Vulcan-Hart VL Series Service Manual page 42

VL BOILER BASE SERIES CONVECTION STEAMERS - SERVICE PROCEDURES AND ADJUSTMENTS
inlet valve is open and the exhaust valve closed when
the steam control arm handle is pulled forward and
reverses when the control arm is released.
NOTE: In the event of an electrical component or a
power failure, the steam control arm can be operated
manually on automatic models.
F24650 Rev. A (1017) Page 42 of 93