Practical Pointers | Fives North American

OIL AND DUAL FUEL SYSTEMS

operator open (close for maintenance only)

16 osi (1 psi)

air

3D

5D

limiting orifice high fire ratio adj. (set first)

low fire ratio adjustment (set second)

16 osi

vent

not over 6" below burner (never above)

CL

oil 25 to 30 psi

about 10 psi plus spring setting

RATIOTROL and OIL BURNER

An air/oil Ratiotrol causes its oil outlet pressure (2nd column, below) to vary in proportion to the impulse or main air pressure. This automatically maintains a constant ratio of oil flow to air flow at all firing rates. The Ratiotrol spring can be adjusted to give added oil pressure and oil flow to match the atomizing air. The pressure (column 3) is constant.

Oil Outlet Pressure

Spring Total Outlet

Impulse

from Impulse

Setting

Pressure

16 osi

10 psi

2 psi

12 psi

8 4 0

5

2 2 2

7

2.5

4.5

0

2

If the combustion chamber has pressure or suction, connect the Ratiotrol's vent to the burner mounting by line (A). Use the pressure drop between supply line and combustion chamber to select Ratiotrol size and figure atomizing air pressure.

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