Lochinvar SNA285-125 Manuale Utente

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4  
Vertical direct venting 
Vent/air termination – vertical
Follow instructions below when determining 
vent location to avoid possibility of severe 
personal injury, death or substantial 
property damage.
 
Figure 4-1A Vertical Termination of Air and Vent
8.  Locate terminations so they are not likely to be damaged by 
foreign objects, such as stones or balls, or subject to buildup 
of leaves or sediment.
 WARNING
 WARNING
       
Installation & Service Manual
TM
Rooftop vent and air inlet terminations 
must terminate in the same pressure zone, 
unless vertical vent sidewall air is set up as 
shown in the General Venting - Vertical 
Vent, Sidewall Air Section.
6" (152 MM) MINIMUM
ABOVE ROOF / 
SNOW LINE
VENT
COM,BUSTION
       AIR
ALTERNATE INTAKE LOCATIONS:
INTAKE PIPES MAY BE LOCATED
ANYWHERE WITHIN 24” (610 MM) 
OF VENT PIPE
VENT OUTLET
36” (914 MM) MINIMUM
ABOVE AIR INLET
BIRD SCREEN
(TYPICAL)
Figure 4-1B Stainless Steel  Vertical Termination of Air 
and Vent
Determine location
Locate the vent/air terminations using the following 
guidelines:
1.  The total length of piping for vent or air must not exceed 
the limits given in the General Venting Section on page  
17 of this manual.
2.  Prepare the vent termination and the air termination 
elbow (FIG. 4-1A) by inserting bird screens. Bird screens 
should be obtained locally.
3.  The vent must terminate at least 3 feet above the highest 
place in which the vent penetrates the roof and at least     
2 feet above any part of a building within 10 horizontal 
feet.
4.  The air piping must terminate in a down-turned 180° 
return pipe no further than 2 feet from the center of the 
vent pipe.  This placement avoids recirculation of flue 
products into the combustion air stream.
5.  The vent piping must terminate in an up-turned coupling 
as shown in FIG. 4-1A.  The top of the coupling must 
be at least 1 foot above the air intake.  When the vent 
termination uses a rain cap as illustrated in FIG. 4-1B 
maintain at least 36" (914 mm) above the air inlet.  The 
air inlet pipe and vent pipe can be located in any desired 
position on the roof, but must always be no further than 
2 feet (.6 m) apart and with the vent termination at least 
1 foot for PVC and 3 feet for stainless steel, above the air 
intake.
6.  Maintain the required dimensions of the finished 
termination piping as shown in FIG. 4-1A.
7.  Do not extend exposed vent pipe outside of building 
more than shown in this document.  Condensate could 
freeze and block vent pipe.