PE summit and pacific owners have been holding out on us.

[Hogwildz]

I have a PE Summit insert and have been struggling with poor heat output since it was installed in November 2007. I have a 6-inch full SS liner and a blockoff plate with ceramic fiber insulation above the plate. Origonally, I was using outside air, but determined that the insert was sucking in cool air into the plenum area and blowing cooler air (85-90 F) out the front. I plugged the outside air and removed the knocked out on the side and now the insert is blowing air out at a max of 115 F (better but still not good).

I can only get the insert to a maximum temp. of 540 F (taken above right corner of door). I have tried different wood (seasoned oak purchased and from friends, compress sawdust logs and kiln dry wood from the store). I can get a good fire, but poor heat output. I think my insert is overdrafting, but I have no good solution.

From my experience, over drafting will cause it to run hotter & burn faster. Not cooler.
If your top temp has been 540, something is seriously wrong. When are you cutting the air back? How tall is the chimney? If you gained hotter output after going with inside air. Thats a start.
Are you by chance shutting the air down too soon?

 

[Hogwildz]

I appreciate your replies and I will continue to work with it, so far your suggestions are helping and the stove is working better.

Draft is absolutely not a problem.

I'm still trying to figure out a thermometer or heat gun to buy and where to mount it - what temperature are you guys measuring?
interior firebox? stove pipe at the outlet of the stove?
surface (magnet type thermometer) temp on the top of the stove?


I still want to try the inside combustion air idea - and / or run a pipe / duct from the bottom of the stove to the outside and pack the rest of the passage way
(old ash clean out, roughly 8"x8") with insulation to prevent all that cold air from cooling down the stove and the room.

Milner,
If your drawing combustion air by the old ash cleanout with no piping, then thats if not the main problem a majority of the problem, that unchanneled and free flowing cold iar is not intelligent enough to just flow to the stove air intake and nowhere else. Your flooding around the insert with cold air, and as you know into the room also.

 

[milner351]

Hog -- I'm trying to find out the dimension of the air intake slot for the insert - so I know what diameter pipe to run to feed the stove inlet without choking it.
(I suppose as long as the pipe doesn't contact the stove - I could use PVC?)

then I could pack the rest of the large opening with fiberglass insulation to seal off that cold air from cooling the bottom of the stove, and finding its way into the room.

I'm intrigued by the block off plate idea, but I'm not sure how well it will work in my case - my chimney had a heatilator set up in it when we bought the place - you know - the double sheet metal plenum with the vents on each side of the fireplace opening, 2 low, 2 high - supposed to heat the room via convection / conduction moving cold room air through the plenum.

The contractor we hired to install the liner removed the original damper assembly and cut a hole large enough to get the liner through to the stove - the hole is larger than the liner by a couple inches all around --- should I try to find perhaps a duct work 8" outlet flange to use to seal off the remainder of that opening?

 

[Jodi]

From my experience, over drafting will cause it to run hotter & burn faster. Not cooler. If your top temp has been 540, something is seriously wrong. When are you cutting the air back? How tall is the chimney? If you gained hotter output after going with inside air. Thats a start.
Are you by chance shutting the air down too soon?

The chimney is about 18-20 feet tall, but I have a corner fireplace so that adds another 5 feet of SS liner at a slight incline towards the chimney. I have been shutting the air half way when it gets to 300 F and then shutting it almost all the way when it gets to about 475-500 F. If I shut it down all the way at 475-500 F, the temp. will slowly drop down.

I can always get a good fire going. When the air is fully open, the flames will pour up and over the baffle. I had a glowing flue pipe once when the temp. on the insert was only a little over 500 F. This was confirmed with a second temperature gauge. Now, I keep 2 temp. gauges on the insert at all times above each corner of the door.

 

[rg500930]

myself i wouldnt want a cold air intake like that.the air would be coming in really cold at the insert.the air opening for the baffle is at the back of the insert.that would make the baffle run cooler.also the ebt is there.it runs just like a thermometer.it would also run cooler and different.as for the 8" pipe.myself i would slide a insulated 6"pipe into the 8" .double walled .this way you know its not the chimney and not wasting time,wood etc.8" could give you more or less.dont know.all i know is the stove was made to run a 6".
and shamong you have to run it hottter at first.if you see 700 or so dont worry.
heres a quick question to everyone.talking about temps.what is the highest anyone has seen on there summit?

