CARNES HBGH Installation, Operation And Maintenance Manual page 8

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 enter the duct work by way of back up in distributor pipe.
Figure H
Exaggerated for emphasis.
Figure I
Steam Pipe
If it is difficult to install the steam hose to prevent sags, it is
recommended that copper tube be used as a substitute. If copper
tube is used, a minimum of one inch of insulation must be applied
to prevent excessive condensation (See Figure I). A short length
of steam hose must be used to connect the cylinder in the humid-
ifier 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. Length restrictions shown
in the Maximum Steam Hose Length Table also apply to installa-
tions where copper tube is used and any use of 90° elbows add
approximately three feet of equivalent length, thus negatively
affecting loss of capacity, efficiency and effectiveness.
Hose lengths of no longer then 10-20 ft. and proper inclines or
routing, as expressed in this manual, will provide the best chance
of having a proper operating humidifier and efficient and effective
steam dispersion.
INSTALL STEAM DISTRIBUTOR PIPE
EACH CYLINDER REQUIRES SEPARATE STEAM HOSE,
CONDENSATE RETURN LINE, AND STEAM DISTRIBUTOR
PIPE.
1. Steam distributor pipe must be mounted on a plumb surface.
When on a plumb surface the standard distributor pipe is
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 provided by Carnes.
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.
Note: Over time and extended
heat, the situations described
in the previous paragraph can
occur. That's why it is import-
ant to perform monthly visual
inspections to maintain and
correct, when necessary,
improper routing of steam
and condensate lines.
1" Minimum Pipe Insulation
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 H.
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 over the outlet stub on the top of
the cylinder. Fasten 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 C.
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
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 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 temperature in duct is 55° to 60°F or less, recommended 10
feet of distance be used.
3. Under normal and average conditions, most absorption
distances will probably fall into the 4 to 5 feet length. This is
true, whether the unit is a 30 lb./hr. or less capacity or 30 lb./
hr. or more capacity.
4. If distance recommended can not be possible, then a drain
pan with drain capability may be required.
5. If the air in the duct can not hold the volume of steam, the only
recourse may be to lower the maximum output of the unit.
6. If shorter absorption distances are required, 3 ft. or less,
multiple distributor pipes could be used. 2 pipes split off one
steam hose or 2 pipes from a dual cylinder unit.
7. If even shorter absorption distances are required, 2 ft. or less,
then multi tube short absorption manifolds may be required.
You must keep in mind that there are a lot of variables involved
in proper steam distribution and absorption distances (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 humidi-
fiers, distance between humidifiers to distribution point and so
on). Since this is important to successful humidification, proper
planning must be a pre-requisite to good performance.
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