Hearthstone Heritage, I think I might be starving...........

[dkuntz413]

I have been using my new hearthstone Heritage for almost two months, and have been watching its heat output gradually diminish. My Chimney and cap are fine. My wood is fine. The stove is running now, and if it wasn't I would open the ash pan door and take a look inside, which is something I've never done as I just shovel the ashes out. If the door is open a crack to allow air in, the stove roars. As soon as the door is closed, the stove calms right down and has a hard time pushing past 300 on the stack. So, does anybody here have an idea why I'm not getting the air that I used to? Could it be ashes blocking my air flow that I can't see? Could there be an obstruction up front where the air comes in through the small round hole? The air control lever disengaged or somehow not opening all the way. I will definitely have a look inside the ash pan door next, but was hoping someone could help me with this before we hit the single numbers on Thursday. This has to be an air flow problem.
Thanks
Doug

 

[edthedawg]

This may or may not be a silly question, but do you have an OAK (Outside Air Kit) installed?

And when you say "If the door is open a crack to allow air in, the stove roars." - do you mean the ash pan door? or the side loading door? Or (I can't imagine...) the front glass door?

And when you say "the stove calms right down and has a hard time pushing past 300 on the stack" - you're talking surface metal temp of the flue pipe?

As for the primary outlet hole inside the stove, my experience is that if you can see it, it's very likely clean. I rake my coals in front of it at every reload, but the last thing i do is ALWAYS to create a little dugout valley right around the hole, and it's extremely noticeable once I close the side loading door that air is rushing very strongly in thru the primary hole. That little hole (as Highbeam once promised) is an awesome little jigger to restart a fire, even when you're down to just a few coals...

If you're not seeing your fire respond to moving the primary control lever, but cracking the door makes it run like wild, then yes - strongly suspect a blockage in the primary air feed.

 

[dkuntz413]

Never had the outside air kit, and the stove was fine earlier
Its the side door open that gets the fire going
I am talkig 300 on the surface metal of the flu pipe
I can see the primary outlet hole and you can tell air is moving from it but I suspect not as much as before
When you say primary air feed do you mean intake that is at the back of the stove? I don't really know what could get in there to block it.
Thanks for your reply.
Doug

 

[Todd]

Hows your wood supply as far as dryness goes? Also check your main air supply lever to make sure something didn't come loose and is possibly blocking the slide.

 

[edthedawg]

On a cold stove, take a little stick and gently try probing the "hole" inside the stove - don't risk snapping it off in there or packing / wedging something in there - just look for free movement inside that casting.

Then look for the lever underneath - you still hear the metallic chain-like rattle from moving the primary lever? or does it feel like it's changed its noise or resistance?

And one final thought - since you don't have an OAK - do you have dogs or cats? other animals? That air intake in back there is sucking massive volumes of air in, all the time the stove is running. it'll become a collector of anything it can find - pet hair included. perhaps you could try shopvac'ing it out? Just a thought... At very least, peer back there w/ a flashlight and a mirror...

300F flue metal surface temp ~= 600F flue gas temp, which is right where you should cruise, but for fire-up you need to be able to get higher, then back it down. If you can't get over 600 flue temp then yeah - you have a blockage somewhere.

I'm very interested in where this winds up - please keep the followups coming as you dig in deeper!

 

[mikeathens]

When I bought my heritage, the dealer did say that smetimes the air control lever can come loose...he said he had one returned for that reason. He would lay the stove on its back to fix it. Maybe you have a mirror that you can slide under there and check.

On my Mansfield, I actually found a bunch of dead wasps in my primary air intake...when I cleaned them out, the stove *seemed* to work much better (could be my imagination, of course).

Definitely keep ashes from in front of the doghouse. I suppose it's entirely possible that you got some charcoal or ash crammed up in there.

Other than that, all I can say is good luck.

