Assure this inexpensive 3-4 inch Increaser is NOT used in your professional Insert install!

[Don2222]

Hello

I have seen this in too many fireplace installs lately and all were done by experienced professionals. 4" flue liner is highly recommended and is used most of the time now in fireplace installations, however this single wall 3-4" increaser saves the installer alot of time and money but can cause problems. Stoves like a Quad CB1200 and a Breckwell 2000i do not have room for 4" diameter pipe up the back. Therefore the right pipe and adapters should be used to prevent smoke leaking into the house!

The proper set of pipes, stove adapter and flex adapter should be used to prevent smoke leakage
See pics, click to enlarge.

Here is a good example:

Pic 1-5 Quadrafire CB1200i
Pic 1 - Increaser with 4" liner hitting the back of the stove and being pushed apart
Pic 2 - Increaser by itself
Pic 3 - Inside increaser shows how the smoke in the stove can escape between the crimped edge of the flex liner and the increaser. This is not a safe design. RTV can seal it but the pressure will make it fail eventually! See red arrows.
Pic 4 - The proper set of pipes and increaser with flex adapter. The flex adapter does not let smoke up the side.
Pic 5 - Duravent Flex Adapter

Pic 6 - Breckwell P2000i correct pipes and adapters

 

[Lake Girl]

No fireplace here but good to know Don ... pics makes it easier to understand the problem so thanks for taking the time.

 

[Don2222]

No fireplace here but good to know Don ... pics makes it easier to understand the problem so thanks for taking the time.

Thanks Lake Girl
This problem could not be seen until the pipes were all apart. When the exhaust blower failed the room filled up with smoke. A new exhaust blower made the stove work ok but that bad increaser was a real danger!
I also added an OAK so smoke would not back out of the air inlet pipe in case of a bad down draft or power outage.
Then I put fire proof Roxul insulation on the damper shelf around both vent pipes to keep the warm air in the room. Now the stove is safe and warm as possible!

 

[ZBrooks]

They're going to think that they have a new stove. Well done.

 

[smwilliamson]

little 3" double wall does the trick though I do not ever recommend using 3" liner for any installation ever. Most stove owners at pull out a heavy insert so 4"!gives some the flexibility of less cleaning