Справочник Пользователя для Burnham FREEDOM 101008-01R1-2/07

There are three basic ways to vent this boiler:

•  Horizontal (“Side Wall”) Concentric Venting - Vent system exits the building through an outside wall. Concentric 

venting consists of a “pipe within a pipe”. Flue gas exits the building through the inner pipe and combustion air is 
drawn into the boiler through the space between the inner and outer pipe.

•  Horizontal (“Side Wall”) Twin Pipe Venting - Vent system exits the building through an outside wall. Combustion air 

and fl ue gas are routed between the boiler and outdoors using separate pipes.   

•  Vertical Twin Pipe Venting - Vent system exits the building through a roof. Combustion air and fl ue gas are routed 

between the boiler and outdoors using separate pipes. 

 

All of these systems are considered “direct vent” because in all of them, air for combustion is drawn directly from the 
outdoors into the boiler. A description of all of these venting options are shown in Tables 7.1 and 7.8. For clarity, these 
vent options are numbered from 1 to 6. One of the vent option columns in Tables 7.1 or 7.8 must match the planned vent 
and air intake system exactly. In addition, observe the following guidelines:

1)   Approved vent systems - Use only one of the approved vent systems shown in Tables 7.4 or 7.5. These vent systems fall 

into two basic categories:

•  Concentric Vent System - The standard boiler is supplied with a concentric vent system having a maximum usable 

length of 25” (Figure 1.1). For longer runs, additional straight lengths and elbows are available from U.S. Boiler. Each 
U.S. Boiler concentric vent component consists of an inner pipe of polypropylene and the outer pipe of steel. Integral 
gaskets on each concentric fi tting provide a gas tight seal.  A list of all U.S. Boiler concentric vent components is 
shown in Table 7.4. 

      In this manual, concentric pipe sizes are called out in terms of the inner and outer pipe nominal diameters in 

millimeters. For example, “60/100mm” pipe consists of a 60mm exhaust pipe inside a 100mm diameter outer pipe.   

•  Twin Pipe Vent Systems - Approved vent systems are made of a special stainless steel alloy (AL29-4C) for protection 

against corrosive fl ue gas condensate. They are designed to provide a gas tight seal at all joints and seams so that fl ue 
gas does not enter the building. Each approved vent system has a unique method for installation - do not attempt to 
mix components from different vent systems. A list of approved twin pipe vent systems is shown in Table 7.5.  Note 
that a special vent collar (U.S. Boiler P/N 101004-01) is required if the boiler is to be vented with one of the approved 
stainless vent systems.   

2)  Maximum Vent and Air Intake Lengths - The maximum length of the vent air intake piping depends upon the vent option 

selected and the boiler size. See Table 7.1 or 7.8  for the maximum vent length. In horizontal vent systems, the lengths