. Stl. Manifolds: Cv = 0.30

   Inlet Connections:
    CGA connection as specified

  Outlet Connection: 1/2" NPT female

  Brass Systems: HPD-3-150
  Stn. Stl. Systems: APC-3-150

Optional Pressure Switch

Optional Master Shut-off Valve:  SG5475 Series

Ordering Information
To order a semi-automatic changeover manifold system, complete the part number using the "Part Number Key". For example, to order a 6 cylinder,brass changeover system, with flexible pigtails, without check valves, and with CGA 350 connections, the part number would be AC-6BF-350. Order by complete part number.

Note: Two cylinder semi-automatic manifolds do not include manifold headers. Cylinders are connected directly to the regulator inlet pigtails (cylinder leads).

Manifolds for Acetylene Service require flashback arrestors (SG6545). All manifolds ordered with CGA 510 will be shipped with flashback arrestors installed on each pigtail, unless the order specifies with which gas it will be used.

Warning: Advanced does not recommend the use of stainless steel manifolds for Oxygen service and will not provide such manifolds with CGA 540 connections.


Materials of Construction
  Metal Parts: Brass or Type 316
     Stainless Steel as specified
  Seals: PTFE
    Check Valves:
      Brass Rigid Pigtails: EPDM;
      SS Flexible & Rigid Pigtails: Viton®
    Station Valves: PCTFE
  Brass Systems: Model HPD
Stn. Stl. Systems: Model APC
Optional Pressure Switch
Optional Master Shut-off Valve: SG5475 Series

Optional Equipment and Replacement Parts
Equipment and Replacement Parts Part No.
Manifold Master Shut-off Valve – Installed (2 required)  
  Brass Not Available
  Stainless Steel
Pressure Switches  
Flashback Arrestor - (Required for Acetylene Service–one per cylinder) SG6545
PTFE O-Ring Kits (package of 25 ea.)
  For connection between pigtail and
   station valve
  For header connection
    Brass Manifolds
  Stainless Steel Manifolds SG6082S
Replacement Pigtails, Rigid Type  
  Brass without Check Valves SG6640-(CGA)
  Brass with Check Valves SG6641-(CGA)
  Stainless Steel without Check Valves SG6642-(CGA)
  Stainless Steel with Check Valves SG6643-(CGA)
Replacement Pigtails, Flexible Type  
  Without Check Valves SG6638-(CGA)
  With Check Valves SG6639-(CGA)
Replacement Station Valves  
  Brass 0202-5083A
  Stainless Steel Not Available
Repair Kit for Station Valves  
  For Brass Valves 0202-3079A
  For Stainless Steel Valves 0202-3076A
Additional Stations--For adding stations to the following existing manifolds (specify left or right bank when ordering)  
  Brass with Rigid Pigtails without
     Check Valves
  Brass System with Rigid Pigtails with     Check Valves SG6661-(CGA)
  Brass System with Flexible Pigtails     without Check Valves SG6662-(CGA)
  Brass System with Flexible Pigtails     with Check Valves SG6663-(CGA)
Stn. Stl. System with Rigid Pigtails     without Check Valves SG6664-(CGA)
Stn. Stl. System with Rigid Pigtails with     Check Valves SG6665-(CGA)
Stn. Stl. System with Flexible Pigtails     without Check Valves SG6666-(CGA)
Stn. Stl. System with Flexible Pigtails     with Check Valves SG6667-(CGA)
Where "(CGA)" is indicated above, insert proper Compressed Gas Association connection number to complete the part number. Example: SG6667-580. Order by complete part number.