AT&T D-320 Clothes Dryer User Manual


 
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In keeping with good compressed air piping design, the air dryer should be installed on the downstream side of the
air receiver and aftercooler. An AIR/TAK prefilter(s) for oil and dirt removal installed at the inlet of the dryer is
recommended. Contamination can be present in a compressed air system and can reduce the ability of the dryer
heat exchangers to achieve the proper heat transfer. AIR/TAK recommends the use of afterfilter(s) to remove final
trace contaminates.
All water cooled dryers are factory piped for cooling tower water, unless ordered otherwise. A dryer that is piped for
city water cannot be used on cooling tower water without necessary piping changes because of: the higher water
temperature, lower water pressure and the increased water flow needed. All water cooled dryers are supplied with
a factory mounted automatic water regulating valve which is designed to maintain the proper working refrigerant
head pressure under all dryer load conditions. No adjustment will be necessary. (Full water pressure and flow
should be supplied to the water line inlet. Refer to Section L for water cooled water requirements.)
All dryers are supplied with automatic drain valves. On models D-320 to D-2000, an isolation valve/strainer and
solenoid drain valve is provided for the outlet of the air to-refrigerant heat exchanger. Models D-2500 to D-7500
dryers are supplied with two drain outlets with zero air loss valve provided for each outlet. Models D-8000 and
larger are supplied with four drain outlets and two zero air loss drain valves. Solenoid drain valves with isolation
valve/strainer and zero air loss drain valves are to be installed at destination.
F. ELECTRICAL
The dryer is completely wired at the factory. A terminal box at the rear of the dryer, or a control box on the side of
the dryer is provided for the main power connection. Power connections can be made through any knock-out on
the terminal box or through the side or top of the control box. The dryer dataplate must be checked to verify
voltage, phase and cycle. Connect the power leads to the terminal block which is conveniently located within the
box. Always be sure adequate power is available to maintain efficient operation of your dryer.
A properly sized fused main disconnect switch (supplied by the installer) must be located near the dryer. Check the
wiring diagram supplied with the dryer for the recommended fuse size. The use of fusetron time-delay fuses will
permit smaller fuse sizes and, in some instances, a smaller fused disconnect switch may be used.
The dryer wiring must be independent of the air compressor so as not to cycle along with the air compressor.
Fan rotation must be checked to assure proper air flow. Air must be drawn through the finned condenser and exit
through the fan guard. To change fan rotation, switch any two hot power leads on the terminal block located in the
box.
Dryers with scroll compressor(s) need to be checked for proper rotation by making sure the discharge pressure is
greater than the suction pressure. To change rotation, switch inlet power leads L1 and L3. If you have any question
or problems, please consult factory.
Dryers with pre-wired solenoid drain valves need to have the DIN connector attached to the drain valve after the
drain is installed on the dryer.
On units supplied with crankcase heaters, the crankcase heaters are pre-wired at the factory to be energized when
power is supplied to the dryer. It is important that the crankcase heaters be energized at least 24 hours before
initial start-up or after prolonged shut-down. (See Start-Up).