54
APPENDIX
Inside Combustion Air
Contamination:
All boilers experience some condensation during start-
up. The condensate from flue gas is slightly acidic. In
most cases the pH level is not harmful to vents or
drains. When combustion air is contaminated by
vapors from products in areas listed below, the acidic
levels in the condensate increase. Higher acidic levels
attack many materials, including stainless steel com-
monly used in high efficiency systems.
The ADB can use special corrosion-resistant non-
metallic vent material. You may, however, choose to
use outside combustion air for one or more of these
reasons:
•
installation is in an area containing contaminants
listed below which will induce acidic condensation.
• you want to reduce infiltration into your building
through openings around windows and doors.
•
you are using AL29-4C stainless steel vent pipe,
which is more corrosion-resistant than standard
metallic vent pipe. In extremely contaminated
area, this may also experience deterioration.
Products causing contaminated combustion air:
•
spray cans containing chloro/fluorocarbons
•
permanent wave solutions
• chlorinated
waxes/cleaners
•
chlorine-based swimming pool chemicals
•
calcium chloride used for thawing
•
sodium chloride used for water softening
• refrigerant
leaks
•
paint or varnish removers
•
hydrochloric acid/muriatic acid
•
cements and glues
•
anti-static fabric softeners used in clothes dryers
•
chloride-type bleaches, detergents, and cleaning
solvents found in household laundry rooms
•
adhesives used to fasten building products
•
... and other similar products
Areas causing contaminated combustion air:
•
dry cleaning/laundry areas and establishments
•
metal fabrication plants
• beauty
shops
•
refrigeration repair shops
•
photo processing plants
•
auto body shops
•
plastic manufacturing plants
•
furniture refinishing areas and establishments
•
new building construction
• remodeling
areas
Check for areas and products as listed above before
installing boiler. If found:
•
remove products permanently, OR
•
provide outdoor combustion air
Summary of Contents for 751
Page 2: ...2...
Page 6: ...6 Component Locations Fig 1 Component Locations...
Page 15: ...15 Fig 6 Dual Boiler Piping Fig 7 Dual Boiler Piping with CHX...
Page 20: ...20 Fig 13 Single Boiler Pool Application Fig 14 Single Boiler Pool Application with CHX...
