EPA stove overfire... Any changes to regulations? Flue liner size change?

[sadpanda]

Background: https://www.hearth.com/talk/wiki/why-stoves-overfire-from-too-much-draft/

I'm having this problem.

Has the EPA addressed this in any way with the new 2020 standards? Is there some sort of cfm/btu/draft calculator that can be applied with some intelligence instead of blindly following EPA or simply throwing in a key damper?

 

[begreen]

No regulation change in this regard. Many overfires are user caused and not the stove design per se. There are some new designs being developed and tested that automate the air control which should help prevent this.

What stove is the with? Describe the flue system from stove top to chimney cap?

 

[Newburnerwisconsin]

Background: https://www.hearth.com/talk/wiki/why-stoves-overfire-from-too-much-draft/

I'm having this problem.

Has the EPA addressed this in any way with the new 2020 standards? Is there some sort of cfm/btu/draft calculator that can be applied with some intelligence instead of blindly following EPA or simply throwing in a key damper?

EPA 2020 has been tabled until 2023 I believe. Manufacturers in Minnesota have been fighting the new and uneeded regulations.

 

[SuperJ]

There are other jurisdictions moving forward though with 2020 style regs, (Montreal for example).
The new limits are very achievable with modern designs, so it shouldn't really be a big deal either way.

 

[bholler]

This problem is not a problem.with the regulations. It is a problem.with stove design and installaion. Modern stoves can work just fine on tall chimneys in my old house i had a 35 foot chimney and i never had an over fire because i set my system up to deal with the excessive draft i had.

I agree stove manufacturers need to give us as installers a way to adjust the intake to account for draft. But the epa has nothing to do with that. Overall stoves have improved dramatically since the epa rags were enacted. Yes there are a few issues but i for one would never go back.

 

[sadpanda]

BK Princess insert, 20 ft of single wall flex liner with insulation. Masonry chimney on outside of house.

I ran this setup for 2 years and blew out a cat despite always keeping the stove turned down because I felt like it always wanted to run away. After the cat blew out I tested draft and found 0.2-.3" on a 40F day.... So ya, lots of draft. I installed a key damper and if slam it shut then barely crack it I was able to maintain 0.08" or so and the stove seemed more stable but I feel like creosote buildup increased.

The issue now is I'm completing a gut job remodel that has required the chimney be extended by 4-5ft AND the once exterior masonry is all going to be inside the building envelope (big addition on that side of the house).... All things that will likely increase draft. I have to buy a new liner and it has to be insulated for zero clearance etc but I was considering stepping down to 5.5" dia. just to help offset.

I'm open to other suggestions.

I'm also worried I may have to fabricate some sort of outside air kit for this thing... Going from a very leaky house to a very tight house with ERV system. If I go that route and make it air tight I may be able to control the draft from the inlet side of things instead.

 

[bholler]

BK Princess insert, 20 ft of single wall flex liner with insulation. Masonry chimney on outside of house.

I ran this setup for 2 years and blew out a cat despite always keeping the stove turned down because I felt like it always wanted to run away. After the cat blew out I tested draft and found 0.2-.3" on a 40F day.... So ya, lots of draft. I installed a key damper and if slam it shut then barely crack it I was able to maintain 0.08" or so and the stove seemed more stable but I feel like creosote buildup increased.

The issue now is I'm completing a gut job remodel that has required the chimney be extended by 4-5ft AND the once exterior masonry is all going to be inside the building envelope (big addition on that side of the house).... All things that will likely increase draft. I have to buy a new liner and it has to be insulated for zero clearance etc but I was considering stepping down to 5.5" dia. just to help offset.

I'm open to other suggestions.

I'm also worried I may have to fabricate some sort of outside air kit for this thing... Going from a very leaky house to a very tight house with ERV system. If I go that route and make it air tight I may be able to control the draft from the inlet side of things instead.

How did you install a key damper on your insert? I have done a few just curios how you did it.

To be honest 2 years out of a cat may be pretty normal how much do you burn?

 

[sadpanda]

I burn ALOT. Successfully made it the sole source for 2yrs before we started the remodel.

I kinda had a two birds one stone approach to the install... The BK Princess has an angled outlet collar for some reason. To facilitate pushing the insert all the way against the back wall I purchased a 45 degree welded collar adapter I found online for a different make stove, made up some attaching bolts and bolted er up. I drilled this collar for a standard key damper and welded up an O2 sensor bung while I was at it (future project). I ended up having to notch the liner adapter a bit to clear the rod for the key but all in all it was pretty straight forward and 100% reversible. If the collar/damper becomes a permanent thing I will definitely weld it up.

Flue collar was: stove parts unlimited Angled Flue Collar for Enviro 1200 & 1700 Woodstove Inserts (50-1565)

 

[bholler]

I burn ALOT. Successfully made it the sole source for 2yrs before we started the remodel.