 

[Zulu45]

While I am not sure that the primary air jet is the source of your low heat output, I did have a similar issue recently with low air supply from the "primary air jet" in my Hearthstone Heritage (purchased/installed November 08). At first, I thought the low flow was the result of an ash/crap obstruction in the air delivery manifold. However, on closer inspection, the rectangular riser/manifold joint at the back of the firebox where air is heated and supplied to the secondary air tubes had "failed" and was allowing air to be drawn into the back of the firebox. When allowed to cool, I could easily move the rectangular riser/manifold by hand . While I don't know the authorized fix from the factory, I cleaned and sealed the joint with some Rutland black hi-temp stove gasket cement (the silicate stuff, not the RTV). My primary "jet" intake into the stove is now much improved and, if i remember correctly, very similar to the performance when the stove was new.

On a separate issue....my newly installed Condar probe thermometer is telling me that the flue exhaust gases run from 1200-1350°F when ever i run the Heritage at 1/2 throttle or more....think it must be crap...is 1350°F even possible when burning wood? I have a second thermometer on the way to compare!

 

[Highbeam]

Wow Zulu, that meter is wrong or you must be burning acetylene. I too had to seal up the top and bottom of the rectangular steel tube with rutland black. I didn't want ash falling into the stove's bowels and didn't like the air leak at the top. I also ran a bead along the interface of the iron manifold and the back stove wall. I actually had removed my entire secondary manifold and the factory cement so I wanted to put it back tightly.

Doug: Since you only report pipe temp I can't tell if the stove is fully warmed up when you are trying to get a raging fire. An open door can let far more air into the stove than a fully open primary so I am not shocked to see that the stove is flared up when you open the door. This is the point in leaving the door cracked during initial startup until primary air is enough to carry the fire. Maybe you are trying to load the big wood too early.

At this point I will assume a 400 degree stove and am guessing your problem is caused by either fresh wood that is not yet hot enough to burn violently on stove air alone, or wet wood that hasn't dried out sufficiently to burn violently on stove air alone. In my stove, patience, dryier wood, and smaller splits will solve both of these.

So to be sure, you are trying to give full air with the lever full left right? And when you close the air by swinging the lever full right it is effective at snuffing the fire? Meaning, is the air control working? We need stove top temps to know what is going on.

Oh and you can open the ash pan door anytime. It won't hurt a thing. You can even put a pizza in there or bake a potatoe.

 

[Zulu45]

Highbeam, thanks for the post. For the record, I have enjoyed and learned quite a bit from your previous posts. Thanks!..... However, I am a little curious why you were compelled to seal the ~6" interface where the soapstone meets the "side length" of the cast iron riser? Additional stability? ...Just want to make sure I understand....the Hearthstone manual I have is not very helpfull

 

[jeffman3]

Highbeam, thanks for the post. For the record, I have enjoyed and learned quite a bit from your previous posts. Thanks!..... However, I am a little curious why you were compelled to seal the ~6" interface where the soapstone meets the "side length" of the cast iron riser? Additional stability? ...Just want to make sure I understand....the Hearthstone manual I have is not very helpfull

I have found that the Hearthstone manuals are of little help in regards to protecting your stove from damage. I trust the expertise and experience of the members here, more then the manual, at this point.

 

[edthedawg]

Zulu - you have 40' of lined, interior chimney? Do you have a flue damper on that thing?? You need one!

Zulu & Highbeam - I would enjoy seeing a pic or sketch or something of these "repairs" you both seem to have done - I'm not experiencing any symptom but I'd seeing what you found & fixed.

Highbeam - "you can open the ash pan door anytime. It won’t hurt a thing." If it's a solid ash bed, you can - then there's no way for air to flow up there. If no solid ash bed, opening the ash pan door, esp w/ the pan empty, will make the fire flare MASSIVELY. This is a classic recipe for overfire - and the manual is accurate in this instance... (and if you're baking pizzas or potatos in there, you must like the taste of ash, or be an ardent follower of the book "Manifold Destiny")

Doug - HB asked a few questions about the wood, and I have to wonder as well - are you getting any trademark wet-wood hissing or bubbles? Have you changed anything else w/ your loading? We've recommended a lot of other things too - just curious if you've noted anything interesting...

