can i drop my stove vent from 4" to 3"

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jo2fst4u

Member
Hearth Supporter
Dec 4, 2006
57
I have an older Earth stove mp35-50 pellet/corn. It's set up with a 4" outlet and i cant seem to find much 4" around here. the guy told me to get a bell adapter and drop it to 3" and it would be fine is this true? Also he said that i could just use double wall 3" pipe like the kind that is used on a water heater.
 
he is frankly a idiot.
b vent is aluminum lined, and well melt under the temperture of solid fuel exaust. (the kind for water heaters)
pellet vent is stainless steel lined, and is rated for 600* not 250* like b vent
you can reduce, but you dont want too. It puts undue stress on the combustion blower.
 
You know guys he might be partially correct. He definately cannot go 4-3 but the B-vent might be listed for that stove. I know that an Earthstove HP-40 was listed for use with B-vent. I called foul on an install that had the b-vent and when presented with the owners manual sure enough it said right there that B-vent was acceptable.

Note: Though this may be technically accepted in my professional opinion pellet vent (Type L) is what you need. It is my understanding that when these listing were made that the Type L was in development or something along those lines. It's kind of like how we've learned that lining inserts is the way to go as opposed to face seal installs.
 
Dug up the old WP50 manual pg. 3 specifically states that pellet vent must be used. Further than that it specifically states that B-vent aluminum must not be used. I also have an HP40 manual that states the same thing. Maybe the model I am thinking of is wrong. It's an honest story though, we inspected it, called foul, the AHJ got involved etc., etc. and they presented an install manual that stated it was kosher. I mean if I hadn't seen that manual I'd never say such a thing especially since we walked away from the encounter with egg on our face. I'll ask my boss which one it was and see if I can get a copy of the manual. I wonder if it was doctored? I did only read the one page and it was a photocopy. I wonder if ol' Shane has been had?
 
Ohh i dont mind egg on my face when im wrong, and i make mistakes all the time. I was out of character calling this guy a idiot, i just get fed up with people giving people advice that could kill there family,(not hearth.com, the joker the poster was talking about.) You could very easly burn your house down and your family with it. Not to mention reducing it which will build up more heat. That was the most irresponsibe advice i have heard in a while. So for starters, wrong or right, i take back the idiot comment. But THANK GOD he posted here and didnt install that gas vent.
 
Oh definately, and it's obvious that he does need the L-vent as opposed to B-vent. Everyone loses cool occasionally, I seem to remember a gentleman who burned his paint of his Lopi last year that I was a little harsh on.
 
Well i will get the L rated pipe. Hows this sound I and putting in the corner and hooking a 90 then a 3 foot pieace thur the wall thimbull and put a cap on it. do i really need to get the whole kit i seen at the big box stores? after it's all said and done it will stick out my wall about 2feet do i need more?

Jeff
 
Check the installation instructions to ensure you are a safe distance from windows, doors, and public walkways (usually 48"). Also you may want to install a house shield to keep ash from accumulating on the exterior.

Most importantly, take pictures and post them here so we can see your handywork.
 
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