I kinda had a two birds one stone approach to the install... The BK Princess has an angled outlet collar for some reason. To facilitate pushing the insert all the way against the back wall I purchased a 45 degree welded collar adapter I found online for a different make stove, made up some attaching bolts and bolted er up. I drilled this collar for a standard key damper and welded up an O2 sensor bung while I was at it (future project). I ended up having to notch the liner adapter a bit to clear the rod for the key but all in all it was pretty straight forward and 100% reversible. If the collar/damper becomes a permanent thing I will definitely weld it up.

Flue collar was: stove parts unlimited Angled Flue Collar for Enviro 1200 & 1700 Woodstove Inserts (50-1565)

Ok but how do you open and close the damper? Did you make a linkage to extend it through the faceplate?

 

[bholler]

I burn ALOT. Successfully made it the sole source for 2yrs before we started the remodel.

I kinda had a two birds one stone approach to the install... The BK Princess has an angled outlet collar for some reason. To facilitate pushing the insert all the way against the back wall I purchased a 45 degree welded collar adapter I found online for a different make stove, made up some attaching bolts and bolted er up. I drilled this collar for a standard key damper and welded up an O2 sensor bung while I was at it (future project). I ended up having to notch the liner adapter a bit to clear the rod for the key but all in all it was pretty straight forward and 100% reversible. If the collar/damper becomes a permanent thing I will definitely weld it up.

Flue collar was: stove parts unlimited Angled Flue Collar for Enviro 1200 & 1700 Woodstove Inserts (50-1565)

If you burn allot 2 getting 2 years out of a cat is not abnormal

 

[sadpanda]

I had some other over fire indicators as well so I ended up getting one for free. They carry 5yr warranty no? Different chemicals but the cat in my car is good for 200k miles plus, I cant imagine cave man fire would be THAT difficult to deal with.

I ran without a shroud last year but the key damper is situated so its parallel with the ground and pointed forward towards the operator.

If it stays I will simply lengthen the operating rod so it pokes through the front shroud


How did you solve your over drafting? Just a damper or did you step down liner size like I'm thinking of doing?

 

[bholler]

I had some other over fire indicators as well so I ended up getting one for free. They carry 5yr warranty no? Different chemicals but the cat in my car is good for 200k miles plus, I cant imagine cave man fire would be THAT difficult to deal with.

I ran without a shroud last year but the key damper is situated so its parallel with the ground and pointed forward towards the operator.

If it stays I will simply lengthen the operating rod so it pokes through the front shroud


How did you solve your over drafting? Just a damper or did you step down liner size like I'm thinking of doing?

A damper works best. What symptoms of overfire do you have? Because bks are not supposed to be able to overfire

 

[sadpanda]

Well... I guess I'm on my own trying a slightly smaller liner.

With that excessive of a draft the flue temps exceed safe limits long before the thermostat kicks in on anything more then 3/4. At that level the top plate warps up lifting the top grate off of the edges... Ended up with a cracked weld around the door and some interesting hazy paint to show for it.

 

[bholler]

Well... I guess I'm on my own trying a slightly smaller liner.

With that excessive of a draft the flue temps exceed safe limits long before the thermostat kicks in on anything more then 3/4. At that level the top plate warps up lifting the top grate off of the edges... Ended up with a cracked weld around the door and some interesting hazy paint to show for it.

In all honesty 20' is not that tall. Have you checked everything out about the stove? Something sounds very wrong about this situation. I have never had any excessive draft problems with a stove on a chimney under 30'. And blazeking deals with it better than most.

 

[begreen]

The cat is good for about 10,000 hrs of service. If the stove burns 24/7 from October to April that is 210 days and 5,040 hrs.

 

[bholler]

Well... I guess I'm on my own trying a slightly smaller liner.

With that excessive of a draft the flue temps exceed safe limits long before the thermostat kicks in on anything more then 3/4. At that level the top plate warps up lifting the top grate off of the edges... Ended up with a cracked weld around the door and some interesting hazy paint to show for it.

What top plate and top grate are you referring to? If a weld is cracked the stove is probably unsafe to use at this point.

 

[begreen]

Some pictures would help here.

 

[maple1]

In all honesty 20' is not that tall. Have you checked everything out about the stove? Something sounds very wrong about this situation. I have never had any excessive draft problems with a stove on a chimney under 30'. And blazeking deals with it better than most.

I was thinking that also. We are on an open hilltop and have 30' of Class A straight up through the house, with a manometer permanently hooked to it. The only time I see draft that high is with gusty wind, which I have a barometric damper for. Normally, it is around 0.1 at full burn.

 

[sadpanda]

The cat is good for about 10,000 hrs of service. If the stove burns 24/7 from October to April that is 210 days and 5,040 hrs.

got it. Might not be that out of whack then. I usually burn Nov to march.


Straight out of Blazeking Manual:

All Blaze King free standing wood appliances are designed as radiant room space heaters. They have been designed and tested to be installed in insulated habitable rooms areas of your dwelling. The appliance has not been designed to be installed in a concrete uninsulated basement or in a shop/garage environment. Such applications may cause the thermostat to be unresponsive due the constant call for heat resulting in appliance being in a constant or over fire situation. Consequential damage from this type of operation will deem the warranty null and void.