 

[milner351]

Well,

I'm learning -- thank you to all for your input.

Here is the latest revision to my summit insert - I figured the intake slot area in the bottom rear of the stove to be ~1/4"x3" or ~.75in^2, so, I used a 1.5" pvc pipe as the inlet which has an area of 1.77in^2 for a bit of insurance (and I had a sufficient piece laying around).

I cut 2" foam (had it laying around too) to fill in the remainder of the 7.5"x 7.5" passageway that's roughly 18" deep.

The foam pieces are the full length of the passage - so, in theory, I've made a "duct" out of the passage.

We'll see how this works - it's going to be another single digit night here in SE Michigan - let's hope this helps that summit run like all the folks here tell me it can!

I want beach party warmth in my den!

 

[Hogwildz]

Hog -- I'm trying to find out the dimension of the air intake slot for the insert - so I know what diameter pipe to run to feed the stove inlet without choking it.
(I suppose as long as the pipe doesn't contact the stove - I could use PVC?)
I wouldn't use PVC, it will get warm behind that stove and possibly melt the PVC. Go with some 3" alum or galv. Just a suggestion, thats what I would do anyways. Plastic just melts far too easily. You would prolly be ok with fiberglass. ON the outside I would cover it with pressure treated or better yet a galvanized plate.


then I could pack the rest of the large opening with fiberglass insulation to seal off that cold air from cooling the bottom of the stove, and finding its way into the room.

I'm intrigued by the block off plate idea, but I'm not sure how well it will work in my case - my chimney had a heatilator set up in it when we bought the place - you know - the double sheet metal plenum with the vents on each side of the fireplace opening, 2 low, 2 high - supposed to heat the room via convection / conduction moving cold room air through the plenum.
I have the same exact fireplace. Block off those openings, they are yet another place for cool/ cold air to circulate. Previous owner blocked mine with plywood. Its still in place
If you dont have a big space around the liner, just close it off with whatever sheet metal you have/want to use. Just get that sucka closed off.

The contractor we hired to install the liner removed the original damper assembly and cut a hole large enough to get the liner through to the stove - the hole is larger than the liner by a couple inches all around --- should I try to find perhaps a duct work 8" outlet flange to use to seal off the remainder of that opening?

Yeap that'll work. Use furnace cement to seal the gaps between the two and done

I would seriously suggest closing off the outside air ash cleanout intake completely, and going with the knock out on the side.

 

[Hogwildz]

From my experience, over drafting will cause it to run hotter & burn faster. Not cooler. If your top temp has been 540, something is seriously wrong. When are you cutting the air back? How tall is the chimney? If you gained hotter output after going with inside air. Thats a start.
Are you by chance shutting the air down too soon?

The chimney is about 18-20 feet tall, but I have a corner fireplace so that adds another 5 feet of SS liner at a slight incline towards the chimney. I have been shutting the air half way when it gets to 300 F and then shutting it almost all the way when it gets to about 475-500 F. If I shut it down all the way at 475-500 F, the temp. will slowly drop down.

I can always get a good fire going. When the air is fully open, the flames will pour up and over the baffle. I had a glowing flue pipe once when the temp. on the insert was only a little over 500 F. This was confirmed with a second temperature gauge. Now, I keep 2 temp. gauges on the insert at all times above each corner of the door.

Still seems like maybe a draft issue. 5' of horizontal pipe is a long way. Have you checked for buildup lately? or even at the start?
whats the sixe of the chimney liner? I assume your just tapped into it, with no s.s. liner up the center to top?
One other thing, I know alot of folks swear their wood is ready, but I see it here even whe the ol lady picks some unripe wood. Takes forever to get temp up and anything below 600 it will cool down some and then take a long while to dry and start creeping back up to normal.

