Dexter Laundry T-80 (Commercial) - Manual (Page 5)

3. MAKE-UP AIR. Adequate make-up air (1200 CFM) must be supplied to replace air exhausted by dryers on all
types of installations. Provide a minimum of 1.25 square foot make-up air opening to the outside for each dryer. This
is a net requirement of effective area. Screens, grills or louvers, which will restrict the flow of air, must be considered.
Consult the supplier to determine the free area equivalent for the grill being used.
The source of make-up air should be located sufficiently away from the dryers to allow an even airflow to the air
intakes of all dryers. Multiple openings should be provided.
NOTE: The following considerations must be observed for gas dryer installations where dry cleaners are
installed. The sources of all make-up air and room ventilation air movement to all dryers must be located
away from any dry cleaners. This is necessary so that solvent vapors will not be drawn into the dryer inlet
ducts. Dry cleaner solvent vapors will decompose in contact with an open flame such as the gas flame
present in clothes dryers. The decomposition products are highly corrosive and will cause damage to the
dryer(s), ducts and clothes loads.
4. ELECTRICAL REQUIREMENTS. (Refer to schematic and wiring diagram). This dryer is equipped with a
reconnectable motor and control transformer for use on 208–240V–1PH–60Hz or 110–125V–1PH–60Hz. The control
voltage is 24V, 60 Hz. The electrical power requirements necessary to operate the unit satisfactorily are listed on the
serial plate located on the back panel of each dryer. The electrical connection should be made to the terminal in the
control box on the rear of the unit, using a wire size adequate to handle the amperage and voltage listed on the serial
plate, but never smaller than No.12 AWG wire. The ground lug must be connected to a good external ground.
Individual circuit breakers for each unit are recommended. The schematic and wiring diagram is located on the
belt guard on the back of the machine.
5. GAS REQUIREMENTS. The complete gas requirements necessary to operate the dryer satisfactorily are listed
on the serial plate located on the back panel of the dryer.
The inlet gas connection to the unit is 1/2-inch pipe thread. However, the size of the piping to supply the dryer should
be determined by reference to the National Fuel Gas Code ANSI Z223.1A and consultation with the local gas supplier.
A joint compound resistant to the action of liquefied petroleum gases should be employed in making pipe
connections.
A drip tee should be provided in the gas piping entering the unit to catch dirt and other foreign articles.
All pipe connections should be checked for leakage with soap solution. Never check with an open flame.
For altitudes above 2,000 feet (610m) it is necessary to derate the BTU input. Contact your local distributor for
instructions.
L.P. gas conversion kits are available for this dryer. Contact your local distributor.
6. PRESSURE TESTING. The dryer and its individual shutoff valve must be disconnected from the gas supply
piping system during any pressure testing of that system at test pressures in excess of 1/2 psig.
The dryer must be isolated from the gas supply piping system by closing its individual manual shutoff valve during
any pressure testing of the gas supply piping system at test pressures equal to or less than 1/2 psig.
7. EXHAUST INSTALLATION. (Refer to Figure 2 at the end of section 7.) Exhausting of the dryer(s) should be
planned and constructed so that no air restrictions occur. Any restriction due to pipe size or type of installation can
cause slow drying time, excessive heat, and lint in the room.
From an operational standpoint, incorrect or inadequate exhausting can cause a cycling of the high limit thermostat,
which shuts off the main burners and results in inefficient drying.
Individual exhausting of the dryers is recommended. All heat, moisture, and lint should be exhausted outside by
attaching a pipe of the proper diameter to the dryer adapter collar and extending it out through an outside wall. This
pipe must be very smooth on the inside, as rough surfaces tend to collect lint, which will eventually clog the duct and
prevent the dryer from exhausting properly. All elbows must be smooth on the inside. All joints must be made so the
exhaust end of one pipe is inside the next one downstream. The addition of an exhaust pipe tends to reduce the amount
of air the blower can exhaust. This does not affect the dryer operation if held within practical limits. For the most
efficient operation, it is recommended that no more than 20 feet (6m) of straight 8" diameter pipe be used with two
right angle elbows. When more than two elbows are used, two feet of straight pipe should be removed for each
additional elbow. No more than four right angle elbows should be used to exhaust a dryer.
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