Venting a Pellet Stove in Existing Chimney?

[MarkF48]

I'm taking delivery of a pellet stove this week. I had planned on venting through a wall, but I have an existing masonry clay lined chimney I had used for a wood stove years ago that I'm thinking about as an alternative to going through the wall with a vent kit. From the pellet stove instruction book this appears doable and will provide a natural draft in the event of a power failure. The stove dealer had suggested/recommended lining the existing chimney with stainless piping. I'm not sure he is simply making this recommendation so he can sell the pipe for lining the chimney or if there would be an issue of drafting properly. The chimney is lined with 8" clay tile.

Wondering if anyone else has vented a pellet stove through an existing chimney and has it worked out OK.

 

[65fl]

We do this, no pipe liner, works fine.

 

[Bob Ha]

I had one installed in existing fireplace. They left the existing pipe and insatlled a stainless inside of it. Not sure if that was required but that's what they did.

 

[buckshot721]

My Quadra fire instructions say you can do both. But the dealer where we purchased it from, recommended we install a liner. The kit was around $250.00 and took less then an hour to do.

 

[Mickey_Fx]

That's the only we I've done it for the last decade. I've always used a flex SST pipe all the way up and out of the top of the chimney. One does need to make sure none of the exhaust can make its way back into the room. We currently have the chimney sealed off at the top.

Also wise if possible to use outside air for combustion.

 

[Egon]

The stove dealer had suggested/recommended lining the existing chimney with stainless piping./QUOTE]

Depends on the area of the chimney. If it is too large it will not keep vent gasses at the proper velocity for good draft.

The insurance company may also require the liner.

Strongly consider the liner.:thumbsup:

 

[Car Doc]

It will work no doubt especially if you at least go 5-6' up with some sort of exhaust pipe but seeing as how the pellet stove is a positive draft. (pressure)

You may not have much draft going up a chimney just dumping it in there there isn't much heat in a pellet stove exhaust a 3" liner/tube ran out the top would be fool proof imho. Now the stove wont work worth a flip if it has any back pressure so thats a consideration however you vent it. fwtw

 

[MarkF48]

Below is a screen shot of the manual (Harman pellet stove) regarding a chimney install. The chimney is in good condition with the clay tile liner, so according to the manufacturer an install without a liner should be OK. The stove dealer recommends a liner, as well as some of the posters here, so I'm still not sure which direction to head in regarding going into the chimney.
My alternative install would be about 72" of pipe at a 45 deg angle from the house wall to clear from under a porch roof and would be cheaper than the chimney liner.

 

[hawkeye08]

Stove shop told us that the liner is used to ensure no leaks and it is the right size (not too big). If your clay liner is in good shape, and not way big, sounds like it would work to just use it.

 

[slowzuki]

Big problem without a liner, with an exterior chimney, a pellet stove doesn't produce enough waste heat via exhaust to make the chimney draft well.

 

[clemsonfor]

Like a few others have said you need the heat to create draft or the cold outside air will be "falling" down the chimney causing possibly the exhaust to not leave but part to creep into the home. Possible not saying it will happen. A short starter pipe is better than nothing.

I put my wood stove insert inmy older fireplace with clay liners i had 2 and they were like 13x7 or something. The 2 of them togeather was to much for my stove that if lined uses an 8" liner. So the result was poor heat and a fire that was not as hot as it should be. One liner if you looked was blowing smoke the other nothing. When i got up there one was sucking the other was blowing, a constant circle effect coming in one liner and mixing in the area above the stove with exhaust and then exiting the other liner. NO smok in the house it just wasent pulling enough air throught the stove to get a good complete burn. Store told me to block off the liner it was sucking through, and it was fine.

My point to this is that to much area can negatively effect your stove.

 

[Car Doc]

My alternative install would be about 72" of pipe at a 45 deg angle from the house wall to clear from under a porch roof and would be cheaper than the chimney liner.

That is the best way Mark imho if it is feasible that will positively vent it and you wont be having back draft into the house from the masonry chimney which would be very likely.

 

[QueBota]

You can go without one if you existing liner is in good shape and small enough to provide a good draft.

I would go with the liner, relatively inexpensive insurance.

Dave

 

[tractordog]

No problems in my old house without liner. The guy who installed it ran a pipe about five feet up. Dont forget to vacum it every year.. dont ask me how i know to do that.

