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Draft hood not connected properly to the flue on an atmospheric boiler
Flue Size Chimney Liners Corrosion - It is important that furnace flues are sized properly or vent into chimneys that have chimney liners in them. Many older heating systems were oversized. From the furnace to the chimney used to vent the exhaust gases many older systems are oversized.
These older systems were also inefficient. Modern furnaces and boilers are far more efficient than the older inefficient systems. The older systems had flue gases that contained more heat than the newer modern heating systems. It is, therefore, important that flue size is sized properly for the newer furnaces because the flue gases are highly corrosive when they condense.
Flue Size Chimney Liners Corrosion
Condensation occurs in the flue gases when they cool too fast. This can happen on very cold nights or with chimneys or flues that are oversized. Corrosion inside a chimney causes the masonry to crumble and crack. Even terracotta-lined chimneys are not immune to this problem as the terra cotta has masonry joints that can be corroded by the condensed gases.
As the proper flue vent material is used so is the proper size important. This issue is covered in the mechanical code and the fuel gas code. It is important to make sure the existing system can handle the flue gases from your boiler or furnace. If the existing system cannot handle the flue gases you will suffer in the future. A failure in either the chimney or the flue vent will eventually occur.
Flue Size Chimney Liners Corrosion - Conclusion
If you install a new boiler or furnace that has a higher AFUE of 80% or more and these furnaces or boilers use the chimney for primary venting a liner should be installed. If you install a high-efficiency furnace or boiler that uses PVC for venting combustion gases and the old furnace or boiler shared the chimney with a gas-fired water heater a liner needs to be installed in the chimney for the gas-fired water heater.
Gas or oil-fired water heaters, furnaces, or boilers all need a properly sized flue and chimney liner in order to prevent future problems with corrosion including problems with chimney collapsed. Make sure your flue is safe and sized properly by an HVAC professional today.
Flue Size Chimney Liners Corrosion