 

[bokehman]

Common sense would dictate that a larger pipe exhausts a larger volume. With that larger volume less heat is being kept in the fire box and more out to the environment. [...] Larger pipe is less back pressure, which in theory is not holding as much pressure and heat in the firebox. Again in theory. I know no back less back pressure sucks on my hawg

Well your explanation might seem like common sense but it's not true. The quantity of air passing through the stove is limited on the intake side by the damper. That restriction is minute compared to any restriction offered by a 6" stovepipe. The only other factor governing how much air the stove consumes is draft (i.e. the level of depression across the intake damper). Unless we are near the flow limit of the stovepipe (the sound barrier) a smaller stovepipe is alway going to produce better draft because to shift a fixed quantity of gases (limited by the intake damper) it needs to flow at a higher velocity. In the case of 8" and 6" stovepipe that velocity difference is 1.77x in favour of the 6" stovepipe ( (8^2) / (6^2) = 1.77 ). As for back pressure it only exists when the exhaust is the flow limiting restriction which in this case it is not.

 

[milner351]

Thanks guys.

At the moment I'm having a hard time finding furnace cement and high temperature insulation (rockwool, kaowool, roxul, etc).

The one local stove / hearth store I know of does not have the high temp insulation and was out of furnace cement, the big box stores carry neither.

I did stop by a heating / cooling place - after describing what I was doing - he gave me a good sized scrap of sheet metal to make a block off plate - but he didn't have any high temp insulation either.

So far the insulation and pipe in the ash clean out don't seem to be having much effect. Over the weekend I hope to:
- get the block off plate installed
- double check that there is insulation between the insert outer sheet metal housing and the masonry across the back, sides, and top
(using high temp stuff above the block off plate if I can find any)
- try the indoor combustion air.....
(but that means I have to remove some of the insulation between the liner and the masonry to give the air a path from the bottom intake to the side knock out)

I will take some pictures to give you guys an idea of the installation - and I'll probably run it a while with the front panels off just to make sure all is well.
The temps are supposed to be 30+F so, letting the stove cool down a little shouldn't be too bad.

 

[Hogwildz]

Sounds like your on the right track. Let us know if any/no improvement?
I have same insert & same fireplace it sits in, and its toasty in the whole house here.
Of course every set up is not the same. Just hope you can find the answer.
There are enough happy warm Summit owners in here that makes me think its something other than the stove itself.
If it was VC "neverburn" I could understand.

 

[Hogwildz]

Common sense would dictate that a larger pipe exhausts a larger volume. With that larger volume less heat is being kept in the fire box and more out to the environment. [...] Larger pipe is less back pressure, which in theory is not holding as much pressure and heat in the firebox. Again in theory. I know no back less back pressure sucks on my hawg

Well your explanation might seem like common sense but it's not true. The quantity of air passing through the stove is limited on the intake side by the damper. That restriction is minute compared to any restriction offered by a 6" stovepipe. The only other factor governing how much air the stove consumes is draft (i.e. the level of depression across the intake damper). Unless we are near the flow limit of the stovepipe (the sound barrier) a smaller stovepipe is alway going to produce better draft because to shift a fixed quantity of gases (limited by the intake damper) it needs to flow at a higher velocity. In the case of 8" and 6" stovepipe that velocity difference is 1.77x in favour of the 6" stovepipe ( (8^2) / (6^2) = 1.77 ). As for back pressure it only exists when the exhaust is the flow limiting restriction which in this case it is not.

Ummmm. ok I'll take your word for it. But I can't fathom what sound barrier has to do with any of this.
A lil too deep for me.

 

[milner351]

Hog

it's good to know that you have the same "heatilator" type set up.

Do you have any install pictures you could share?

Is yours in an outside chimney?

Did you use insulation around your insert?
(not blocking the air path from the inside air knock out to the stove inlet at the base will be a bit tricky)

At least the heatilator is metal - so sheetmetal screws should be sufficient to hold the block off plate into place....
the question is can I get the drill up in there with the insert in place --- I'm hoping to do this with heat gloves on without removing the insert.

