How Does a Furnace Vent Fuel? Three Sorts of Venting and How They Work.

🔥 How Does a Furnace Vent Fuel?

Propane and pure gasoline furnaces, whether or not they’re mid-efficiency or high-efficiency furnaces, will vent exhaust gases exterior by a vent pipe (additionally referred to as an exhaust flue) system.

There are three kinds of venting that we are going to talk about on this article; pure draft system, direct vent system, and energy vent system.

The primary distinction between the three vent varieties is the temperature of the flue gases.

If you happen to’re asking your self why the exhaust gases should be vented, it’s as a result of the method of burning fossil fuels can create poisonous gases like carbon monoxide.

🔥 How Older, Much less Environment friendly Furnaces Vent Fuel

Pure Draft Furnace Vent

CC Image by Bonnie Bogle through Flickr

You probably have a furnace that has a steel exhaust pipe, also called a B-vent pipe, which comes out the highest of it, then your furnace is taken into account a normal effectivity furnace and is roughly 70% environment friendly.

These furnaces have a much less environment friendly warmth exchanger and due to this fact have extraordinarily sizzling combustion gases that naturally draft out the flue pipe to the skin.

The exhaust pipe is normally routed by the chimney and out by the roof.

On the unfavourable facet, pure draft vents are extra conducive to backdrafts, which reduces effectivity and generally is a security concern.

What’s B-Vent Pipe?

furnace b vent pipe

B-vent makes use of a double wall of steel pipe.

The interior pipe makes use of reflecting aluminum which heats rapidly, with the aim of serving to the nice and cozy flue gases vent to the skin.

There may be airspace between the interior and outer steel pipes which supplies insulation in opposition to warmth loss to maintain the hotter flue gases naturally drafting.

The outer pipe is manufactured from corrosion-resistant galvanized metal.

This ensures energy and sturdiness.

Direct Vent

Old Furnace

In case your steel exhaust vent is routed out of the home, it’s seemingly a direct vent and makes use of an exhaust fan.

The sort of furnace has a barely extra environment friendly warmth exchanger that’s roughly 80% environment friendly; due to this fact, the combustion gases have a decrease temperature and need assistance getting vented to the skin.

The flue pipe on these furnaces is just sheet steel and may be extraordinarily sizzling to the contact.

Native codes are in place to make sure that the venting pipes don’t are available direct contact with flamable supplies.

What’s a Direct Vent Furnace?

A direct-vent furnace has a self-contained, sealed warmth exchanger that warms inside air by the house’s air throughout the sealed warmth exchanger.

The combustion byproducts are then vented exterior utilizing an induced exhaust motor, which signifies that they don’t should be connected to the chimney and may be put in on most exterior partitions.

🔥 How Excessive-Effectivity Furnaces Vent Flue Gases

Gas furnace combustion chamber in action

A high-efficiency furnace makes use of a main and secondary warmth exchanger to take away as a lot warmth vitality from the combustion course of as potential.

As a result of decrease temperature of the combustion gases, a steel exhaust pipe is now not wanted.

Subsequently your high-efficiency furnace makes use of both a single-pipe or two-pipe vent system.

These propane or pure gasoline furnaces are thought-about to be at the least 90% environment friendly.

One of many challenges with high-efficiency condensing furnaces is that the combustion gases find yourself condensing on the within partitions of the PVC pipe, drain again to the furnace, after which out the condensate drain line.

The combustion by-products have a excessive PH degree and are thought-about acidic, so please be certain to empty them accordingly.

Single-Pipe vs. Two-Pipe

two pipe vented gas furnace

All propane and pure gasoline furnaces require adequate carbon dioxide for the furnace to succeed in full combustion.

If there isn’t sufficient, then combustion byproducts may embody carbon monoxide, which could possibly be toxic to your loved ones.

A single-pipe heating system makes use of combustion air from the house across the furnace.

The issue with that is that the furnace may expend the entire air within the room.

So, it is for that reason that native codes are in place to make sure adequate air is out there for single-pipe heating methods.

NOTE: All propane and pure gasoline furnaces have the aptitude to be put in with two-pipe furnace venting.

Many contractors will solely set up a single venting pipe system when a two-pipe system ensures that your gasoline furnace all the time has sufficient combustion air.

Ask your HVAC contractor what they do earlier than accepting their bid.

For the most secure HVAC system potential, request that your furnace’s exhaust have two pipes.

PRO TIP: Most areas require particular high-temperature PVC pipes to be used on high-efficiency furnace installations.

🔥 Blocked Or Broken Exhaust Pipe

Furnace horizontal vent termination kit
Furnace horizontal vent termination package fitted exterior of a residential dwelling

If the flue pipes are blocked or broken in any means, the combustion course of could create carbon monoxide.

Different points can embody flue venting cracking or joints failing.

What could cause a vent pipe to get blocked?

Bugs, small animals, bushes, snow, or ice can simply block the furnace venting, which may trigger any of the above points to happen.

Most furnaces nowadays have security switches in place to show the furnace off earlier than any injury may come up.

🛑 What’s The Hazard?

A blocked vent pipe may solely make a furnace quick cycle and nothing extra.

Nevertheless, a blocked or cracked flue pipe additionally has the potential to flow into carbon monoxide into your own home.


🔥 Ultimate Ideas on Furnace Venting Techniques

Clearly, making a choice on what kind of furnace to purchase has extra variables than simply the venting system, nevertheless it’s undoubtedly one to think about.

Usually, I might say {that a} direct vent is the least costly possibility.

It’s simpler to put in than a pure draft however isn’t as environment friendly as a system with one or two PVC flue pipes.

Phyxter Approved Logo on Service Truck

If you happen to discovered this text on furnace vent varieties useful however you’re nonetheless in search of extra data, I might advocate contacting a extremely rated and skilled native HVAC firm to ask for assist.

Guarantee they totally clarify their suggestions for furnace sizing and vent varieties.

Wish to be taught extra about your own home’s heating system? Be happy to take a look at our different furnace articles!