25-PDVC's Original Burn Pot......

[CladMaster]

is not very efficient !

Some background info on my setup...
25-PDVC corner install with OAK installed.
Exhaust vent -- EVL = 18 feet, this is broken down as follows
3" pipe from the stove to outside the house -- 1 stove adapter, 45 bend, 2 feet through the wall, cleanout T, 2 feet vertical, from there I have 5 feet of 4" straight up to the horizontal end cap as I needed to clear the top of the window on that side of the house by 1 foot.

The most talked about thing with this stove is the dirty sooty burn, the stove gets covered in black soot, including the glass. Those that own this stove, will, I'm sure chime in and comment on this.

The other thing that this stove is known for, is the lazy dark yellow flame, and this is part of the reason why the stove makes this black soot / ash, especially on the right side of the stove.

Then there is the issue with the ash, it clogs up the burn plate most of the time. You will see this in one of the pictures below with the original burn plate. Also, notice the color of the ash, it's brown / black and not white / grey !

A few months back, a member here re-designed a new burn pot holder and used a burn pot from another stove (See this thread here -- https://www.hearth.com/talk/threads/need-help-with-englander-25-pdv.118384/)

This gave me an idea, and a Research and Development Project took off ......

I wanted to use the original burn pot that holds the burn plate, so ......

For about a week I watched how the stove burned with all it's settings, the result was a lack of air getting to the pellets for a clean burn. I tried blocking off the side holes in the burn pot, this helped to a degree, but still produced a yellow flame with black tips to the flame, a sooty black burn.

Prototype 1
I then acquired a piece of metal the same thickness as the burn plate and set about making a new burn plate that was about two thirds of the original plate and blocking off the front section that slops up (see picture below). I tested this over 7 days, it was an improvement, but still it produced that black soot / ash that coated the inside of the stove. The fire still had a lack of air to burn the pellets cleanly.

Ash was getting ejected out, but it was not clearing the burn plate to allow air to flow through the fuel, this produced some nice clinkers !

This lead to ......

Prototype 2
I modified the burn plate from Prototype 1 so that it was smaller, now it did not sit in the burn pot, this lead to making a holding plate at the back, the smaller burn pot sits on this plate at the back of the stove inside the burn pot, this leads to a short drop just under where the pellets are fed into the burn pot, this drop is just enough to disturb the already burning pellets which in turn allows for the ash to be ejected out of the burn chamber. I enclosed this smaller burn plate around the sides (left, right and front) with some carefully cut metal (the same metal used to make the burn plate), so that the fuel was contained in a small area. All the gaps that allowed air to escape blocked off with rope gasket (rope gasket is a temporary thing until I get the burn pot welded up).

As you will see in the pictures below, the Prototype 2 now produces a cleaner and more efficient burn, the back of the stove is not black, the stove produces plenty of heat too. Ash gets ejected from the burn pot and out to the sides and front. The flame is a bright yellow without the black tips.

With the original burn plate I was getting black / brown ash and 'dirty burn', now I get white / grey ash and a 'clean burn' with the new designed Burn chamber.

I also managed to incorporate the igniter into the new chamber, so no manual start of the fire.

Prototype 2 is a two part design, the back plate and burn plate will be welded together and make one part of the burn chamber, the side plates and blocking plates will be welded together to make the second part of the burn chamber. It fits together in two parts. This allows for easy cleaning with a scraper.

 

[CladMaster]

Update -- 4 days on : I have not had to clean the stove out, it's been running 4 days none stop. I've been topping up the hopper without the need to shut the stove down, no black soot on the window, clean inside apart from the white / grey build up that you get on the glass that wipes off with a cloth. No clinkers, ash is thrown up and out of the burn chamber.

Ash is white / grey in color, flame is still a bright yellow with no black tips.

I have burnt 4 different pellet brands over these 4 days --- Natures Own, MWP, Pres-to-Logs and Heat Resource, not had a single issue with heat (lack off), or a clinker issue, or ash build up within the burn chamber.

With the original burn plate I would be cleaning the stove every 12 - 16 hours !

 

[Lake Girl]

Interesting modifications - have you sent a PM to stoveguy2esw (Mike from Englander)? Instead of modifying burn pot, would the burn have been better if it was 4" venting from the stove out?

