American Dryer Corp. AD-202, Operation Manual, Page: 38 / 62

34 American Dryer Corp. 113289 - 6
4. Steam Damper Air System Connections
In standard format, this dryer is manufactured with a pneumatic (piston) damper system, which requires an
external supply of compressed air. (Note: this dryer may be provided with an optional steam solenoid valve
in which case, no steam damper system is provided.) The air connection is made to the steam damper
solenoid valve, which is located at the rear inner top area of the dryer, just in front of the electric service
relay box (refer to the
bottom illustration on page 35 ).
a. Air Requirements
Compressed
Air Supply
Air Pressure
Normal 80 psi 5.51 bar
Minimum Supply 70 psi
4.82 bar
Maximum Supply 90 psi
6.21 bar
Shaded areas are stated in metric equivalents
b. Air Connection
Air connection to system — 1/4” Quick Connection
c. No air regulator or filtration is provided with the dryer. External regulation/filtration of 80 psi (5.51 bar)
must be provided. It is suggested that a filter/regulator/gauge arrangement be added to the compressed
air line just before the dryer connection. This is necessary to ensure that correct and clean air pressure
is achieved.
5. Steam Damper System Operation
The dryer’s steam damper as shown in the top illustration on page 35 , allows the coil to stay constantly
charged eliminating repeated expansion and contraction. When the damper is opened, the air immediately
passes through the already hot coil, providing instant heat to start the drying process. When the damper is
closed, ambient air is drawn directly into the tumbler, allowing a rapid cool down.
Diagram 1 shows the damper in the heating (open) mode, allowing heat into the tumbler.
Diagram 2 shows the damper in the cool down (closed) mode, pulling ambient air directly into the tumbler
without passing through the coils.
NOTE: With the dryer off or with no air supply, the steam damper is in cool down mode as shown in
Diagram 2 at the top of page 35 .