Condensing gas furnaces achieve their high levels of efficiency by adding another step to the fuel burning and venting process.
High efficiency furnace exhaust.
They include a second heat exchanger that reclaims additional heat from the system s exhaust gases before they are vented away.
High efficiency condensing furnaces have two stage combustion to extract as much heat energy as possible from burning gas.
In a conventional furnace the hot exhaust discharge has more time to exit a chimney flue and move away from a home or business before it condenses.
Venting for high efficiency gas furnaces materials due to the condensing nature of a high efficiency furnace its venting must be made of a material that is resistant to corrosion.
After the first stage the hot exhaust gasses are cycled through a second combustion stage resulting in exhaust with very little heat.
This high efficiency venting system must be installed when you install the new furnace.
A high efficiency furnace uses a different type of venting system because it extracts the heat that remains in those combustion gases before venting the resultant mixture of water and carbon dioxide.
Other aspects of high efficiency furnace venting.
The pvc pipes are used for air intake exhaust gas and to remove the corrosive condensation resulting from the combustion process.
In a great majority of cases plastic piping is used to vent high efficiency equipment.
It is classified as type bh venting.
This process creates condensate or moisture from the furnace s heat exchanger.
These pvc pipes are connected to the furnace and expelled outside.
High efficiency or condensing furnaces exhaust the combustion gases and bring in fresh air through pvc pipes to the outside usually routed through the sidewall of the house.
If not installed correctly or checked regularly problems in these pipes can affect the operation of the furnace itself.