Chapter 7
Fuel Valves & Accessories
National Oilheat Research Alliance 31
There are a number of valves and accessories
that are available for use on heating systems.
This chapter briefly examines the most
common components likely to be encountered
in the field, including:
• Oil safety valves/pressure
reducing valves
• Anti-siphon valves
• Check valves
• Foot valves
• Thermal shut off (fusible) valves
• Solenoid fuel valve
• Fuel de-aerators
• Nozzle line heaters
Oil Safety & Pressure Reducing Valves
Oil safety valves (OSV), such as the Suntec
PRV38, the Webster OSV and the Oventrop
Oilstop F are designed to:
• Prevent the flow of oil in the event a leak
occurs in the oil line between the OSV
and the burner
• Prevent excess pressure on the inlet and
seal of the fuel unit on systems with
pressurized supply lines
These valves require a sustained vacuum
on the outlet side of the valve for fuel to flow,
any leak (fitting, line, filter, etc.) that prevents
vacuum from being exerted on the outlet of the
valve will prevent the flow of oil.
On those systems with a booster or supply
pump, the valve also operates as a pressure
reducer, with supply line pressure on the inlet
side of the valve and fuel unit vacuum on the
outlet port.
Location, orientation and height of the valve
in relation to the fuel unit and/or lowest point
in the fuel line varies by manufacturer. Always
refer to the manufacturer’s instructions for
specific information.
NORA recommends that the use
of an OSV be considered on
AST installations.
Manufacturers’ instructions can be found at
these websites:
Suntec: suntecpumps.com
Webster: websterfuelpumps.com
Oventrop: oventrop.co.uk