How Do I Tell What Type of Round Flue I Have: Solid-Pack Insulated, Double-Walled Air Insulated, Triple-Wall Insulated, Clay Masonry Flues, Single Pipe Metal Flues or Flexible Liner Flue?
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Selecting the Right Round Chimney Cap for Round Flues
Your round chimney flue will need the correct type of round chimney cap, one that corresponds
to the way it is constructed. There are 6 types of round flues; the type of round flue you have determines which chimney caps for round flues will work for you.
With any existing chimney cap removed, look down your flue and match it with one of the
drawings below. The discussion next to the drawing will tell you what kind of flue you have and what types of round chimney caps are appropriate.
The drawing at the left shows a double wall air cooled flue.
The flue has an air jacket outside of it. The flue is cooled by air circulating between the two walls. For this reason, you'll need a round chimney cap made
expressly for a double wall air cooled flue. The chimney caps below are all designed to let cooling air circulate properly in the air jacket. Choices include:
The Weathershield for double and triple wall air cooled flues (unless you have smoke coming out of your fireplace.)
The Vacu-Stack for air cooled chimneys if your fireplace smokes on windy days, but not on calm days.
The ENERVEX (formerly Exhausto) chimney fan with an air cooled adaptor. The Enervex fan solves smoky fireplace problems of all kinds, even if your chimney is incorrectly designed and constructed. Call 888 834 7375 for help in selecting the correct size Enervex fan and adaptor.
Triple wall air cooled flues, sometimes called triple wall air
insulated flues, have two air jackets surrounding a central flue pipe. Air circulating inside the air jackets cools the flue. You can use exactly the same chimney caps described
above for double wall air cooled flues, because all three are designed for use with double wall or triple wall air cooled round flues.
The WeatherShield chimney cap for double and triple wall air cooled flues if your fireplace is not smoking.
The Vacu-Stack round chimney cap for air cooled flues if your fireplace smokes on windy days only.
The ENERVEX chimney fan, with an air cooled adaptor, will solve any kind of smoky fireplace problem. It can even compensate for a badly designed chimney. Please call us at 888 834 7375 so we can help you choose the correct Enervex fan and adaptor.
Solid pack flues
have insulation sandwiched between two layers of metal. These are sometimes called double wall insulated flues or solid packed insulated flues. In most, the insulation is sealed in by metal ring at each end of a section of flue pipe. When you look down the flue, you will see these seals, not the insulation material itself.
Chimney caps for round flues that have covered insulation include:
HomeSaver Pro Guardian chimney caps and WeatherShield chimney caps for solid pack flues, if your fireplace has a good draft and is not smoking.
Vacu-Stack chimney caps for solid pack flues if your fireplace smokes on windy days only. As wind passes through a VacuStack chimney cap it creates a vacuum over the flue, pulling the smoke up the chimney.
ENERVEX Fans (formerly called Exhausto fans) will correct
fireplaces that give off smoke for any reason, even fireplaces with incorrectly constructed flues. You will need a solid pack adaptor with your Enervex fan. Help for
selecting the right size Enervex fan and adaptor is as nearby as your phone: just call 888 834 7375.
When you look down your flue pipe you may see exposed insulation material
between an inner metal pipe and an outer one. If so, you have a solid pack flue with exposed insulation. These flues need the same chimney caps used with air cooled
flues, so that the insulation material is protected from the elements:
WeatherShield chimney caps for air cooled flues if your chimney is drawing satisfactorily.
Vacu-Stack chimney caps for air cooled flues for back-puffing that happens only on windy days.
ENERVEX (Exhausto) fans with adaptors for air cooled flues. Please call 888 834 7375 for help in choosing the correct size Enervex fan and adaptor.
At the left you will see a clay flue, which is also called a masonry flue. These
are pipes made of terra cotta—like a flower pot.
Appropriate chimney caps for round flues made of clay masonry
include:
ENERVEX Fans with solid pack adaptors for smoky fireplaces or wood stoves.
When chimneys are re-lined, chimney professionals use a flexible metal
flue liner, like the one shown at the left. Round chimney caps used with flexible metal liner include:
ENERVEX Fans with solid pack adaptors if you have a smoky fireplace problem, regardless of the cause or severity.
If you still need a little help with identifying your flue type or choosing chimney caps for
round flues, our friendly Chimney Cap Experts are standing by at 888-834-7375. Or, you can
e-mail us at with your questions.
Please download the Easy Measure Guide by FireplaceMall.com to make sure
you measure correctly for your chimney cap. It also show the six types of round flues. You can even take it onto the roof with you!
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