# B vent blues



## abaton6 (Oct 7, 2011)

I've got a Hearthstone b vent propane fireplace / stove.  I've got 4" flex vent inside a 6" metalbestos chimney.  The 4" goes all the way to the top of the inside of the cap. - 3".  It was 30 deg last night.  I lit it off, it would not vent, clicked off on safety after2-3 min.  I got advice from "the gasman" last January about putting the flex vent inside the 6" mb.  He said the mb was too big, it would not get warm enough to draft.  That sounds logical.  It's a great LOOKING stove, but if it won't draft, it's just a boat anchor.  Any ideas out there in gas land?

Thanx,
Ken in Vermont


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## DAKSY (Oct 7, 2011)

Take a look at the cap, or take the cap off & look to make sure there
are no obstructions. Take a can of wasp/hornet killer with you, just in case...


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## abaton6 (Oct 7, 2011)

Thank for the reply Bob.  I just did the install last week.  I wrapped the sides of the cap with 3/16" wire cloth to keep out the critters.  We have a lot of small chipmunks around here.


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## DAKSY (Oct 8, 2011)

Did you try a test running it for a short period with the glass off?
5 - 10 minutes *MAX*...
****Don't do this for too long as CO could build up****
Does it run ok? 
Is the intake is blocked & NOT the vent?


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## Fake coal burner (Oct 9, 2011)

Do you have the manual for stove? check make sure you have the right gas pressure  orifice size for you altitude. Clean the stove inside with logs out. Take a vacuum cleaner with hose clean. check all burner ports. clean intake and around the bottom of stove good. B vent will suck in lint or other stuff clean where air shuter gets it air with vacuum hose  replace log set as to instructions . before you put the glass back on light stove and see how it works if ok replace glass assembly. Might leave a window or door open for this test. Make sure gas is turned off stove is cold. Before cleaning.  
Did the flu pipe go in easy? No Tears wile puling it.
You did the same as I did on my flue pipe. Mine did the same thing as your stove is doing, Had the wrong orifice Jet size installed. Plus had some dirt and lint that got sucked in. Good luck.


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## abaton6 (Oct 9, 2011)

Didn't check the orifice yet, but it came from a home right around here, and they used it for years.  The intake is clear.  The flue is not torn.  It's an expandable metal flue,  I don't think it would tear easily.  

If I light this off and heat the 4" flue, with a small propane torch, ( the part that goes to the metal bestos thimble ), it will draft fine for hours.  BUT then the t stat shuts off the flame.  And then the flue cool down.  T stat turns flame on, no draft again.  Frustrating.


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## Fake coal burner (Oct 10, 2011)

How high is the flue from stove to top about. Can you post a picture of the set up. Is it a standing pilot light ? If it is it should keep the flu warm. Is the pipe connection to stove good and tight. If it was from around the area and working it should work for you.  Leave pilot lit and wait for about   15 minutes and do a smoke test or match lit test at the draft hood and see if draws inward. No exhaust fans running in the house bath cooking stove fans etc. crack a window in the same room as you stove is in and see if it work also.


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## abaton6 (Oct 10, 2011)

Tried it tonight.   Worked fine, but it's about 60 deg also.  I have the problem when the weather gets cold.  The flue seems to bring cold air in and chill the pipe down.  Then the flue is so cold, it won't draft.  Is this an inherent problem with a b vent appliance?  I don't see how it wouldn't be since when the flame is not on, it's wide open to the outside, and bringing cold air in.


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## Fake coal burner (Oct 10, 2011)

All my appliances are B-vent water heater, furnace and gas heating stove. Don't have a cold draft problem. My gas heating stove  flue is in an outside chimney. You will get some cold air coming in when not in use Not to where you will notice it. They vent when cold -20F no problem even with wind blowing with standard cap. I have some different stove manufactures for B-vent showing Diagrams and trouble shooting and so on in pdf file. I can send some links. PM me


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## Garjan111 (Oct 11, 2011)

Take the wire cloth off. When you shut it down it condensates and freezes over the 3/16 openings. This usually only happens on long runs.

Happens to me a lot. You would think the pilot would melt it but the heat must not get up there if no draft.

Hope this helps.

Gary


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## abaton6 (Oct 31, 2011)

Looked at it tonight.  20 deg, pilot on.  cold air pouring in, would not draft till I heated the inside portion of the flue pipe with a propane torch.  Unless I keep the flame lit at all times, I really don't see what more I can do here.  When the t stat shuts down the flame, cold air starts pouring in within a few minutes, then t stat calls for heat, flame comes on, won't draft.  Right now I've got the room closed off, and a rag stuffed in the flue to keep the cold air from coming in.  There are no fans exhausting air from the home.  No dryer running, no kitchen exh hood running, I even piped in combustion air for my pellet stove.

