Burnham Series 8H/8HE Boiler Manual De Propietario

2.1    Vents, or breeching ducts, are generally less flexible 

in design location than are water pipes, gas pipes 

or electrical lines.  To avoid conflicts for a given 

location, design and layout the vents in this section 

before proceeding to other sections of this manual.

2.2    Obtain a scaled drawing of the boiler room.  Note the 

floor size, ceiling height, exterior walls, and chimney 

location, if provided.

2.3    Determine the input required to the system.  It is 

recommended that the heating load be determined by 

an accurate calculation of the heat loss of the structure 

using methods contained in the ASHRAE Guide.  If 

service water is to be added capacity as described in 

paragraph 3.13 of this manual.  The boiler capacity 

so obtained is net rating to input.  Record the input 

required on the boiler room drawing.

2.4    Using Figure 2-2 for the input found in 2.3 above, find 

the number of modules recommended.  Those module 

combinations shown represent the best selection for 

lowest first cost.  Other combinations may be selected, 

within the following guidelines:

1)   Modules using a sequencing control system, such 

as Tekmar described in Section 5.0, should not 

vary by more than one size.

2)   Modules using a combined vent system should not 

vary by more than one size.

3)   The combined vent sizing procedures in this 

section are based on a maximum of eight modules 

using a common vent system.  If it is desired to 

serve more than eight modules with a common 

vent system, the specific requirements should 

be referred to the BURNHAM COMMERCIAL 

Application Engineering Department.

Refer to Figure 2-3 for individual module inputs.

2.4.1  Sketch on the boiler room drawing the approximate 

location of the modules.  Figures 2-4 thru 2-9 show 

several layouts that can be used depending on the size 

and shape of the boiler room and chimney location, 

if provided.  Refer to Figure 2-3 for dimensional data 

on individual modules.  Select the layout which best 

fits the boiler room.  Bear in mind that for combined 

vent systems it is desirable to keep horizontal laterals 

as short as possible.  On a combined vent system for 

which a fixed chimney is provided, it is desirable to 

place the first module close to the chimney.

2.4.2  If the factory fabricated water manifolds are to be 

used, 805H, 806H, and 807HE modules should be laid 

out with 28½” module spacing and 808HE, 809HE, 

and 810HE modules should be laid out with 40” 

module spacing.  If an 807HE and an 808HE module 

are to be connected to a common manifold, use the 

longer manifold with 40” spacing.  Otherwise, any 

module spacing that allows at least 1 inch jacket –to-

jacket spacing if acceptable, pending local or state 

code requirements that may require greater module to 

module spacing.

2.4.3 Refer to Figure 2-10 for minimum clearances around 

modules to combustible materials and for service 

access.  CAUTION:  Local fire ordinances may be 

more restrictive and should be complied with.

2.5    One of the serious errors made in layout of a boiler 

room is the failure to provide sufficient ventilation 

air.  Insufficient ventilation air will cause incomplete 

combustion, poor ignition, accumulation of soot in 

the boiler, or the production of toxic gases.  Many 

service calls for dirty boilers, nuisance lock outs, 

noisy ignition, or obnoxious odors are traceable to 

insufficient ventilation air.  Use Figure 2-11 at the 

input desired to find the recommended free area of the 

ventilation opening required.  Reference to Figures 

1-2 thru 1-4 should be made in order to understand 

the types of installations described in the headings 

of Figure 2-11.  Record the free ventilation area 

required on the plans of the boiler room and sketch 

the openings like those shown in figures 1-2 thru 1-4 

respectively.

2.6    Individual vents as shown in Figure 1-7 are highly 

recommended if the job site conditions allow.  

Individual vents are particularly useful in boiler rooms 

having a low ceiling height.  Individual vents are 

easy to design and in many cases result in the lowest 

installed cost.  They also are the most dependable in 

operation and less susceptible to condensation than are 

combined vents.  To size individual vents, use Figure 

2-12 with the vent height available, the lateral length, 

size of module and type of vent pipe.

2.7    Combined vents will perform satisfactorily if strict 

design procedures are followed.  Referring to Figures 

2-4 thru 2-9, note that a connector rise F of at least 

one foot is required.  A connector rise F of three feet 

is desirable.  Thus, to make the desired connector rise 

and have space for the manifold vent, the minimum 

boiler room ceiling height must be equal to:

 

  32½”  Module Height

 

  +   ) 

Drafthood Height

 

  +  F 

Minimum Connector Rise

 

  +  CV  Manifold Diameter

  

+  6” 

Clearance

 

  =  

Minimum Ceiling Height

 

  If the minimum ceiling height above is not available, 

common vents will not perform satisfactorily and 

should not be used.