 

[CladMaster]

I can not put a 4" vent through the wall, there are 2 support studs that are in the way due to the way the house was built, I had just enough room for the 3" vent with the thimble, and because I had to clear the top of the window by 1 foot it took me over the 15' EVL, so I finished it off with 4" venting. Also, the stove could not go elsewhere, the location that it's in was the only option.

 

[Lake Girl]

The surprise in a corner install! The Englanders don't have the reduction of clearance near windows with the OAK do they?

 

[CladMaster]

The Englanders don't have the reduction of clearance near windows with the OAK do they?

Nope, not that I have seen.

 

[Lake Girl]

Lucky you have the ability to modify and got a better burn - not everyone has the equipment and know-how to do it! Happy burning

 

[chrisasst]

How much are you selling one for? Or you could make me a tester and send me one...
I am in a need for something better..

 

[CladMaster]

It's in testing stage as of now (prototype not welded up), should be about a week or so with the tests. I'll get it welded once I'm happy with it and re-test it to make sure that I have got it right.

 

[chken]

How dare you mod your burn plate! Don't you know that the mfr has spent thousands of hours on a supercomputer designing those to work at optimum efficiency?!?



<sarcasm>

 

[CladMaster]

Well I guess the 'supercomputer' design (software) is also flawed, you'd think that a supercomputer would get it right the first time !

<sarcasm>

 

[stoveguy2esw]

now all you need is to shell out about 20 grand and have the stove tested for emissions with your new pot. make sure it will pass as it sits as if you have to take the stove down and do any mods to correct anything its another 10 grand to set it back on the stand and retest.

as for the pot , yeah its going to stay clearer as the same amount of air is being transited through a smaller chamber. used to be when you could sell 35-1 units anywhere you could have an unlimited air budget and not have to worry about the excess particulates that carry through the stove and into the exhaust stream as emissions were not tested in exempt units. nowadays the only things you can sell nationwide are cert units and to meet the cert qualifications you have to keep particulates below a certain amount, this is calculated by filters which catch particulates from sampling of the exhaust stream while the unit is running. now the filters are weighed before and after the test and the amount of particulates are determined in this manner (so to speak, its more complex than that) the filters do not differentiate between inert ash (fly ash) and other particulates so to keep the ash from becoming part of the sample you have to keep the air down enough to keep the fly ash out of the sample while still burning clean enough so as to not have unburned soot show up on the filters either. it aint easy.

making the pot eject ash and burn without ash loading isn't that hard, ive done this many times in different stoves in my lab, but making it do this and still get a certification is more difficult, and its going to get harder. the PDVC you are burnig is actually the highest GPH pellet stove we build, at 3.1GPH I think, we will have to have our products below 1.3GPH within the next 5 years. I aint looking forward to this as its gonna be quite taxing. this stove as we currently build it may not be available in a few years due to the new regs.

 

[chken]

Well I guess the 'supercomputer' design (software) is also flawed, you'd think that a supercomputer would get it right the first time !

<sarcasm>

I agree, it's the software, couldn't possibly be the supercomputer hardware. Garbage in, garbage out.

I like the mods. So it seems a little drop helps agitate the burning pellets, and bigger air holes add more air in the bottom, and fewer air holes in the sides, makes for a cleaner and better burn.

 

[chken]

as for the pot , yeah its going to stay clearer as the same amount of air is being transited through a smaller chamber. used to be when you could sell 35-1 units anywhere you could have an unlimited air budget and not have to worry about the excess particulates that carry through the stove and into the exhaust stream as emissions were not tested in exempt units. nowadays the only things you can sell nationwide are cert units and to meet the cert qualifications you have to keep particulates below a certain amount, this is calculated by filters which catch particulates from sampling of the exhaust stream while the unit is running. now the filters are weighed before and after the test and the amount of particulates are determined in this manner (so to speak, its more complex than that) the filters do not differentiate between inert ash (fly ash) and other particulates so to keep the ash from becoming part of the sample you have to keep the air down enough to keep the fly ash out of the sample while still burning clean enough so as to not have unburned soot show up on the filters either. it aint easy.

