American Dryer Corp MLS-460 manual Safety Devices

A valve can easily be checked for internal or external piloting by removing the two (2) screws which hold the solenoid operator onto the valve. For an internal pilot air to be supplied to the valve spool. For an external pilot, the solid sealing disc must be positioned on top of the internal port.

5.Loading Doors and Heat Reclaimer, Cool Down and Intake Air Damper

These solenoid valves are located in the 6-station manifold block on the pneumatic control panel. Each door piston is controlled by two (2) 2-port/2-position solenoid valve. The heat reclaimer is controlled by one (1) 2-port/2-position solenoid valves.

The three (3) pistons that control the heat reclaimer damper, cool down damper, and intake air damper are controlled by a single 3-way double acting solenoid valve.

To open the front loading door, a 120 volt signal is applied to “S1,” the coil of the valve that supplies air to the LOAD door or the heat reclaimer’s bottom port. The valve will open, and 80 PSI (552 kPa) of air is supplied to the bottom port of the piston. The piston rod will extend, and the door will open. No voltage is applied to “S2,” the coil of the valve that controls the air supply to the door pistons top port so that this line is bled to the atmosphere.

To close the front loading door or heat reclaimer damper, the voltage signals are reversed, and the loading door will close.

D. SAFETY DEVICES

The MLS-460 dryer is equipped with numerous safety devices to ensure that the dryer operates safely. The chart on the following page (page 39) lists each device with it’s location, function, computer display message, and result of tripping.

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