This morning it was dang freakin cold - I shoulda gotten up in the middle of the night to reload, because my 10pm load was nice and hot (450+ stovetop) at 11:30, but dead and gone at 6am. Oil/steam heat was whistling like mad when i finally got up. I scrounged up a handful of coals (literally - a pile about 4" square w/ faint glow), piled those directly in front of the primary "hole" w/ a wad of shredded cardboard and a couple sticks of lath kindling directly on top, w/ small splits above and behind, and a big split in back (plus of course an Eco log bedded in the middle of it all). Shut the door, had to wait 20 seconds this time - but *poof* - no matches, no bellows - just plain fire in the hole. After an hour it wasn't down to much in the way of coals, but we had to leave so i plunked two big splits and another Eco log on top of it all for the day. after 20m, closed the damper and the primary and it'll just sit there keeping the place warm all day, despite a present high of 17F and falling thru the day...

 

[dkuntz413]

I have the pipe disconnected from the stove,stove pulled away to inspect the air intake which looks fine. primary hole feels good with a lobster picking tool in there(no Lobsters though). Chimney and cap are clean. Some of my wood hisses a bit but only 10 per cent of the time. I don't think it would hurt to put the shop vac over the primary hole and see if that does anything.I know this is a fussy stove when it comes to seasoned wood and getting it up to temp. Its the getting it up to temp that seems to not be what it once was BUT last night after burning for a little over a couple of hours with a nice 3 inch bed of hot coals, after adding 3 med size splits, it seemed to want to climb in temp better. Of course it was midnight, and I needed to get up at 4, so I closed it down, and went to bed. There were still enough coals to get another fire going, but I let it go out to clean it and pull it away from the wall to inspect the air intake.Perhaps, and this a big perhaps, but possible, this stove will not work its best until it has run long enough for a good bed of coals to be there and enough wood added to it to get it going but not smother it. It just seemed to come up to temp much faster when I first hooked it up. I have at least discounted a few things by inspecting the air intake in back. I might need to just be more patient with it until it gets going more. Thanks for all the replies to this.
Doug

 

[edthedawg]

It is a little finicky - esp coming from cold and trying to heat up fast. It just don't do that. Mine loves to get hot and stay hot, but the "get hot" part is not something that happens quick at all...

Just another crazy thought / data point, but what are your ash removal practices? It's another finicky point, but there is a "magic carpet" level of about 1" to 1.5" of ash - anything outside that tends to really impact things. I scoop ashes about every 2 weeks to maintain that level (i'm about due right now). If you're scooping ashes every day, that will greatly affect performance. Same if you're letting the bed grow higher than the hole - it might look accessible, but it'll kill the flow.

Didja look up from underneath and see anything odd or otherwise? Were you able to see anything happening inside the rear intake while moving the primary lever?

 

[dkuntz413]

nothing odd underneath
rear air intake is connected to the flap that opens and closes but cant see the flap it does sound and feel as it always did. I think that I have been cleaning ashes every 3 to 4 days by shoveling pretty clean. I have not let this stove run for more than 2 days continuous for a few weeks as I have not been around the house a lot
Now that I have looked at everything, I'm going to put it back, light it and see how it goes after 3 or 4 hours, and keep it going as its in the teens today for a high and heading for the single digits tomorrow. My ash scooping will be cut back from now on. Thanks
Doug

 

[edthedawg]

I could definitely see frequent start/stops, and scooping ALL the ashes out every 3 or 4 days contributing to poor performance... let 'er run... and run... and run... then you'll have a better basis for your performance assessment.

good luck!

