Jotel 500 lack of air control

[DonEhrlich]

My brand new Jotel 500 seems to be mechanically perfect but I notice a disturbing tendency for it to fail to control temperature rise even with the air control all of the way down. This occurs only after a fire is well established with a thick bed of hot coals. I am burning 1 year old alder in fairly small splits. This evening after refueling (roughly about a quarter of a full load) and with the stovetop temperature at about 400 I shut down the air completely by pushing the control lever all of the way left. Fifteen minutes later I noticed the temperature was at 550 and climbing. The firebox was full of lazy flames. I had seen this behavior before (the stove temp rose to over 800 that time before I discovered it) so I had been half expecting it to happen again. This time I disconnected the air inlet pipe at the rear of the stove and sealed it with a sheet of aluminum foil. That effectively shut down the fire and the temperature began to fall so I know I do not have a problem with leaky gaskets. I am afraid to load the stove up full so that it will burn overnight. Again, this only occurs when a thick hot bed of coals exists. A less mature fire behaves exactly as one would expect and the air control works as advertised. The only not-quite-standard aspect of my installation is that I am using an 8 inch insulated stovepipe mated to the 5 inch outlet of the stove through an adapter. The Jotel rep and store clerk assurred me that this was OK. The stovepipe rises vertically about 12 feet.

 

[LLigetfa]

Well... I think you answered your own question. Don't load up a bunch of small splits on top of a large bed of coals.

 

[Hogwildz]

When secondary kicks in, it will raise until it levels off then usually settles back down a bit.
As far as leak checking, did you do the dollar bill test to see if the door needs adjustment?
Loading larger splits also keep it from spiking so fast. If your loading all smaller splits, any stove will spike.

 

[begreen]

The stove sounds like it's behaving correctly. On an established coal bed we are loading 6-9" splits. The little stuff we use for starting fires and stuffing between big splits to complete a loading.

 

[Summertime]

Where do you take your temp readings?

 

[Hanko]

It sounds like you have a very good draft, which is most people complain about not having enough. I load a few small splits in the morning to get her cranking, then I add large ones to help slow her down. My draft is good, but not great, but with small dry wood and a good coal bed she will haul ass

 

[ansehnlich1]

I am using an 8 inch insulated stovepipe mated to the 5 inch outlet of the stove through an adapter. The Jotel rep and store clerk assurred me that this was OK. The stovepipe rises vertically about 12 feet.

Are you certain your stove has a 5 inch outlet, or is it a 6 inch?

Also, sounds like you have an outside air kit installed, which I don't have.

What kind of thermometer are you using and where do you have it located?

I've NEVER been able to shut my air off completely and have a temperature spike like you describe, though I have an exterior masonry chimney.

Now, if I load a pile of small 2 inch pieces in my stove and let the air open it'll start to crank real good, but you describe a full bed of coals and only a couple pieces of wood? Doesn't make sense to me.

I've never had my stove over 750 degrees.

I never burned alder either, never even seen alder for that matter. Wish I had some wood that would heat like that for my stove

 

[colebrookman]

You have some great info in the above replies. There is a learning curve to every stove that we all must perform. Just stay with it and learn from those who have been there, done that. Be safe.
Ed

 

[quinn]

Sounds like your air control lever may have slipped off the damper plate. Let your fire go out and open the front door and remove the air lever/damper plate housing cover. The air control lever should move the damper plate back and forth (open and close). If the damper plate and the air lever are not connected then you will have no control over your air intake and your fires will burn wide open (if the damper plate is not covering the air intake).

 

[ansehnlich1]

Sounds like your air control lever may have slipped off the damper plate. Let your fire go out and open the front door and remove the air lever/damper plate housing cover. The air control lever should move the damper plate back and forth (open and close). If the damper plate and the air lever are not connected then you will have no control over your air intake and your fires will burn wide open (if the damper plate is not covering the air intake).

Ah, indeed, this would cause the stove to operate as described. I agree with checking the air control slide plate to ensure it is properly seated in it's track, and the air lever is where it belongs between the two "nubs" on the slide plate.

