# Options with existing masonry hearth and chimney



## activa (Feb 21, 2020)

So this is a bit complicated, I'll describe the situation as accurately as I can.

I own a home that is a duplex up/down. My father (85) lives on the first floor. The home has an existing masonry chimney with an 8" x 12" clay lining. There are two appliances currently using the flue: a pellet boiler in the basement and a wood stove on the first floor. The wood stove is on a lovely large granite hearth which extends into the room and up the wall. The thimble into the flue for the wood stove goes through this hearth wall.

I would like to replace the existing wood stove with a gas appliance, for reliability, safety, and ease of use (we get the occasional power outages her in Maine). What are my options? I'm considering just using a ventless stove since the use is primarily as an auxiliary/backup heat source. But the local propane company is balking at setting tanks because Maine is considering banning the use of the ventless devices.

My other option is to install a direct vent unit, but I would have to run b-vent up the existing flue, and then that would require an additional stainless vent for the pellet boiler. The granite hearth is large and it would be silly to leave it empty and move the location of the stove, and I'm not going to remove the hearth.

Any opinions or thoughts or other possible options? Maybe put a gas log set in the existing wood stove? But that's quite inefficient, right?


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## DAKSY (Feb 21, 2020)

Have you considered moving the pellet vent & install a Direct Vent (DV) 
appliance, whether it be an insert or a stove. 
Either one will heat THAT room & maybe more if you get a big enough unit.


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## activa (Feb 21, 2020)

Thanks for the idea. If you mean the pellet boiler in the basement, THAT unit is a large boiler hooked up to a HUGE (8' x 8') pellet hopper... so no, that's not possible.  My system looks like this, only the hopper is even bigger and made of OSB.


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## bholler (Feb 21, 2020)

activa said:


> So this is a bit complicated, I'll describe the situation as accurately as I can.
> 
> I own a home that is a duplex up/down. My father (85) lives on the first floor. The home has an existing masonry chimney with an 8" x 12" clay lining. There are two appliances currently using the flue: a pellet boiler in the basement and a wood stove on the first floor. The wood stove is on a lovely large granite hearth which extends into the room and up the wall. The thimble into the flue for the wood stove goes through this hearth wall.
> 
> ...


Why if you are removing the wood stove that has a chimney would you not just use that chimney to vent the gas stove?  I home they do ban ventless units they really are not a good option at all


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## activa (Feb 21, 2020)

Direct vent stoves require b-vent. I can run b-vent for the propane stove but I would have to also run a second vent for the pellet boiler, which has to be stainless because it shares the flue and the smoke is acidic. So I'd have to run two separate vents.

Why do you dislike the ventless units? We have two ventless gas fireplaces we use for backup heat all the time. It's a great option when the power goes out.


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## DAKSY (Feb 21, 2020)

*Direct vent stoves require b-vent. *

That statement is incorrect. B-Vent is COMPLETELY different from Direct Vent. BV is ONE pipe & relies on natural draft, while using combustion air from inside the home. Direct Vent draws combustion air in thru one part of the venting configuration, whether it is co-linear or co-axial. & exhausts out the other.


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## bholler (Feb 21, 2020)

activa said:


> Direct vent stoves require b-vent. I can run b-vent for the propane stove but I would have to also run a second vent for the pellet boiler, which has to be stainless because it shares the flue and the smoke is acidic. So I'd have to run two separate vents.
> 
> Why do you dislike the ventless units? We have two ventless gas fireplaces we use for backup heat all the time. It's a great option when the power goes out.


I dislike ventless units because they are not ventless at all they simply vent into the house.  They also generally have limits on how long they can be used etc.  They are horrible for indoor air quality


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## bholler (Feb 21, 2020)

Also how does the furnace in the basement share a flue with the fireplace upstairs?


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## activa (Feb 22, 2020)

"That statement is incorrect. B-Vent is COMPLETELY different from Direct Vent"

I didn't say that direct vent was the same as b vent, I said that direct vent stoves require b-vent. Which is true in this case; the direct vent appliance requires a b vent to use the existing flue.

The masonry flue simply has two thimbles in it: one in the basement, and one in the first floor. It was a common way of doing it in the past.


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## DAKSY (Feb 22, 2020)

"I said that direct vent stoves require b-vent."

That is STILL wrong...
DV units CANNOT use B-Vent.
It's single wall, single pipe.
They require Direct Vent.
Single wall DOUBLE pipe.


