Oil-Air Ratio Regulators are used to proportion fuel flows to modulating oil burners. Combustion air flows produce a proportional pressure signal that is applied to the regulator to set the outlet oil pressure. On initial adjustment the desired oil flow rate is set to match the burner air capacities. The regulator holds this oil to air ratio at all firing rates. Pressure balancing of the oil control system eliminates complicated valve linkages on these burners. Heat input turndown over a 10 to 1 range is achieved by varying the position of the combustion air control valve. This simple single valve control is readily interlocked with control motors to process temperature, pressure or other functions to provide precisely the heat required at any time. Oil-Air Ratio Regulators have a unique balanced valve design for inlet oil pressure in the 40 psig to 100 psig range. A constant oil pressure is required at the OAR inlet. FEATURES   Precise control of outlet pressure Pressure balance system for single valve control 10:1 turndown ranges 40 to 100 psig inlet oil pressures 250°F Maximum Operating Temperature Balanced valve design Accurate 30:1 oil to air pressure ratio at all firing rates Adjustable low fire setting Designed for continuous service Rugged, heavy-duty construction   CAPACITY TABLE Model Number G.P.H. Inlet Pressure Min. (psig) Max. (psig) 4 OAR 50 3/4 to 50 45 90 6 OAR 100 2 to 100 45 90