 

[DonEhrlich]

Thank you all for the education. My 12 years experience with my old VC Encore never prepared me for a spike in temperature resulting from the addition of small splits to a very hot and mature bed of coals. Live and learn. I now know that when I load the stove up for a long burn after establishing a very hot bed of coals that I should use (mostly, anyway) *large* splits to keep the surface area down to avoid excessive generation of wood gas. In answer to the questions I received: Yes, I should have said 6 inch pipe instead of 5 inches. The air control is properly connected and is working. My thermometer is a magnetic bimetal type and is resting on the center of the top of the stove (it reads a little hotter there than over in the corner of the top where Jotel recommends placing it.) Yes, I did an air leak test and the stove is tight. I have 10 acres of mature western red alder so that is what I burn. It is a medium quality wood that can burn hot but is consumed fairly rapidly (compared to fir which I also burn occassionally) and it leaves a *lot* of ash. Thanks again.

Don
Port Angeles, WA
Jotel 500

 

[kjklosek]

Also try raking the coals forward in the firebox and set the big splits in the back on the grate. Then put some smaller splits on the coals to get the fire established this will help it burn from front to back and give you some good long fires.

J.P.

 

[xman23]

I had a similar issue. When my Oslo was new, (8 years ago) the air control slide would get sticky, near the fully closed position. It would cause the slide to go past the the fully closed position. The slide lifted up and allowed air to get thru. Now I keep the slide moving smoothly by lubing once or twice a year with P&B;dry lube, get it at HD. To get to this, remove the cover held by the 2 cap bolts inside the front door. My brother in law said the front door on his new Oslo rubs on the air control lever. He said it did something like mine, but I don't think this was my problem.

I can say no matter hot or how much small wood I stuff in on top big bed of coals, I can always control it. Sometime it takes closings the air all the way off, but you know it's not going to get hotter. It does sound like you have an air leak.

Tom

 

[colebrookman]

If you had an air leak cutting off the epa air in the back would do nothing to the front air leak and would still allow the stove to burn hot. Check the front air just to be sure but I don't think it's a leak. One man's opinion.
Ed

 

[DonEhrlich]

I had a similar issue. When my Oslo was new, (8 years ago) the air control slide would get sticky, near the fully closed position. It would cause the slide to go past the the fully closed position. The slide lifted up and allowed air to get thru. Now I keep the slide moving smoothly by lubing once or twice a year with P&B;dry lube, get it at HD. To get to this, remove the cover held by the 2 cap bolts inside the front door. My brother in law said the front door on his new Oslo rubs on the air control lever. He said it did something like mine, but I don't think this was my problem.

I can say no matter hot or how much small wood I stuff in on top big bed of coals, I can always control it. Sometime it takes closings the air all the way off, but you know it's not going to get hotter. It does sound like you have an air leak.

Tom

Tomorrow I will take off that cover and inspect the degree to which the inlet air is shut off by the lever. My stove is new and the control lever is sticky near the closed position. Tom's experience suggests that the lever should be able to cut off the air completely and I have already proved that it does not by blocking the external air inlet and observing that the stove does then shut down. So, I know the gaskets are all tight and that residual air is getting in through the primary control valve. I had been assuming that the Oslo was designed to let a little residual air in but maybe that is not the case.

I will remember the suggestion to place big splits to the rear after raking coals to the front and try it that way when it next gets cold enough to try for an all night burn.

Thanks again,

Don

 

[begreen]

The air is not cut off completely on EPA stoves. This is by design. Your assumption that there will always be some residual (secondary) air supply is correct. This is how clean burning is assured.

Alder burns up quickly. Stick to larger splits. And watch, by this weekend, when it appears that winter will be arriving in force, you will be happy your stove is getting hot. Try to keep it under 800 and adjust the split size. The stove sounds ok. If the air control gets sticky, tell the dealer that you are experiencing air control lever sticking and need Jotul's modified air control arm.