 

[Highbeam]

In checking the air control lever it is pretty tough to see anything on this stove. The linkage is all buried inside the bottom casting so the best you can do from the front is to listen really good to the stove as you slide the control to hear the innards move the whole time. In Doug's case it sounds like the stove and chimney are fine. I highly suspect weather changes and wood changes to be responsible for the change in performance.

When it gets really cold we tend to load bigger wood for longer burns and also we become much more critical of the heat output since the house walls are sucking heat from our backsides much more quickly. These stoves have a narrow operating range as far as temps so when we are confident and able to keep the stove at 450 during 30 degree weather all is warm and life is good, but when it is 2 degrees outside we can only really increase the temperature by 100 degrees and that may not be enough to overcome the losses to the outside.

Doug, try this, split the wood smaller. Down to 3-4 inch splits and load up the stove like normal. These splits will be consumed more quickly than the larger ones but heat up the stove sooner. Then when the stove is up to running temp you can increase the split size but not too big. There's just not a lot that can go wrong in our stoves, not many moving parts.

Zulu, I had the whole secondary system out of the stove at one point and cleaned all the cement out trying to provide clearance to seat the secondary manifold all the way down. After reassembly I actually witnessed the air fanning the fire from that top connection of the steel riser tube so I wanted to seal that up. Well the steel tube is a loose fit between the bottom of the secondary manifold and in the stove base since the secondary manifold is held up by that single screw in the stove back. You also can't seal these connections on the back of the riser (top and bottom) since it is against the stove's backwall. Hearthstone cemented the riser tube to the backwall "liquid nails style" so I didn't feel bad about trying to replicate this. I actually went in there and ran a bead along the top and bottom interface of the riser tube to the castings, between the riser tube and the back wall. And finally, to stabilize the secondary manifold which is a 3-legged horse, I actually ran a bead along the horizontal length of the bottom of the secondary manifold along the wall. Rutland black is cheap, that little tub goes a long ways and I don't expect to ever remove the secondary system again. Hearthstone had tons and tons of the cement oozing everywhere.

There was one guy on this site that actually stucco'd the whole inside of the stove with a grey cement. The inside corners were rounded and the riser tube was pretty buried. He layed it on like refractory lining. Not sure how it looked after the first fire though. I wouldn't go that far but I am not afraid to be liberal with the stuff.

I'm pretty sure that the ash system is made to be operated with a fire going so the short term effects of opening the ash door are not going to damage the stove. I wouldn't just leave it open though. Good point about ash droppings, I wouldn't want it on the pizza. Wrap your food in foil. Whenever I've opened that door I've only had a slight dust of ash in there. Yes, a bed of ashes in the firebox really improves the stove performance for me too.

 

[dkuntz413]

Thanks to everyone who replied to this.
After pulling the stove out to see all that could be seen, everything seemed to be in order. I did put the shop vac on the primary air hole, and am not sure what came out of there.
It does seem to be moving more air. The center of the log in front of burns down more quickly, and you can hear the air again when the stove runs wide open.
Perhaps just as important, I'm using smaller wood, which is making a big difference. After two months of using this stove, I started acting like it was the Defiant that ate anything you could throw at it. I had this stove for 8 years. The Heritage, is to say the least a bit more temperamental.
Thanks again.
Doug

 

[Highbeam]

I hate to say it but....

You've got to heat the girl up before putting in the full sized wood.

I know, I know, I couldn't help it.

A nice bed of coals and a stove at full temperature will allow ignition and combustion of the larger pieces and those larger splits are usually enough to maintain the stove at the higher temperature.

 

[edthedawg]

You've got to heat the girl up before putting in the full sized wood.

You HAD to go there... sweet! :coolgrin:

in all seriousness, with these frigid temps, i'm loading earlier in the cycle. even with marginal seasoning, throwing a pair of good large splits on the hottest coal bed is a sure sight more favorable than trying to get those same splits to flame up cold...

so one might say... it's not only heating up the girl... but also the way you make the bed.