Thanks for the informative post. I recall reading somewhere that my stove mfr, Piazzetta had to lower its combustion air, to meet EPA requirements, which sounds exactly what you are talking about. The side effect is that the air wash is not as good, which is a common complaint for Piazzettas.

Of course, combustion air is an adjustable setting, ...

 

[CladMaster]

I like the mods. So it seems a little drop helps agitate the burning pellets, and bigger air holes add more air in the bottom, and fewer air holes in the sides, makes for a cleaner and better burn.

Yes, the small drop agitates the fuel that's burning which helps with the ash removal.

I'll post up some more pictures later, I plan to do a clean out tomorrow or Friday.

I'll also put up a video of it burning over the weekend.

 

[CladMaster]

now all you need is to shell out about 20 grand and have the stove tested for emissions with your new pot. make sure it will pass as it sits as if you have to take the stove down and do any mods to correct anything its another 10 grand to set it back on the stand and retest.

as for the pot , yeah its going to stay clearer as the same amount of air is being transited through a smaller chamber. used to be when you could sell 35-1 units anywhere you could have an unlimited air budget and not have to worry about the excess particulates that carry through the stove and into the exhaust stream as emissions were not tested in exempt units. nowadays the only things you can sell nationwide are cert units and to meet the cert qualifications you have to keep particulates below a certain amount, this is calculated by filters which catch particulates from sampling of the exhaust stream while the unit is running. now the filters are weighed before and after the test and the amount of particulates are determined in this manner (so to speak, its more complex than that) the filters do not differentiate between inert ash (fly ash) and other particulates so to keep the ash from becoming part of the sample you have to keep the air down enough to keep the fly ash out of the sample while still burning clean enough so as to not have unburned soot show up on the filters either. it aint easy.

making the pot eject ash and burn without ash loading isn't that hard, ive done this many times in different stoves in my lab, but making it do this and still get a certification is more difficult, and its going to get harder. the PDVC you are burnig is actually the highest GPH pellet stove we build, at 3.1GPH I think, we will have to have our products below 1.3GPH within the next 5 years. I aint looking forward to this as its gonna be quite taxing. this stove as we currently build it may not be available in a few years due to the new regs.

30K for tests ! Ouch !

So, Mike, why do these stoves (PDV/C, and others like it from Englander) burn lazy and dirty the way that they do, I see so many posts on here about it.

 

[stoveguy2esw]

mostly due to lower air allowance , its a bigger pot than many too so the larger the pot the more widely distributed the air, hence , lower velocity. biggest ting with the c model and its big brother the pdv is they really do need to be kept clean , especially the exhaust pathway. newer models we have designed like the pah, ep and ip have a smaller pot a top feed system and a more indirect exhaust pathway which traps ash even at higher velocity I the exhaust stream.

one thing to look at also, this unit was designed in the 90's and released in 1998 technology back then wasn't what it is these days, and the "certified" pellet stove was not as common on the market. However since then we have built in excess of 120,000 of this model alone, making it quite likely the most successful single model of pellet stove (by numbers) in north America. it flat out heats. its cheap and its easy to maintain. that stove alone is the biggest reason we have grown as far as we have in the last 20 years or so since I started with ESW.

that said, its older tech, a bit clunky compared to more modern designs. but like the old fishers still chewing up logs out there its effective in the one thing that matters. slinging heat. now that new regs are coming down the pike though , like I said she's only going to around in her current configuration for at most another 4-5 years, currently we are working on a "smartstove" replacement for her in our line. some of the designs look pretty promising , but we have to plan ahead to make sure what we field will be able to meet or exceed the coming standards or it wont be worth the effort

 

[CladMaster]

Ah, thanks for the info.

The stove has done what I needed it to do on the cheap, and that was to save $$$ and spend less in oil and heat the house at the same time. In the two seasons that I've used this stove it's done it's job and saved me over $1000.00 per season in heating the house.

The daily cleaning of the stove's burn plate and glass getting sooty was starting to get to me, I wanted to not have to clean it when it got choked up in the burn plate every 12 - 16 hours, this is why I have re-designed the burn chamber. I now have a cleaner stove on the inside and a better flame color (bright yellow) and a nice clean view window, and I've not had to shut it down in 4 days to clean it.

