Operating instructions

75D0004 13
MLDV Series Gas Fireplace


There are two basic types of direct-vent installation:
• Horizontal Termination
• Vertical Termination
It is important to select the proper length of vent pipe for
the type of termination you choose. It is also important to
note the wall thickness.

Select the amount of vertical rise desired. All horizontal run
of venting must have 1/4" rise for every 1" of run towards
the termination below 7
1
/ feet of vertical rise. With 7
1
/ feet
or more vertical rise off top of replace, the horizontal run
may run level. NEVER run vent piping downward.
You may use up to three 90° elbows in this vent congu-
ration. Refer to Horizontal Termination Congurations on
Pages 17 and 18.

Measure the distance from the replace oor to the ceil-
ing. Add the ceiling thickness, the vertical rise in an attic
or second story, and allow for sufcient vent height above
the roof line.
 You may use two 45° elbows in place of a 90° elbow.
You must follow rise to run ratios when using 45° elbows.
The appliance is approved for use with three 90° elbows
maximum or a combination of 90° and 45° elbows up to a
maximum of 70°.

      

      

    



   
    
    
          

     


       
      
   
     

Z\x

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   




   
     
     
      

 
    
   


    


For two-story applications, restops are required at each
oor level. If an offset is needed in the attic, additional pipe
and elbows will be required.
You may use a chase with a vent termination with exposed
pipe on the exterior of the house. Refer to Installing Vent
System in a Chase below. If pipe is enclosed in chase, it
is not exposed.
It is very important that the venting system maintain its bal-
ance between the combustion air intake and the ue gas
exhaust. Certain limitations apply to vent congurations
and must be strictly followed.


A chase is a vertical boxlike structure built to enclose
venting that runs along the outside of a building. A chase
is required for such venting.