L.B. White 100 Tradesman Portable Forced Air - Manual (Page 11)

HEAT ADJUSTMENT VALVE
MAXIMUM
HEAT
MINIMUM
HEAT
1. This heater has a heat adjustment valve for varying
heat output located on the side of the heater. See
Fig.4. THIS IS NOT A MANUAL GAS SHUT OFF VALVE.
FIG. 4
2. The valve can be adjusted to deliver either minimum
heat or maximum heat. When the valve handle is
parallel to the gas flow, the valve is completely open
to deliver maximum heat output. See Fig. 5.
3. The throttle valve may be adjusted to minimum heat
output by turning the handle 90° to gas flow or any
position between maximum and minimum settings.
See Fig. 5.
FIG. 5
Variable Heat Output
10