Armstrong World Industries EHU-704 User Manual

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c.   Use the template provided to cut installation    
holes in the duct for the dispersion tube 
as in Figure 7-2 (and optional drain tube,
Figure 7-3).
d.   Insert the dispersion tube into the duct so 
the holes face upward. Fasten the mounting 
plate to the outside of the duct with sheet 
metal screws. If the dispersion tube is 36"  
long or more, support the far end with
threaded rod or similar means.
e.   Connect the dispersion tube to the steam generator using 1¼" (EHU-701) or 1½" (EHU-703,704)
nom. size hard copper tube (customer supplied) and the two short hoses supplied with the 
humidifier (Figure 8-1). Pipe size may     
need to be increased to 1½" or 2" 
when piping runs are long or back 
pressure in duct is high, see Figure 9-2. 
If piping plus duct back pressure 
exceeds 4" WC, please consult factory.
In addition, a short length of nominal 
1½" threaded black iron pipe 
and a copper tube to female pipe
thread adaptor must be supplied
by the customer for attaching the
piping to 703 or 704 tanks (Figure 8-2).
A 1½" to 1¼" reducer will be required 
to connect the dispersion tube to the steam pipe of Models EHU-703/704 (Figure 8-5).
The steam pipe must be free of kinks and sags to allow for gravity drainage of condensate. 
(Provide pitch of 1" per foot towards the unit.) Pipe supports may be required to accomplish
this. Insulate the copper tube to minimize condensation.
The preferred installation of the 
dispersion tube is above the 
humidifier with a maximum piping 
run of 20 feet or less (Figure 8-3).
Figure 8-4 shows the correct 
installation when:
1)  You cannot achieve a 1" per 
foot reverse slope of the piping.
2)  Piping runs range from 20 to the                    
maximum of 40 feet of equivalent run. 
3)  Elbows or vertical risers must be 
placed in the piping.       
4)  The steam dispersion tube MUST BE
below the humidifier. For this installation 
use a 1¼" copper tee for the drain 
connection of an EHU-701 or a 1½" 
copper tee for EHU-703 or 704 
(Figure 8-5).
8
1-1/2" Copper Tube
Copper Tube
Female Pipe Adapter
1-1/2" Pipe
Hose Clamp
2" I.D. Hose
Steam
Outlet
EHU-701
Floor
Drain
6" Water Seal
Duct Above Outlet
Holes in dispersion 
tube to be installed 
in "UP" position
1-1/2" to 1-1/4" Copper 
Reducer if Needed
1-1/2" I.D. Hose
1/2" PVC
Tubing
1/2" O.D.
Copper Tubing
1-1/4" Copper Tube
1-1/2" I.D. Hose
EHU-701 
Steam Generator Top
Figure 8-1. EHU 701
Figure 8-2. EHU 703/704
Figure 8-3
Figure 8-4
Figure 8-5