Anti-Syphon valves are required by various fire protection codes to be installed in fuel oil systems to prevent syphoning oil out of a tank due to a low line break or leak in the pipe.
The Anti-Syphon Valve is installed in a vertical position at the highest point in the suction line with no part of the line between the valve and the tank below the maximum oil storage level. Although suitable for outdoor installation, consideration should be given to the possibility that moisture en trained in the oil might freeze in the valve and immobilize the poppet. Complete instructions are furnished with each valve.
The Model A Anti-Syphon Valve reduces fire hazards and prevents oil spills caused by oil being siphoned from the storage tank onto the boiler room floor. The valve automatically shuts off the oil flow in the event of a broken or inadvertently left open oil suction line. This protection is required by many codes and is recommended on all installations where the highest level of oil in storage is above the boiler room floor.
The assembly consists of a heavy bronze body with oil proof gasketing, spring loaded poppet, composition seat and dashpot. Tight shutoff is assured by the resilient seat material. Smooth, quiet operation is provided by the dashpot. For positive action, the valve is furnished for various hydrostatic heads: up to 5', 5-10', 10-15', and 15-20' (as measured vertically from the top of the tank to the pump inlet). Suction lines may be tested for tightness under reasonable pressure without damage to the seat. Maximum oil grades for these valves are as follows: ⅜" and ½" valves for No. 2 oil only, ¾" for No. 2 or No. 4 oil only and the 1" through 3" for all grades of fuel oil including #6.
The Anti-Syphon Valve is installed in a vertical position at the highest point in the suction line with no part of the line between the valve and the tank below the maximum oil storage level. Although suitable for outdoor installation, consideration should be given to the possibility that moisture entrained in the oil might freeze in the valve and immobilize the poppet. Complete instructions are furnished with each valve.
Operation: In the non-flow mode, spring pressure holds the valve poppet closed against the hydrostatic head. When flow is required, an additional vacuum is created by the oil pump, lifting the poppet and opening the valve. Since the total downstream pressure of the hydrostatic head plus the pump suction is required to lift and hold open the poppet, an opening in the suction line will dissipate the vacuum, close the valve and prevent an oil siphoning effect. Valve closure will be positive regardless of whether or not the pump is in operation.
Approvals: UL Listed, New York City Board of Standards and Appeals (Cal. No. 192-34-SA)