Searching For An Air Leak

[EastMtn]

Lately I've had to nearly max out the combustion fan on a med feed rate to get a complete burn and not overfill the burn pot in less than a day. Factory feed settings for my Piazzetta Sveva for P4 (P1-P5)are Feed rate of 7 (2min-12max) and fan 2410rpm (1500min-2800max). I'm running 5.4 feed and 2700rpm which means the stove is putting out heat well below its capability to maintain a good flame.

My flame has a u shape around the drop chute which makes me think that I've got an air leak there. Unfortunately you can't get caulk behind the drop chute outside of the burn chamber because the stove was riveted and assembled in a way that you can't get to it without removing the hopper and control board. The chute is placed in the room blower/heat exchanger space that pushes the heated air out to the room. This also makes me think the problem is exacerbated when the room fan is on high. I did a test and looked at the flame when the room blower is off versus on high and the flames "U' widens when on high. The chute is welded to the cast iron fire box with only one spot weld at the bottom. Also found a sloppy caulking job at the top of the drop chute.

Oh yeah and the hopper is supposed to be silicone and gasket sealed but found a few spots where the gasket had a gap or silicone sloppily sealed. Pics attached. Any thoughts?

 

[briansol]

I think a 2-point U is fairly common, actually. Mine does it too.

 

[EastMtn]

Then maybe the problem is elsewhere. I sealed up all of the gaps that I could find and I'm letting them dry right now before I turn the stove on. I cleaned the vent pipe about 15 days ago. I thoroughly cleaned the stove again. The OAK is unobstructed. I have no damper but the stove's fresh air intake pipe is occluded partially with metal by design. Dollar bill test was good on top and sides. Bottom had a gap but I believe this is the airwash.

While I was waiting for the sealant to dry I decided to tackle my reverse osmosis system leaks. Bad idea doing two projects at once. I now have twice the mess to clean up before the wife gets home.

 

[EastMtn]

Wow Sveva's looking much better. I turned the stove on after the silicone had dried and had to quickly restore the factory settings because my old settings were causing a flame out. The "U" is still there and the flame a little lazy but nowhere near as pronounced and a lot more heat. Video attached.

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[Harvey Schneider]

If the leaks are at a stationary metal to metal interface, you might be able to use a silicate muffler sealant to close it off. Forms a glassy material when exposed to high heat.

 

[EastMtn]

If the leaks are at a stationary metal to metal interface, you might be able to use a silicate muffler sealant to close it off. Forms a glassy material when exposed to high heat.

MUFFLER WELD® REPAIR & SEALER
Looks like its good for 1000 continuous heat. I'm sealing metal to cast iron on the drop chute. Would it still work?

 

[Harvey Schneider]

At 1000 deg F cast iron is just beginning to glow visibly in daylight. I don't run my stove that hot.
Surfaces would have to be wire brushed clean to get a good bond.

 

[EastMtn]

At 1000 deg F cast iron is just beginning to glow visibly in daylight. I don't run my stove that hot.
Surfaces would have to be wire brushed clean to get a good bond.

Thanks. My stove only gets up to around 650. We'll see if this fix lasts.