9
STEAM DISTRIBUTOR PIPE INSTALL
EACH CYLINDER REQUIRES SEPARATE STEAM HOSE,
CONDENSATE RETURN LINE, AND STEAM DISTRIBUTOR
PIPE.
1. The steam distributor pipe must be mounted on a plumb
surface and inclined upward. This is required so the
condensate which forms in the distributor pipe will drain to the
return line and back to the unit, or to a common drain.
2. Insert distributor pipe into duct and secure with four sheet
metal screws (not included).
3. Special distributor pipes are shipped with specific instructions
on how to mount them.
4. If the optional fan distribution unit is to be used, follow the
instructions included with the unit.
CONNECT THE STEAM HOSE
COPPER OR BRASS TUBE IS THE ONLY ACCEPTABLE
SUBSTITUTE FOR CARNES STEAM HOSE OR CONDENSATE
HOSE.
1. The steam hose should be installed so there is a continuous
rise from the humidifier to the distributor pipe. Support the
steam hose at intermediate points to prevent dips, pockets,
sags, or horizontal runs.
See Figure I
.
2. Any turns should have a minimum radius of 8” to prevent the
hose from kinking. Fasten the steam hose to the distributor
pipe with one of the hose clamps provided.
3. Push the steam hose through the opening on the top of the
humidifier cabinet and slip it over the outlet stub on the top of
the cylinder. Fasten with the hose clamp provided.
4. If long lengths of steam hose or hard tubing are used, the
use of periodic “T’s” to drain condensate should be used.
See Figure D
.
CONDENSATE RETURN LINE
1. Fasten the condensate return line to the distributor pipe with
the hose clamp provided.
2. Follow the steam hose to the humidifier cabinet and secure
the return line to the steam hose.
3. Connect the return line to the condensate return inlet with a
hose clamp provided.
4. If it is impossible to maintain a drop to the top of the cabinet,
it is necessary to run the condensate return line directly to the
air gap drain fitting or some other drain.
5. A trap of sufficient size may be necessary to prevent loss of
steam through the return line and reduce the temperature of
condensate water to the common drain. Do not install a trap if
condensate is returned to the top of the cabinet.
STEAM DISPERSION CRITERIA
1. Distributor pipe location must be at a minimum of 6 feet
upstream from any elbows, splits, coils, turning vanes, grilles,
diffusers, etc.
2. If duct temperature is 60°F or less, 10 feet is recommended.
3. Under normal conditions, most absorption distances will be
approximately 4 to 5 feet.
4. If distance recommended is not possible, then a drain pan
may be required.
5. If the air in the duct cannot accommodate the steam output,
the only recourse may be to lower the maximum output of the
unit.
6. If shorter absorption distances are required, 3 feet or less,
multiple distributor pipes could be used. Two pipes split off
one steam hose or two pipes from a dual cylinder unit.
7. If even shorter absorption distances are required, 2 feet
or less, then multi tube short absorption manifolds may be
required.
It is important to keep in mind that there are a lot of variables
involved in proper steam distribution and absorption distances
such as duct length downstream from the dispersion method,
required absorption distance determined by design, capacity of
humidification, velocity of air flow, temperature of air flow, location
of humidifiers, distance between humidifiers to distribution point,
and so on. Proper planning is a prerequisite to good performance.
It is very important that both the steam hose and condensate
return line, whether flexible or hard tubing, be installed so
there are no sags, low points, dips, or horizontal runs.
The
steam is at a very low pressure and it cannot overcome any
resistance caused by accumulating water standing in the steam
hose. Accumulation in the condensate return hose will hamper the
flow and may cause water to back up into the duct.
If it is difficult to install the steam hose to prevent sags, it is
recommended that a copper tube be used as a substitute. If a
copper tube is used, a minimum of one inch of insulation must be
applied to prevent excessive condensation (See
Figure
J
). A short
length of steam hose must be used to connect the cylinder in the
humidifier to the copper tube and another short length to connect
the copper tube to the distributor pipe. Size 3/4” copper tube (with
7/8” steam hose) can be used with steam cylinders having output
rates up to 30 pounds per hour. Size 1-1/2” copper tube (with
1-5/8” steam hose) should be used with steam cylinders having
output rates over 30 pounds per hour.
Hose lengths of no longer then 10-20 feet and proper inclines or
routing, as expressed in this manual, will provide the best chance
of having a proper operating humidifier with efficient and effective
steam dispersion.
Figure I
Note:
Over time and extended
heat, the situations described
in the previous paragraph
can occur. That’s why it is
important to perform monthly
visual inspections to maintain
and correct, improper routing of
steam and condensate lines.
Exaggerated for emphasis.
Figure J
1” Minimum Pipe Insulation
Steam Pipe