Any other suggestions?  Thanx


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## Garjan111 (Nov 2, 2011)

Is the 4" pipe sealed off at the top as to not let air down around it? How are you keeping air from coming into your house or around the pipe? Maybe put some insulation around the 4" at the top. Pics might be good.

Gary


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## Ehouse (Nov 7, 2011)

When the cold air comes in, where does it go?  Are there open cold air returns/registers pulling air into furnace ducting?  sounds like you have negative pressure in the house.

Ehouse


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## abaton6 (Nov 7, 2011)

Ehouse said:
			
		

> When the cold air comes in, where does it go?  Are there open cold air returns/registers pulling air into furnace ducting?  sounds like you have negative pressure in the house.
> 
> Ehouse



Thanks for your thoughts.  The cold air just gets dumped into the room through the vent pipe.  I don't have a furnace, or any registers.  The house doesn't have negative pressure.  I even piped in combustion air for my pellet stove to eliminate that possibility.


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## abaton6 (Nov 7, 2011)

Garjan111 said:
			
		

> Is the 4" pipe sealed off at the top as to not let air down around it? How are you keeping air from coming into your house or around the pipe? Maybe put some insulation around the 4" at the top. Pics might be good.
> 
> Gary



Thanks for chiming in.  The 4" is not sealed at the top.  I need to pick up some insulation, and do this.    I haven't figured out how to post pics here yet.


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## abaton6 (Nov 17, 2011)

OK, I sealed around the 4" flue pipe at the top.  No help at all.  All the same issues.  Discouraging.


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## Ehouse (Nov 18, 2011)

Huh.  The air coming in must be displacing air going out somewhere.  It's either being sucked out or pushed out.  Try closing that pellet stove air intake.

Ehouse


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## abaton6 (Nov 18, 2011)

The pellet stove is using outside air for combustion.  Weird.


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## Ehouse (Nov 18, 2011)

Could the outside air intake be blocked by something?  or maybe it's undersized.

Ehouse


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## abaton6 (Nov 18, 2011)

It's the correct size, and brand new.  I read somewhere that the first elbow in the flue pipe should be at least 10 times the flue diameter from the top of the stove.  I have a 4"  flue, and the first 90 is 36" from the top of the stove. m A bit short.  Then it goes through a 2' thimble, then up about 8'.


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## stoveguy13 (Nov 18, 2011)

is the stove in the basement?


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## abaton6 (Nov 18, 2011)

The stove is in a 12 x 14 bump out I built last year.  The ceiling goes from 7', to 5' 6"  high.


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## Ehouse (Nov 18, 2011)

If this is a tightly built house,  wouldn't you need intake air for both stoves?  B-vent uses inside air for combustion.

Ehouse


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## abaton6 (Dec 30, 2011)

OK update..   The 4" flex line that is inside the 6" metalbestos flue has no cap.  It simply ends 4" below the cap on the MB flue, and sealed around the side.  Do I need a special B vent cap attached to the 4" flex line?


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## DAKSY (Dec 31, 2011)

I don't think there is any need for a B'vent cap. It wouldn't
be any different than what you have there now. How much 
MB is exposed above the roof? I don't believe you have to adhere 
to the 10-2-3 rule with a non-solid burning appliance. I'm thinkin 
maybe if you removed a section of the Class A, you might not have
this issue, as there would be less cold metal to inhibit your draft...


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## abaton6 (Dec 31, 2011)

DAKSY said:
			
		

> I don't think there is any need for a B'vent cap. It wouldn't
> be any different than what you have there now. How much
> MB is exposed above the roof? I don't believe you have to adhere
> to the 10-2-3 rule with a non-solid burning appliance. I'm thinkin
> ...



Thanx Bob,

I talked to a hearthstone dealer yeterday, and told him about the outside MB chimney.  He also thinks that I have too much flue outside.  Mine goes through the wall then up about 8-10'.  He suggested putting vermiculite in between the flex pipe, and the MB pipe, insulating the flex line, and it may draft better.  He said it "could" work.  If not, I'd have to go through the roof, someting I was trying to avoid.  I'll post the results of the insulation fix.

Happy new year!


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## abaton6 (Jan 9, 2012)

Ok, I finally gave up on the b vent.  I think you really need an inside chimney to make it draft proprely.  Thank you all  so much for your input.  

I just bought a Vermont castings, Jefferson model DIRECT VENT.  We'll see how this works for me.  I put the Hearthstone on craigslist.


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