Radium Engineering vent valves feature roll-over protection for fuel cells and gas tanks. The valves come in different varieties for all fill type applications; standard fill and quick-fill. Simply put, the larger the vent, the quicker the fuel cell can be filled. NOTE: Be sure to lubricate the FKM O-ring prior to installing either valve.
STANDARD FILL ROLL OVER VALVE
20-0934 ROLL OVER VALVE, 12AN ORB TO 8AN MALE
This roll over vent valve can be used for fuel tanks that have -12AN ORB female threads. The large external -8AN male fitting is more than enough for all standard fuel filling. The 1-piece machined part is manufactured from billet 6061 aluminum and type-II anodized. Included is 1 ball valve, FKM O-ring, and a stainless steel retaining ring.
In case of an inverted accident in which the wheels are up-ended, the ball valve sinks sealing the vent. This safely prevents fuel from leaking out of the fuel cell vent line.
NOTES:
1. The vertical height of at least one portion of the vent tubing (not included) should be positioned above the highest point of the fuel fill point.
2. The valve can easily be disassembled for cleaning, inspection, and maintenance.
3. The valve is compatible with all fuel types including alcohol fuels such as methanol and E85.
4. This roll over valve comes standard on all Radium FCST units after August 2023.
"QUICK FILL" DYNAMIC SAFETY VENT VALVES
These internal DSV valves can be used for fuel tanks that have 12AN ORB female threads (including the Radium FCST/FCST-X). The advanced tank venting and high flowing 12AN male fitting permits dry break applications that use dump cans for quick refueling. The 1-piece machined part is manufactured from billet 6061 aluminum and type-II anodized. Included are 2 ball valves, FKM O-ring, and a stainless steel retaining ring. The DSV determines when the tank is full as the upper sealing ball valve floats to the top shutting off the air (vent) source. This safely prevents fuel from traveling up and out of the fuel cell vent line. The DSV serves 2 main purposes, fuel fill shut off and roll over protection.
ROLL OVER PROTECTION
In case of an accident in which the wheels are up-ended, the the ball valve sinks sealing the vent. This safely prevents fuel from leaking out of the fuel cell vent line.
FUEL FILL SHUT OFF
Dry breaks are unique in that they seal the fill line during refueling. When the tank becomes full and the DSV valve shuts off the vent, a small amount of pressure will build in the fuel cell. This low air pressure is determined by the height of the dump can with respect to the lowest part of the fuel cell (a larger distance will result in higher head pressure). The dump can will begin to "chug". This is by design as it informs the operator that the fuel cell is full and the dry break can now be released. The residual air pressure will make its way out of the vented dry break receiver and permit the fuel level to rise slightly in the tank.
NOTES:
1. The vertical height of the top (shut-off) ball in the dynamic safety valve should be positioned lower than the highest point of the fuel fill point.
2. The vertical height of at least one portion of the vent tubing (not included) should be positioned above the highest point of the fuel fill point.
3. These internally mounted DSVs are perfect for pressureless "vented" dry break receivers such as Radium Engineering 20-0495-V, 20-0504-V, and 20-0549-V.
4. The valves can easily be disassembled for cleaning, inspection, and maintenance.
5. The valves are compatible with all fuel types including alcohol fuels such as methanol and E85.
6. These are 2 different DSVs available. Read below for important information regarding there differences.
20-0535 DSV, 12AN ORB TO 12AN MALE, LOW FILL
This long quick fill dynamic safety vent valve shuts off the refueling process early. After the DSV float valve shuts off the vent, pressure will begin to build in the fuel cell. Once the dry break is released, air pressure will bleed out of the fill vent and fuel will quickly fill the empty void in the fuel cell. 
This DSV is ideal for smaller fuel cells and/or shorter fill necks.
20-0935 DSV, 12AN ORB TO 12AN MALE, HIGH FILL
This short quick fill dynamic safety vent valve shuts off the refueling process late. After the DSV float valve shuts off the vent, pressure will begin to build in the fuel cell. Once the dry break is released, air pressure will bleed out of the fill vent and fuel will quickly fill the empty void in the fuel cell. 
This DSV is ideal for larger fuel cells and/or longer fill necks.
FUEL LEVEL ADAPTER
20-0439 12AN ORB to 5-Bolt SAE Adapter
To use a Radium Engineering DSV on an old FCST that has 8AN ORB vent threads (20-014X-XX), this adapter can be used.
However, a fuel level sender cannot be used with this adapter in place.
REMOTE FITTING
14-0434 12AN ORB TO 12AN MALE
This would be used if the external quick fill DSV needs to be remotely mounted off the fuel cell. It will secure directly into the 12AN ORB Vent Port on the Radium FCST.
Or it can be used in conjunction with 20-0439 12AN ORB to 5-Bolt SAE Adapter for older FCST units.
