Patterson-Kelley MACH-05 Manual Do Utilizador

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  MACH®  Series
 
Gas-Fired Boiler 
Installation 
 
 
Page  7 
An external electrical disconnect (not supplied with 
the boiler) with adequate overload protection is 
required.  The boiler must be grounded in accordance 
with local codes or in the absence of such 
requirements, in the U.S. with National Electrical 
Codes, ANSI/NFPA No. 70 latest edition and in 
Canada to the current Canadian Electrical Code, Part I, 
CSA C22.1. 
 
Note:  A dedicated earth ground (green wire) is 
required to avoid nuisance shutdowns.  Do not ground 
through the conduit.  It is also important that proper 
polarity be maintained. 
 
Note:  Refer to Terminal Block Assignments (Section 
6.1.1).   
 
 
 
 
 
Electrical Connections at Rear of Boiler 
 
 
3.5
  
C
OMBUSTION 
A
IR
 
Combustion air must be free from dust, lint, etc.  The 
presence of such materials in the air supplied to the 
burner could cause nuisance "Low Air" shutdowns or 
premature burner failure.  The boiler should not be 
operated during construction while the possibility of 
drywall dust, demolition dust, etc. exists.  
The combustion air supply must be completely free of 
chemical fumes which may be corrosive when burned 
in the boiler.  Common chemicals which must be 
avoided are fluorocarbons and other halogenated 
compounds, most commonly present as refrigerants or 
solvents, such as freon, trichlorethylene, 
perchlorethylene, chlorine, etc.  These chemicals, 
when burned, form acids which quickly attack the 
boiler and the boiler stack.  The result is improper 
combustion and premature boiler failure. 
Provisions for combustion and ventilation air must be 
in accordance with Section 5.3, Air for Combustion 
and Ventilation, of the National Fuel Gas Code, 
ANSI Z223.1, latest edition, or applicable provisions 
of the local building codes.  In Canada, combustion 
air openings shall comply with CSA B.149 
Installation Code.  The formula is 1 sq. in. per 1,000 
Btu/hr of gas input not less than 100 sq. in.  The 
location shall be neither more than 18", nor less than 
6" above the floor level.  
The boiler room shall be provided with two openings 
to ensure adequate combustion air and proper 
ventilation.  One opening should be 6 to 12 inches 
above the floor and the other 6 to 12 inches below the 
ceiling, preferably on opposite walls.  The size of 
each opening is determined by whether air is taken 
from inside or outside the building.  In Canada, 
ventilation air openings shall be at least 10% of the 
cross sectional area required for combustion air, but 
not less than 10 square inches.  It is to be located at 
the highest practical point communicating with 
outdoors.  
 
WARNING!  
Under no circumstances shall the boiler room 
ever be under a negative pressure.  Particular 
care should be taken when exhaust fans, 
compressors, air-handling units or other 
equipment may rob air from the boiler. 
 
3.5.1  Air Inlet Requirements   
If air is taken directly from outside the building, each 
opening (minimum of two) should have a net free 
area of 1 square inch for each 4,000 Btu per hour of 
total boiler input.  For instance, 112.5 square inches 
are required for 450,000 Btu per hour input. 
When air is taken from the outdoors through a 
vertical duct, 1 square inch per 4,000 Btu per hour is 
required.  If a horizontal duct is used, 1 square inch 
per 2,000 Btu per hour is required, i.e., 225 square 
inches for 450,000 Btu per hour input. 
Low Voltage 
Control Junction 
Box 
120 Volt 
Electrical Control 
Junction Box