 

[xman23]

Tomorrow I will take off that cover and inspect the degree to which the inlet air is shut off by the lever. My stove is new and the control lever is sticky near the closed position. Tom’s experience suggests that the lever should be able to cut off the air completely and I have already proved that it does not by blocking the external air inlet and observing that the stove does then shut down. So, I know the gaskets are all tight and that residual air is getting in through the primary control valve. I had been assuming that the Oslo was designed to let a little residual air in but maybe that is not the case.

I will remember the suggestion to place big splits to the rear after raking coals to the front and try it that way when it next gets cold enough to try for an all night burn.

Thanks again,

Don


Don ,
I've read that the air control on many stoves doesn't let close you off the air, but from what I can see, the slide in the Oslo does close the air completely. Unless there's a hidden path in I can't see. What's the air inlet pipe you disconnected, is it an outside air to the secondary burn tubes at the bottom, back of the stove. Could this be an issue? Mine is open to the room. I didn't think you could supply outside air to the Oslo.

As BeGreen says these stoves have the secondary air supply to the top of the stoves burn tubes, there's no control of this air, but somehow I don't think this feeds the wood with air to burn, just the exhaust gasses, so I think. Maybe some here can explain how this works.

When the my stove is cranking 500 - 800, I can slow burn a complete full load with the lever barely moved off the fully closed position. With the same fire if my wife ( full on / full off, Sue) closes it completely we can put the flames out pretty quickly.

I think my wife's brother bent the lever to fix the problem he had with it rubbing on the door. My sticky slide had something to do with opening the front to clean the glass and the ash going everywhere. Although I never found it was getting into the slide, I no longer open the front, and keep it lubed it now works well.

Tom

 

[jtdiesel65]

I'll add my two cents since I dealt with problems on my olso.

I had an air leak such that I could not control the stove temp. I've fixed it somewhat, but it still exists. It's almost as good as new, but not quite. I've come to the conclusion that the stove needs to be rebuilt since the airleak is near the air control slider....you would have to separate the inner front wall from the outer front wall to fix it which means almost completely disassemble the stove and so that is a project for next summer.

As mentioned previously, the slider can ride up creating a gap for air. I found that this is most likely to happen if you slam the slider over to "off" with force...like with your foot. On mine, you can gently slide it over to shut off and then if you strong arm it, it will move a bit more and ride up. So all you need to do is gently slide it over.

If your stove appears to be out of control in terms of temp and you're worried about it, simply cut a ~5x8 piece of paper and stick it on the intake hole on the bottom back of the stove. It's not hot enough there to catch fire. My experience is that it's never even really that hot to the touch. Keep in mind, the paper will fall off if you open a door and change the source of air. This summer during my rebuild I will be installing a short ~5" length of pipe and one of those "in-pipe" dampers as a secondary means of control. If I had outside air unit, I would use one of those dampers too.

Even if you cover the intake hole, air still is not completely shut off. Air will enter the unit around the hinge for the air control. This isn't really significant.

My take on it is if your stove is new and your temp is running up with the air shutoff, then the air bars are feeding the fire. The only way to stop that is to seal off the intake at the rear.

 

[jtdiesel65]

"That effectively shut down the fire and the temperature began to fall so I know I do not have a problem with leaky gaskets."

I forgot to mention one point. The stove has two layers of walls in the front and back. So covering the intake hole only proves that you have no leaks in exterior joints and gaskets. You still might have a leak along one of the interior walls from the exterior/interior wall sandwich space into the firebox. In my investigation, I found leaks around the seams that were visible once I removed the access cover.

 

[BrotherBart]

Also take a look at post number five on this thread for a way of burning the load without the heat spike.

https://www.hearth.com/talk/threads/32314/

 

[DonEhrlich]

Thank you. That description is very helpful. Also, thanks to all who responded to my question. I have now learned that my Jotul is working as it should and that my concern about not being able to control the burn was caused by the secondary tubes burning after loading a big load of small splits over a wide bed of very hot coals. As has so often been said here... every stove requires careful observation and practice to learn how to operate it (and a forum like this one, I might add).

Don