 

[karl]

Common sense would dictate that a larger pipe exhausts a larger volume. With that larger volume less heat is being kept in the fire box and more out to the environment. [...] Larger pipe is less back pressure, which in theory is not holding as much pressure and heat in the firebox. Again in theory. I know no back less back pressure sucks on my hawg

Well your explanation might seem like common sense but it's not true. The quantity of air passing through the stove is limited on the intake side by the damper. That restriction is minute compared to any restriction offered by a 6" stovepipe. The only other factor governing how much air the stove consumes is draft (i.e. the level of depression across the intake damper). Unless we are near the flow limit of the stovepipe (the sound barrier) a smaller stovepipe is alway going to produce better draft because to shift a fixed quantity of gases (limited by the intake damper) it needs to flow at a higher velocity. In the case of 8" and 6" stovepipe that velocity difference is 1.77x in favour of the 6" stovepipe ( (8^2) / (6^2) = 1.77 ). As for back pressure it only exists when the exhaust is the flow limiting restriction which in this case it is not.

Ummmm. ok I'll take your word for it. But I can't fathom what sound barrier has to do with any of this.
A lil too deep for me.

I agree Hog, that is a little too deep. I do undertstand what he's talking about. When the flow of air in a plenun reaches the sounded barrier it does stop flowing and produces pressure waves and cavitaion. I can't see how this would happen in a stove. It usually happens in a engine when the valves are almost completely closed. That's why roller cams were developed, so you can have a steeper profile on the cam to minimize this.

 

[Hogwildz]

Hog

it's good to know that you have the same "heatilator" type set up.

Do you have any install pictures you could share?
Yes, but will take me a lil while to postem.

Is yours in an outside chimney?
Used to be outside, then addition was added on , so now its inside

Did you use insulation around your insert?
(not blocking the air path from the inside air knock out to the stove inlet at the base will be a bit tricky)
No, I myself don't see much benefit of this. I want air flowing. And being the chimney is now all but the top 8 foor or so inside, I like the fact I get the masonry holding & releasing some heat.

At least the heatilator is metal - so sheetmetal screws should be sufficient to hold the block off plate into place....
the question is can I get the drill up in there with the insert in place --- I'm hoping to do this with heat gloves on without removing the insert.

LOL, my brotha, I did it cold, and used a right angle frill attachment for my cordless. It was a REAL PITA, but doable. I had about 4 inches I think to work. I took the top front gray part of the insert casing off.
I suggest pre drilling holes in the plate and you can use them as guides for self tapping screws to go into the heatilator steel.
Since I installed a full block off plate, I had flanges bent downward to fasten sideways into the heatilator box. Then a few upwards to screw the 3 pcs of plating together. I used 3 pcs to make up the block off plate.
I have since donw them with 1 pc, as tight as possible to the liner, then a tight fitting ring around to close the gap around the liner and block off plate. This way worked much better.
Basicallly, however you can get it in there, and get it fastened, is a good way
I have yet to find a very easy way. Its tedious and required a lil patience, which I lack.

 

[milner351]

Understood! I'll have to drink decaf tomorrow morning! ;-)

Yea, taking off the upper front "sheet metal" of the insert maybe a must for drill motor clearance.

I have a large enough piece of sheet metal to make the plate out of, I'm probably going to make two pieces with U shapes cut out of them to fit around the insert, then overlap each other, then put the "flange" to make the final seal to the liner - with furnace cement that I still have to find.

So far no luck with the high temp insulation -- so I may end up going without - and relying on the sheetmetal alone to do it's job.

 

[Hogwildz]

Understood! I'll have to drink decaf tomorrow morning! ;-)

Yea, taking off the upper front "sheet metal" of the insert maybe a must for drill motor clearance.

I have a large enough piece of sheet metal to make the plate out of, I'm probably going to make two pieces with U shapes cut out of them to fit around the insert, then overlap each other, then put the "flange" to make the final seal to the liner - with furnace cement that I still have to find.

So far no luck with the high temp insulation -- so I may end up going without - and relying on the sheetmetal alone to do it's job.

I went without the insulation. Non readily available, and figured with top plate & block off plate= dead air space acting as an insulator. For me anyways, the heat lost to the lower block off is minimal, and I don't notice nor miss it.
Furnace cement should be readily available at any local ACE or hardware store for that matter.

 

[bokehman]

Hog, What I'm saying is it is only when the 6" tube starts restricting flow that an 8" tube will flow better. With a woodstove the exhaust never restricts the flow so the only difference between the two is the exit velocity.

I can't fathom what sound barrier has to do with any of this.

