Roberts Gorden CTHN-125 Manual De Usuario

31

The radiant tube length fixed for each burner is 
shown on Page 30, Table 10.

Any tube beyond the radiant tube length is 
considered manifold. Manifold tube can be used to 
lengthen tube runs beyond the radiant tube length; to 
connect multiple runs of tubing and connect the 
system to the pump. Minimum and maximum 
manifold tube lengths are shown 

Table 10. The table must be used in conjunction 
with the additional rules for the diameter and 
length of manifold in a system, as described 

Page 31, Section 9.5.1 through Page 35, Section 
9.6.3.

1. Manifold diameter for systems containing less 

than 320,000 Btu/h input can be 4" (10 cm) or 
6" (15 cm).

2. Manifold diameter for systems containing 

320,000 Btu/h input and greater must be 6"
(15 cm).
Exception:

 If total manifold tube length is 70' 

(21 m) or less, 4" (10 cm) diameter manifold 
tube can be used for systems up to 
800,000 Btu/h.

Most CTHN multiburner layouts can be classified as 
one of the following five layout types:

Flag, Modified In-Series, T, Fork or Herringbone.  
Please refer to Page 31, Section 9.6.1 through Page 
35, Section 9.6.3 for explanation of manifold rules 
and basic diagrams of each layout type. The 
diagrams show very simple examples of each layout 
type. Actual layouts will vary in total number of 
burners in the system as well as the overall shape of 
the system. Additional pieces such as elbows may 
change the overall layout appearance but are usually 
considered a variant of one of the five multiburner 
layout types.

See Page 32, Figure 19 through Page 32, Figure 20 
for diagrams of Flag and Modified In-Series layouts. 
Minimum and maximum manifold tube length applies 
to all tubing between the end of a radiant tube run 
and a tee or cross; all tubing between any tees and/
or crosses; and all tubing between the last tee or 
cross and the pump. See Page 30, Table 10.

Example: Consider a Flag or Modified In-Series 
layout with five CTHN-100 burners. Page 30, Table 10 
shows a minimum of 6' (2 m) and a maximum of 45' 
(13.5 m) of manifold tube required per burner.  
Therefore the entire five-burner system must have 
between 30' (10 m) and 225' (69 m) of manifold 
tubing. The manifold tubing is in addition to the 40' 
(12 m) of radiant tube per burner. Radiant tube may 
end at a tee, or runs may be lengthened by adding 
some manifold tube between the end of the radiant 
tube and a tee. Each burner in the system (except for 
the burner furthest from the pump) must use a 
damper coupling to properly adjust the vacuum at 
each burner. The damper coupling may be placed 
anywhere between the end of the radiant pipe and 
the tee.