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## activa (Feb 22, 2020)

Not if they are vented into an existing flue.





__





						Can a Gas Stove Be Vented Through a Fireplace Chimney?
					

Can a Gas Stove Be Vented Through a Fireplace Chimney?. Gas stoves produce carbon monoxide and other dangerous gasses during the combustion process. This exhaust must be safely vented outside of your home or it could cause illness and even death. It is possible, however, to vent a gas stove...




					homeguides.sfgate.com


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## DAKSY (Feb 22, 2020)

From your post - verbatim.

 "This type of system is called B-venting and is less efficient than direct venting."  

Believe me, you CANNOT hook a B-Vent unit to a DV system.
I have installed at least 100 DV units. 
They are COMPLETELY different from B-Vent.
It's obvious that you know more than I do,
even tho I have spent 12+ years of my life in the hearth industry, 
so I will let you go on your merry way. 
Good luck with whatever you decide to do.
I hope it works. An improperly installed gas unit will kill you.


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## activa (Feb 22, 2020)

Thanks for the input, no point getting snarky. I'm not an expert, you've got a lot more experience, but others have told me it can be done, and here's an adapter for the application: 

DVA5BV—Direct Vent Adapter to 5” B-Vent


			https://www.valorfireplaces.com/media/Generic%20Title%20PDF%20manuals/Bilingual/DVA5BV-E-F.pdf


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## bholler (Feb 22, 2020)

activa said:


> "That statement is incorrect. B-Vent is COMPLETELY different from Direct Vent"
> 
> I didn't say that direct vent was the same as b vent, I said that direct vent stoves require b-vent. Which is true in this case; the direct vent appliance requires a b vent to use the existing flue.
> 
> The masonry flue simply has two thimbles in it: one in the basement, and one in the first floor. It was a common way of doing it in the past.


Yes it was a common way but a really bad way to do things.  In that case I would just direct vent a gas unit through the wall next to the chimney.  Or reline the existing chimney with a 6" for the furnace and a 3 or 4 for the gas unit


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## activa (Feb 22, 2020)

Yep, that's where I'm currently at. The chimney is in the middle of the house, so I can't go through the wall. And I have to use stainless for the boiler since it's burning wood pellets, right? So I'm looking at a major project and expense. Vs. just putting in a ventless and capping the wood stove's thimble.


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## bholler (Feb 22, 2020)

activa said:


> Yep, that's where I'm currently at. The chimney is in the middle of the house, so I can't go through the wall. And I have to use stainless for the boiler since it's burning wood pellets, right? So I'm looking at a major project and expense. Vs. just putting in a ventless and capping the wood stove's thimble.


But if you just brick the old crock shut and use a ventless you will still have the pellet furnace vented into an old oversized clay liner and you will have a crappy ventless unit pumping exhaust into your house.  And I always run stainless for gas appliances as well.  Aluminum just doesn't hold up very long


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## activa (Feb 22, 2020)

Ok, done right the first time is time saved. So do you have a recommendation for the appropriate type of propane stove?


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## bholler (Feb 22, 2020)

activa said:


> Ok, done right the first time is time saved. So do you have a recommendation for the appropriate type of propane stove?


Either direct vent or b vent would work.  Direct vent would use the remaining space around the liners to supply combustion air.  B vent would just run to the chimney and connect to a liner.


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## activa (Feb 22, 2020)

Hey BTW I see you're in central PA, where? I grew up there, my brother is in Port Mathilda.


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## brenndatomu (Feb 22, 2020)

bholler said:


> you will have a crappy ventless unit pumping exhaust into your house


Yeah I don't understand how these things were legal in the first place...most people would replace a furnace with a cracked HX in a heartbeat, but that scenario would typically only be letting a small portion of the combustion gasses (CO) into the house...yet a ventless heater is putting ALL of the CG into the house!   
I had ventless gas logs here years back...always hated the smell and the moisture on the windows after running them for an hour...didn't get used much, replaced by a Drolet woodstove now!


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## activa (Feb 22, 2020)

But gas ranges are still legal... don't see that changing real soon.


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## brenndatomu (Feb 22, 2020)

Gas ranges are not typically going to be putting off near the volume of combustion products, or running near as long as a ventless gas heater will. Yeah I have heard of people trying to heat with a gas range, but that is certainly "off label" use...


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## Alexx (Feb 23, 2020)

Can you run a direct vent pipe up through the two floors and out the attic?

Or leave the wood stove be for looks and put a small Williams unit or something on an outside wall?


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