More on Vermont Castings Intrepid Flexburn

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New Member
Apr 4, 2022
Brunswick, Maine
Hello, joined up just to pass along some of our complicated experience with our 2020 Intrepid Flexburn. Apologies if this should have been tagged to another thread, but these comments apply to topics on several different discussions. First, this is our 2nd catalytic Intrepid and these were both installed in a reworked fireplace . We removed extended hearth, removed fireplace damper and lined proper-height masonry chimney with a 6" solid stainless steel liner . Later added a directional (wind-vane) chimney cap to try to improve draft. We still have a larger flexible oval pipe section (with cleanout at bottom) to connect stove outlet (horizontal) to chimney that probably causes some eddies in the exhaust flow and a simple 6" elbow would probably be better.

We did not insulate around the SS liner but did a load of work here to make a safe, proper fireplace conversion (photo) and this worked fine with our previous Intrepid.

Our problems with this new stove have been mostly around draft; I feel that to provide enough suction to pull draft all around the passages of this design will require a very strong draft compared to other stoves. Our old Intrepid worked fine, with little smoke escaping when loading through the top, and we were able to open the doors and use screen without smoke coming into the room; old screen fits the new stove, BTW, but not enough draft to burn with doors open and VC doesn't recommend that.

This is our 5th VC stove and we are big fans. This model is the only one short enough for fireplace installation with top loading and is just fine for our 1,500 SF house with fairly open plan; we heat about 60% with wood in our 7,000 degree-day climate. The Midnight finish (a powder coating rather than porcelain) is excellent and no chipping worries. So we want to make this install work well.

We worked with the customer service and tech folks at Hearth & Home Technologies (parent company) for months to try to improve things as well as offering some suggestions for changes in design and operating instructions. One thing that did reduce draft was a poorly fitting flue collar casting and we were sent a new one under warranty. Any leaks in flue will reduce draft reaching the stove.

Took the plenum apart in rear to verify that air shutter was working right, vacuumed a little ash in there. A second shutter opens when you close damper to provide more air through the combustion path.

I find the catalyst needs cleaning often and the little holes in back of firebox as well, all much easier than pulling the catalyst in previous stoves. The other accessible passages in stove are cleaned by vacuuming maybe twice a year. I still do not understand how air flows INTO the firebox and am concerned that some blockage there contributes to the insufficient draft problem--how does air get into the ash pan area?

We added the mentioned directional chimney cap for most pull up there, considered adding a section of chimney pipe but height specs are good now and would rather not have another couple feet of pipe in the air, which would be cold and so condensing smoke most quickly. The stove works a little better without catalyst, but I wanted the cat for: 1)less wood used 2)less pollution and 3)less stuff collecting in chimney.

Otherwise I have considered connecting outside air intake, which is made easy by the plenum connection at rear. Anyone have experience with before and after outside air intake?? Our house is getting tighter with weatherization work and providing combustion air is probably never a bad idea, esp with tighter houses and furnaces which are not sealed combustion.

Van Twisk VC Intrepid (5).JPG

Kevin Weis

Minister of Fire
Mar 3, 2018
Union Bridge, Md
Been a year or so since I last posted here on this but I still have the Intrepid Flexburn and actually is in use today with a small fire. As has been said above and I heartedly agree it is a draft needy stove. I have about 25' of 6" stainless steel liner inside of a Masonry chimney. What doesn't help with this is that I have about three feet total of horizontal run between the stove and the 6" liner. Masonry part of chimney is 12" thick in itself though. I think scooting the stove a foot closer to the vertical liner will help with this a great deal. The draft hungryness is caused by the downdraft exit design of the draft pull. This goes against what mother nature wants to do with the rising heated gases. Also the Intrepid has a secondary "bypass" draft to help insure adequate draft to the chimney. But I believe this also weakens the draft through the stove. I've put a separate control on this bypass draft which seems to help the airflow through the stove. Also running it without the cat will help with the airflow through the stove. The metal cat clogs up too easily with ash with the smaller holes.