So their thermostatic spring is not some sort of magic bullet... And if you run it hard enough it will overfire.

The top plate is exactly that. The primary top plate. By grate I was referring to the louvered diffuser that sits on top of the top plate. Side fan forces air into a duct/shroud that goes around to the back of the fire box then exits at the top through a slot. Diffuser covers the high temp area above cat and finishes off the shroud slots and directs air out.

Crack is small and easily repaired.

Rest of stove is sound. Door seal, bypass seal, door glass seal, air door chain adjustment all check out ok. The only other thing I've considered is the thermostatic spring may be out of spec but that was probably verified at the factory.

 

[lsucet]

So their thermostatic spring is not some sort of magic bullet... And if you run it hard enough it will overfire.

Many here due to their location and extreme weather in their areas run their stoves hard wide open without have overfire conditions. others do it to clean creosote in the firebox, when others to see how fast a BK can go over a full load of wood. For awhile i used to burn hot due to be going to the place on weekends only and when sometimes the outside weather was OK i still run the stove hard to bring the house to temperature as quick as possible. And almost at full throttle the thermostat always control the burn at some point what i was getting was just ghost flames in there all over in the firebox.
I did this many many many times and i have the same cat the came from factory in a good working conditions. No cracks, crumble, etc. since last winter i just run them on low after the char and my cat, depending how much wood i load and how i load can go between 24 to 32 hrs in the active zone.

 

[SuperJ]

The BK thermostatic senses flue/firebox temperature more than space temp, it's been covered a bunch of times that it is basically tough to get a "properly" functioning blaze king to overfire. Personally mine throttles pretty hard if I leave it wide open without the fans going. I don't mean that you couldn't over-fire it if you tried, but if you conscience of how your doing things and your stove is in good repair it shouldn't be something you have to worry about normally.

There are some people here like @Ashful that have overspec draft. Even then over fire was not a problem, it was more things like dirtier glass, and ash getting stuck to the face of the cat.

I'm not suggesting that you weren't overfiring, but that there must be a reason for it.
Have you contacted @BKVP ?

There was one or two instances of a thermostat cover being installing with the stat wide open which somehow prevented proper thermostat action. If thermostatic somehow got thermally decoupled (is bolted on?) from the stove then perhaps it wouldn't respond. Or if a constant cold draft, or contact with cold metal/concrete on the stat housing might fool it into staying open. Do you have a good block off plate setup?

You may benefit from a damper but I doubt it will prevent overfiring your case, of if it does it's likely a bandaid rather than a true fix, I suspect another root cause other than draft.

 

[black smoke signals]

BK Princess insert, 20 ft of single wall flex liner with insulation. Masonry chimney on outside of house.

I ran this setup for 2 years and blew out a cat despite always keeping the stove turned down because I felt like it always wanted to run away. After the cat blew out I tested draft and found 0.2-.3" on a 40F day.... So ya, lots of draft. I installed a key damper and if slam it shut then barely crack it I was able to maintain 0.08" or so and the stove seemed more stable but I feel like creosote buildup increased.

The issue now is I'm completing a gut job remodel that has required the chimney be extended by 4-5ft AND the once exterior masonry is all going to be inside the building envelope (big addition on that side of the house).... All things that will likely increase draft. I have to buy a new liner and it has to be insulated for zero clearance etc but I was considering stepping down to 5.5" dia. just to help offset.

I'm open to other suggestions.

I'm also worried I may have to fabricate some sort of outside air kit for this thing... Going from a very leaky house to a very tight house with ERV system. If I go that route and make it air tight I may be able to control the draft from the inlet side of things instead.

Since when can you insulate for zero clearance on your new pipe install?

 

[bholler]

got it. Might not be that out of whack then. I usually burn Nov to march.


Straight out of Blazeking Manual:


So their thermostatic spring is not some sort of magic bullet... And if you run it hard enough it will overfire.

The top plate is exactly that. The primary top plate. By grate I was referring to the louvered diffuser that sits on top of the top plate. Side fan forces air into a duct/shroud that goes around to the back of the fire box then exits at the top through a slot. Diffuser covers the high temp area above cat and finishes off the shroud slots and directs air out.

Crack is small and easily repaired.

Rest of stove is sound. Door seal, bypass seal, door glass seal, air door chain adjustment all check out ok. The only other thing I've considered is the thermostatic spring may be out of spec but that was probably verified at the factory.

We are trying to help you figure out what is going onwith your stove. Some pictures of the setup and damage would really help with that. I dont dont blindly defend bk and really dont beleive what many say that they cant be overfired. But from your description your install does not sound extreme at all. In fact the height is pretty typical and i would have no reason to expect any stove to have issues much less a bk. I beleive there is something else going on

 

[bholler]

Since when can you insulate for zero clearance on your new pipe install?

Zero clearance to the masonry not the pipe.

 

[lsucet]

and really dont beleive what many say that they cant be overfired.

For what i understand you have one now. why don't you try it and post the results? Or you dont want to do it just for the sake of not accept it? What, you dont want to feel you are wrong?