Does a high efficiency furnace need outside air?
A high-efficiency furnace is more complex than a conventional furnace since there are more potential problems.The second heat exchanger in a high-efficiency furnace extracts more heat from the air than the first one.A tube is usually placed in a floor drain to drain the water out of the air.The presence of this drainage tube can be used to identify a high-efficiency furnace.
The main difference between a conventional furnace and a condensing furnace is the heat exchanger technology used to extract heat from the combustion process and exhaust the gases.If you notice, the exhaust gases exit your home through a small pipe, rather than the large metal flue found in a conventional furnace.You can see the air intake vent and the exhaust vent on the roof of your home.This means a direct-vent system.
A single-pipe vent system is used in some high-efficiency furnaces, where the air is drawn from the indoor air supply, and a single pipe serves to vent the exhaust gases.There are some furnaces that can be adapted for direct-vent installation.
There are five different conditions that you can check for when a condensing furnace has a weak flame or will not ignite at all.
An obstruction of the air intake vent pipe in a direct-vent two-pipe system will cause serious problems.
If the furnace combustion problem is caused by an obstruction of the air supply pipe, you should remove the burner compartment cover.Free air will be provided to the chamber.The dedicated combustion air supply vent pipe may be obstruction if you remove the cover.
Birds' nest or leaves in the air intake vent are obstructions that need to be checked out.If the vent needs to be cleaned, use a plumbing tool known as a sink auger.There is a metal screen over the end of the vent.
Short-circuiting can occur when a direct-vent system has its air intake and exhaust vents installed on the outside of the home.
The exhaust vent gases can be drawn back into the air intake vent when it's too close together.The air reaching the furnace does not have enough oxygen.
Installation of separate vent pipes using a two-pipe system can be used to avoid this problem.A qualified heating, ventilating, and air conditioning contractor is likely to fix this problem.
In addition to the ignition failures common with a conventional furnace, such as a faulty igniter, ignition problems on a condensing furnace may be related to a clogged flue vent condensate line.A partially clogged condensate line can cause the furnace's pressure switch to trip.
The pressure switch may open if the drain is blocked by debris or frozen condensate.The pressure switch will not operate the furnace until the drain is clear of the condensate.If you notice water coming out of the secondary heat exchanger when the drain line is disconnected, that's a sign of a blocked drain.
There may be intermittent problems caused by a drain.The furnace can start and stop if the water flow is restricted, but it can't start again until the problem is fixed.