American Dryer Non-Tilting Phase 5 ML-200 - Manual (Page 45)

41
E. STEAM DAMPER ACTUATOR SYSTEM
The system consists of a hinged damper plate, pneumatic piston, and 24 volt solenoid valve with a needle valve to
control the speed of the piston actuation. 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 pistons. The piston rod
extends, pushing the hinged steam damper plate to the opened position. This allows room air to be drawn through
the hot steam coil and then through the tumbler (basket).
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 retract 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 tumbler (basket) for a rapid cool down.
The steam damper plate should open and close slowly and smoothly. The speed can be modulated by adjusting
the needle valve knob. Turning the knob clockwise (CW) restricts the compressed airflow and slows down the
steam damper movement. Counterclockwise (CCW) adjustment speeds up the steam damper motion. Upon
completion of adjustment, tighten the needle valve's locking nut.