American Dryer Corp. Gas- DSI/Steam ML-82 II - Manual (Page 31)

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b. The steam supply piping to the dryer must include a 12-inch (30.48 cm) riser along with a drip trap and
check valve. This will prevent any condensate from entering the steam coil.
c. Flexible hoses or couplings must be used. The dryer vibrates slightly when it runs and this will cause the
steam coil connections to crack if they are hard piped to the supply and return mains.
d. Shutoff valves for each dryer should be installed in the supply, return, and drip trap return lines. This
will allow the dryer to be isolated from the supply and return mains if the dryer needs maintenance work.
e. Install an inverted bucket steam trap and check valve for each unit at least 12-inches (30.48 cm) below
steam coil as close to the coil as possible.
1) A trap with a capacity of 1,000 pounds (454 kg) of condensate per hour at 125 PSI (8.62 bars) is
needed for each unit.
f. A 3/4-inch (19.05 mm) vacuum breaker should be installed for each unit in the piping. This will prevent
the condensing steam from causing a vacuum inside the coil and possibly damaging the coil.
g. The supply and return lines should be insulated. This will save energy and provide for the safety of the
operator and maintenance personnel.
h. Water pockets in the supply line, caused by low points, will provide wet steam to the coil possibly causing
coil damage. ALL horizontal runs of steam supply piping should be pitched 1/4-inch (6.35 mm) for
every 1 foot (0.30 meters) back toward the steam supply header causing any condensate in the line to
drain to the header. Install a bypass trap in any low point to eliminate wet steam.
IMPORTANT: Flexible hose and couplings must be used. Coil failure due to hard plumbing
connections will VOID THE WARRANTY.