Why no hopper gasket?

[spruce_goose]

Hi all. New to the forum.
I run a Napoleon NPI40 at home, and also work with an Endurance 50F at work.

I just finished my first time doing a thorough cleaning of the Napoleon (from outside air intake to chimney cap).

My question is: isn't there air bypass through the auger and hopper when there's no hopper seal? (Napoleon)
It seems there's big fuss made over the door being sealed really well (makes sense) but then there's an auger and hopper with no seal whatsoever (on the NPI40 that is).

So i'm wondering what the deal is? Do they just engineer it with a certain amount of bypass through the hopper expected? Is it worth rigging a hopper seal (seams like it'd be tricky to get it right).

Thanks all.

 

[johneh]

Welcome to the forum
The manufacturer decides if the stove needs to have the hopper sealed
Some do some don't. Bottom feed stoves almost always have a seal top feed no so much.
My stove has no seal and that does not seem to affect the operation. Wouldn't
be concerned if the hopper lid was not sealed if the manufacturer has not sealed it

 

[tlc1976]

I’m sure it’s depends on the stove. Mine doesn’t have one and there isn’t even a full ledge around the door. But it must be with the sealing of the auger and the resistance of the pellets it slows down air leakage to where it doesn’t matter. But I never leave the door open unattended in case for whatever reason I had a hopper fire.

Mine has a hopper door switch that will stop the auger for safety so I disabled it. Now I can load a bag and pack it full and not feel rushed before the fire goes out. The auger is so far down you’d have to try real hard to put a finger in it. I can also sit there with the door open and snap long pellets while the stove still runs normal. But the vacuum switch certainly works because if you open the firebox door it shuts the stove down in short order.

 

[Don2222]

Most newer stoves have a hopper lid seal. It is more of a safety feature to stop air from feeding a hopper fire. Usually air does not get thru to the burn pot because the pellets block the air. The older quadrafire pellet stoves with no hopper seal actually stop feeding pellets when the hopper is very low on pellets because the vacuum switch senses the air leak and shuts the stove down.

 

[spruce_goose]

Thanks all.
Kinda what I figured. I just started scratching my head a bit realizing there was an air-path through the auger/hopper. Stove seems to have plenty of oxygen now after I cleaned it. Part of me was wondering if it was too much. But a major improvement from the choked out lazy flames prior to cleaning!

 

[SidecarFlip]

Kind of is dependent on if the unit is negative draft or positive draft. If it's positive draft, the burn area is slightly pressurized and there is a chance the flame can travel up the feed auger and ignite the pellet hopper if the hopper door isn't sealed tightly.

If it's a negative draft, the combustion fan pulls the combustion air in and through the burn pot and exhausts it out the venting so if the hopper lid isn't sealed tightly, all that happens is, a tiny bit of air comes in through the hopper and exits through the auger and pellets and into the firebox. If I leave my hopper lid open with a partial load of fuel in the hopper, I can visually observe that air as it impacts the flame in the burn pot.

My unit does have a lid seal but it's only there to 'quiet' the unit somewhat, not really necessary.