Application
For use with high efficiency category II, III and IV natural gas-burning or propane fired appliances such as gas boilers, furnaces, unit and radiant tube heaters, tankless water heaters, pool heaters and direct vent appliances.
Appliance Vent Categories | ||
Negative pressure venting | Positive pressure venting | |
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Category I Combustion Efficiency 83% or less Use standard venting Masonry or Type B Vent |
Category III
|
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Category II Combustion Efficiency Over 83% Use only special gas vent as specified by manufacturer |
Category IV
|
Listings/Standards
NFPA 54
UL 1738
ULC-S636
Construction
Flue Material Thickness:
3" - 5"/.015, AL29-4C (Standard) or 444 stainless steel (Optional)
Casing Material Thickness:
3" - 5"/.018, aluminized (Standard), 430, 304, or 316 stainless steel (Optional)
Diameters
3" - 5"
Clearances
See Product Catalog: Design Manual – Corr/Guard® 3"-5"_L2158.pdf
Appliance Vent Categories | ||
Negative pressure venting | Positive pressure venting | |
![]() |
Category I Combustion Efficiency 83% or less Use standard venting Masonry or Type B Vent |
Category III
|
![]() |
Category II Combustion Efficiency Over 83% Use only special condensing service vent as specified by manufacturer |
Category IV
|
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