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113243-1 www.amdry.com 13
It is your responsibility to have ALL plumbing connections
made by a qualified professional to ensure that the gas
plumbing installation is adequate and conforms with local
and state regulations or codes.
Care must be exercised when leveling steam dryers into
final position. After leveling the dryer, check the downward
pitch of the heat exchanger from front to rear with a level.
Likewise, check the downward pitch of the return condensate
manifold toward its outlet part. Absence of these downward
pitches will result in probable water hammer and premature
heat exchanger fracture and leakage.
The presence of condensate in the steam will cause water
hammer and subsequent heat exchanger failure. The steam
supply connection must be taken from the top of a well-dripped
steam main. If the supply run-out to the dryer exceeds 20 feet
(6.1 meters), it should be dripped just before the control valve
with a proper trap and dirt pocket.
Failure to comply with the requirements
stipulated in this manual can result in component
failure, which will VOID THE WARRANTY.
The dryer is manufactured with a pneumatic
(piston) damper system, which requires an
external supply of air (80 psi +/- 10 psi [5.51
bar +/- 0.68 bar]).
Steam Coil pH Level
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.
The dryer is provided with a 1/2 N.P.T. inlet pipe connection
located at the right side of the base of the dryer. The minimum
pipe size (supply line) to the dryer is 1/2 pipe. For ease in
servicing, the gas supply line of each dryer must have its own
The size of the main gas supply line (header) will vary
depending on the distance this line travels from the gas meter
or, in the case of L.P. gas, the supply tank, other gas-operated
appliances on the same line, etc. Specific information
regarding supply line size should be determined by the gas
Undersized gas supply piping can create a low
or inconsistent pressure, which will result in
erratic operation of the burner ignition system.
Consistent gas pressure is essential at ALL gas connections.
It is recommended that a 3/4-inch (19.05 mm) pipe gas loop
be installed in the supply line servicing a bank of dryers. An
in-line pressure regulator must be installed in the gas supply
line (header) if the (natural) gas pressure exceeds 12.0
inches (29.9 mb) of water column (W.C.) pressure. (Refer to
the illustrations above.)
A water column test pressure of 3.5 inches (8.7
mb) for natural gas and 10.5 inches (26.1 mb)
for liquid propane (L.P.) dryers is required at the
gas valve pressure tap of each dryer for proper
and safe operation.
A 1/8 N.P.T. plugged tap, accessible for a test gauge
connection, must be installed in the main gas supply line
immediately upstream of each dryer.
Pipe joint compounds that resist the action of
natural gas and L.P. gas must be used.
Test ALL connections for leaks by brushing on
a soapy water solution (liquid detergent works
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
NEVER TEST FOR LEAKS WITH A FLAME!!!
The dryer must be isolated from the gas supply
piping system by closing its individual manual
shutoff valve during any pressure test of the gas
supply system at test pressures equal to or
less than 1/2 psig (3.5 kPa).