The sound barrier is the highest velocity that gases can pass through a tube, i.e. once reached the only way to flow more gas is to use a bigger tube.

 

[milner351]

Well,
I've tried a couple of things - neither seemed to have much effect.

1. I blocked off the outside air inlet and opened the knock out to run inside air --- made no difference that I could tell in heat output -- it may have warmed up the stove bottom some - but it's difficult to tell.

2. I pulled the insert out of the fire box a couple inches - this allowed me to get regular non faced fiberglass insulation between the insert outter sheetmetal - and the sheetmetal of the old heatilator firebox.
-- this SHOULD make a big difference in preventing heat loss to the exterior masonry.
HOWEVER -- I now can't get the stove back in far enough to slide the trim panel flush with the fireplace surround so, at least some of the insulation on the back of the stove will have to come out.

a couple more ideas:

-what about pouring vermiculite or some type of loose fill high heat insulation material between the two steel layers of the old heatilator ???
I would imagine this would do a good job of blocking heatloss from the stove to the exterior chimney?

-I think the simplest option for a block off plate is to order some rock wool type insulation over the web and install it around the liner to seal it off and stop the flow of hot air up the chimney.

(high temp insulation is not available locally after checking many stores, so,
I took the stove apart hoping I could make a sheet metal block off plate -- not with my limited sheet metal skills and tools -
thanks to the old heatilator steel inside the chimney (double wall) and the way the installer of the stainless liner cut it up and removed the damper
- there is little I could do with what I have on hand, and I'd need a lot more sheet metal to create a horizontal block off plate flush with the fireplace opening.)


any suggestions of online sources for roxul, rock wool, kaowool, etc???
what about loose fill insulation?

 

[Jodi]

Well,
I've tried a couple of things - neither seemed to have much effect.

1. I blocked off the outside air inlet and opened the knock out to run inside air --- made no difference that I could tell in heat output -- it may have warmed up the stove bottom some - but it's difficult to tell.

2. I pulled the insert out of the fire box a couple inches - this allowed me to get regular non faced fiberglass insulation between the insert outter sheetmetal - and the sheetmetal of the old heatilator firebox.
-- this SHOULD make a big difference in preventing heat loss to the exterior masonry.
HOWEVER -- I now can't get the stove back in far enough to slide the trim panel flush with the fireplace surround so, at least some of the insulation on the back of the stove will have to come out.

a couple more ideas:

-what about pouring vermiculite or some type of loose fill high heat insulation material between the two steel layers of the old heatilator ???
I would imagine this would do a good job of blocking heatloss from the stove to the exterior chimney?

-I think the simplest option for a block off plate is to order some rock wool type insulation over the web and install it around the liner to seal it off and stop the flow of hot air up the chimney.

(high temp insulation is not available locally after checking many stores, so,
I took the stove apart hoping I could make a sheet metal block off plate -- not with my limited sheet metal skills and tools -
thanks to the old heatilator steel inside the chimney (double wall) and the way the installer of the stainless liner cut it up and removed the damper
- there is little I could do with what I have on hand, and I'd need a lot more sheet metal to create a horizontal block off plate flush with the fireplace opening.)


any suggestions of online sources for roxul, rock wool, kaowool, etc???
what about loose fill insulation?

You can pick up a 4' X 8' sheet of 24 gauge sheet metal from a local HVAC supply store for about $20.00. If you have a template, they may even cut it for you.

I picked up ceramic fiber blanket insulation from McNeil, Inc. in Robbinsville, NJ - www.mcneilusa.com. It costs about $2.15 per sqaure foot, but you need to purchase 50 square feet. I put 3-inches of it on top of my block-off plate. I think they have a loose fill ceramic fiber insulation as well. I believe they will ship materials (1-800-722-5538).

Also, I believe Empire Refractory sells ceramic fiber insulation online - (broken link removed).

 

[milner351]

Thanks Shamong, I'll look into your suggestions.

I have a lead on some kaowool insulation from a guy in Grand Rapids on Ebay.

What does everyone think about trying to fill the air space between the two layers of the heatilator sheet metal with some kind of loose fill insulation, shoved in fiberglass battes, or even sand, to try to keep the heat inside the exterior chimney as much as possible?