I've been watching the vent on the outside of the house, I now don't get black soot coming out of it. I see no sign of ash being ejected out of the vent either, I'm hoping that the ash is staying within the stove, and for the ash that does get into the exhaust vent, it is caught in the cleanout T / trap, I'll know more when I do the cleanout that's planned for tomorrow or Friday.

As for the PDVC .... now that you have said that the stove is going to be discontinued in 4 - 5 years, what's Englanders standing on spares for these stoves ...... 5 years, 10 years, 15 years ..... ?

 

[stoveguy2esw]

As for the PDVC .... now that you have said that the stove is going to be discontinued in 4 - 5 years, what's Englanders standing on spares for these stoves ...... 5 years, 10 years, 15 years ..... ?

we use practically every electronic part in that unit on other models, including the base circuit board , even if the stove is discontinued we will stock parts for quite a while. especially if the parts are still in demand , we are in the business of making money right? so why quit selling parts as long as there is a reasonable demand. the stoves which are already out there are "grandfathered" so they will still be legal to operate and will need parts to maintain over the years. so yeah, we'll support them as long as there is a reasonable demand for the parts we have pellet stoves we built in 1990 that we still can support for virtually any part even though the model might have been discontinued 20 years ago

 

[PoopieBritches]

This is definitely a common issue with these stoves for sure(burn pot). I too have tried several different things to increase the flow through the burn pot. To try and eject the ash. Steel wool in the large side holes under the wear plate, plugging some of the holes in the wear plate itself(nearest the door). Nothing I tried seemed to really provide any true benefit.
Kudos to Cladmaster for coming up with an idea, and more importantly, executing that idea.
My thoughts are that while your design will allow for longer burns between cleanings of the burn pot, it will likely be at the expense of faster buildup of ash in the heat exchanger and exhaust path. Thereby, increasing the frequency for complete shut downs for cleaning the exhaust, and heat exchanger. Just my thoughts, I may be wrong.
I had figured that the reason Englander makes it the way they do, would likely be emissions related.
I was thinking of modding the burn pot. Shorten the actual pot itself, make the wear plate set flat in the pot, and hopefully allow the incoming unburned pellets to actually push the spent ash off the front of the wear plate. Similar to what the Harman's do.
Tricky part is that there isn't a lot of room in front of, or bellow the burn pot.

 

[CladMaster]

Well, I did a shutdown today to clean out the stove after running for the last 5 days non-stop, I wanted to see how bad the ash buildup was in the heat exchanger area, to my surprise, it was like it would have been after a 12 - 16 hour burn.

I checked the exhaust flue and found a small amount of ash in the horizontal part (the through the wall part), the cleanout T had some ash in it, not as much as I was expecting, not even half full in the cap. Did a full clean, brushed out the exhaust pipes.

I said I'd post some more pictures (see below).



Above: This is part one of the two part design, you will see how this fits in the stove below.



This part holds the fuel on the burn plate, it sits on top of the burn plate as shown below.



Below is how the lower part sits inside the stove.



You will see that the side holes next to the burn plate have been blocked off with rope gasket in the above picture.



In the picture above, I have used rope gasket to block off the sides to stop air from leaking out. I have made the blocking plates, I just need to get it all welded so that I can do away with the rope gaskets.

I've recorded a video of the stove running tonight, I just got to resize it so that I can upload it to my Youtube site, will do this over the weekend.

 

[Chris_!]

This is a great idea

 

[DBCOOPER]

Would increasing the cfm of the exhaust fan make it burn cleaner using the factory burn pot?

 

[kofkorn]

It would burn cleaner, but you would be wasting a lot of extra heat sending more CFM's up the vent. Ideally, you have a lot of air movement through the pot and then slower movement through the heat exchanger, which is what the modified burn pot is doing.

 

[CladMaster]

Would increasing the cfm of the exhaust fan make it burn cleaner using the factory burn pot?

It would burn cleaner, but then it would also still have the issue of the ash build up on the burn plate, the factory burn plate is too big really. If the burn chamber was shorter in depth and sloped down instead of up, it might have burned better than it does in it's current factory form.

It would burn cleaner, but you would be wasting a lot of extra heat sending more CFM's up the vent. Ideally, you have a lot of air movement through the pot and then slower movement through the heat exchanger, which is what the modified burn pot is doing.

Spot on.