webby3650 said:
I can't speak for your brand of pipe, but we never have to use sealant. If everything is operating properly, no seal would be needed, any gap would simply suck some air, not smoke out.
You are right as long as the system is maintaing the proper draft at the stove like yours does.
Sucking air in thru the gaps reduces draft, & for some systems can cause problems. Like my basement install with a 30" horizontal thru the wall insulated pipe. Lifting 20 feet of cold air to get a draft started is tough with the horizontal pipe in my system, it takes some coaxing. But I've learned to deal with it & have CO monitors, just in case.
With catalytic's exhausting cooler temperatures, air leaks cool it down more, & if the long column of cool air weighs more than the warm air at the bottom ( at some point) it can cause the draft to reverse. Bringing cold air & CO down the stack & out any gaps.
So a tight system is good thing. Not that is has to be, but is more important with cooler exhausts (like burning on low with cats in some systems), long chimneys & cold outside air temps.
Straight up pipe all the way is best, any horizontal pipe is a "choke" on the draft.
Some system are more difficult to get a draft started than others, but once the fire is going, draft well.
Sounds like you have a good system like we all wish we had with out have to go thru the pains of double wall pipe with a good joint seals.
My BK manual calls for a minimum draft of .02" of water (using a water manometer). More is a good thing.