B&C Technologies DI-475 Industrial User Manual
Page 31
On a call for heat, a 24-volt signal is applied to the 3-way/2-position solenoid valve. This
signal switches the valve so that compressed air is sent to the piston. The piston rod extends,
pushing the hinged steam damper plate to the open position. This allows room air to be
drawn through the hot steam coil and then through the basket (tumbler).
When the temperature set point has been reached, the 24-volt signal is removed from the
solenoid valve, so that the solenoid valve blocks the air supply to the piston and the air in the
piston is bled to the atmosphere. The spring in the piston now retracts the piston rod, closing
the steam damper. The steam damper plate now covers the steam coil and allows room air to
bypass the coil before entering the basket (tumbler) For a rapid cool down.
The steam damper plate should open and close slowly and smoothly. This speed can be
modulated by adjusting the needle valve knob. Turning the knob clockwise restricts the
compressed airflow and slows down the steam damper movement. counterclockwise
adjustment speeds up the steam damper motion. Upon completion of adjustment, tighten the
needle valve’s locking nut.