 

[sld]

I have been using a pellet stove for the last several years. Do NOT forget to put a clean out in the exhaust somewhere close to the stove. While very efficient, they are somewhat dirty and can get clogged.

The outside vent is very easy to install. That way you are pressurized all the way outside. If just vented into an existing chimney I would be a little worried about it drafting properly. I can grab my vent pipe 3 feet above the stove after it has been running all day and it's not too hot to the touch.

 

[bearcreek paul]

Is your chimney inside your house or outside.If it's inside you should be able to keep a good draft.If it's outside you might have warm it up a bit with a heat gun or hair dryer when starting it up in the cold weather,depending on how cold it gets in your area.

I been using a 6 in stainless liner for the last ten years,it gives a good draft,and it's cheap insurance against carbon monoxide.

And don't forget the carbon monoxide monitors.

 

[westcliffe01]

I ran a corn/pellet stove for 2 seasons. Despite what is said regarding these stoves being "direct vent" if you do that it will leave a nice big sooty mark on your wall, which most people will find unsightly.

The flue temperature on these stoves is a lot lower than a wood stove, probably too low to draft properly in a large masonry flue. A pellet stove will never provide enough heat in my opinion to warm a masonry flue adequately.

If you go with the liner down the masonry flue it is a much better situation. Much less thermal mass, no interruption from the stove all the way to the chimney cap, so the combustion blower can do its job in venting the flue gases. The vertical rise will also mean that if you have a power outage, the stove will safely vent and not spill smoke into the house. Smoke damage was quite common with pellet stoves when they came out and is one of the reasons why proper vertical flues are recommended.

 

[sld]

I ran a corn/pellet stove for 2 seasons. Despite what is said regarding these stoves being "direct vent" if you do that it will leave a nice big sooty mark on your wall, which most people will find unsightly.

The flue temperature on these stoves is a lot lower than a wood stove, probably too low to draft properly in a large masonry flue. A pellet stove will never provide enough heat in my opinion to warm a masonry flue adequately.

If you go with the liner down the masonry flue it is a much better situation. Much less thermal mass, no interruption from the stove all the way to the chimney cap, so the combustion blower can do its job in venting the flue gases. The vertical rise will also mean that if you have a power outage, the stove will safely vent and not spill smoke into the house. Smoke damage was quite common with pellet stoves when they came out and is one of the reasons why proper vertical flues are recommended.

Wow Westcliffe! Is that from the corn?

My pellet only stove is in the basement, goes up thru the ceiling and out the side of the house (chimney box for upstairs fireplace). I have not had any sooting issues on the outside in at least 8 years. Also, mine vents to the north side so it is into the prevailing wind.

That has to be from corn...I have heard that it is a little dirtier burning.

 

[cropdusting]

+1 on the Wow, westcliffe01. I run straight corn and a mix of wood pellets and corn from time to time and mine leaves no soot on the house and only a small amount noticeable (after about a month) on the ground. I have about 4 foot of total pipe length to get the vent outside. Code requires 12 inches away from the house in my area. If it matters I am running 4 inch pipe per code versus the standard 3 inch because I am at high altitude. I also have a FAK (fresh air kit) installed too.

I have had no experience with venting directly to a chimney so I really cannot comment with much insight on that, but knowing what I know about how the venting works on my stove I would strongly advise using a liner of similar diameter of the vent pipe. As others have stated the gasses are not that hot leaving the stove and rapidly cool not to far down the pipe, so natural drafting might be an issue if say your going from 3 inch to say 12 inch diameter chimney. As a matter of fact I can stick my hand into my exhaust pipe and leave it there for 30 seconds or more.

 

[MF1652]

Like everyone has said the most important part is to make sure you have enough draft to exhaust the gasses. We had a pellet stove put in which used the existing chimney from a former wood stove. It was venting straight up through three floors before it got outside. We didn't know it but the exhaust gasses were never hot enough to properly vent out. The creosote was forming on the chimney half way up because it was cooling down before it reached the top. This resulted in a chimney fire which ended in a total loss of the chimney. I never realized pellet stoves could cause creosote build up and a chimney fire, but I do now. It was an expensive lesson learned.

Keep the pellet stove chimney short and straight if possible to increase the draft effect and exhaust the gasses before they cool off.