450412-4 www.amdry.com 7
Gas Burner Assembly
Gas heated dryers are equipped with a gas burner assembly
consisting of 3 burner tubes, a gas valve, an ignitor, a flame
sensor, a sail switch, a hi-limit thermostat, and an ignition
control module. The inlet piping enters through the rear of
the dryer on the left-hand side (viewing from the front) and
runs to the front of the dryer where the gas valve is located.
NOTE: With the dryer off or no air supply to the damper
piston, the damper is in the cool down mode.
Steam Coil pH Level
NOTE: The normal pH level for copper type steam coils
must be maintained between a value of 8.5 to 9.5. For
steel type steam coils the pH level must be maintained
between a value of 9.5 to 10.5. These limits are set to
limit the acid attack of the steam coils.
IMPORTANT: Coil failure due to improper pH level will
void the warranty.
Steam Damper Actuator System
The steam damper actuator system consists of a hinged
damper plate, pneumatic piston, and a 24 volt solenoid
valve with a needle valve to control the speed of the piston
actuation.
Drive Motor
The T.E.F.C. drive motor is located in the rear right corner
(viewing from front) behind the front panel of the dryer. It
sits on an adjustable base so the motor can be easily
adjusted to the left or right, up or down, forward or backward.
Reversing Relay Panel
Lifting the control door will reveal the reversing relay box.
Located on the back of the relay box is the reversing relay
panel. Included on this panel is a 4-position terminal block,
blower overload, blower contactor, reversing contactor, 24
VAC transformer, fuse or circuit breaker, ground lug, and
possibly an arc suppressor board.
Steam Coil and Damper System
The steam coil is constantly charged, thereby eliminating
repeated expansion and contraction and also provide
instant heating to start the drying process. The steam
damper, located on top of the steam coil, is the only
temperature controlling device in this system. When the
steam damper is open, ambient air is drawn through the
coil providing heat to the dryer. When the steam damper is
closed, ambient air is drawn directly into the tumbler,
bypassing the coil, allowing a rapid cool down.