Chubby Stove temps running high

tcalo wrote: ↑

Tue. Jan. 04, 2022 8:20 pm

It has to be an air leak below the grate if you can’t get the temps down!!

I agree. If you read my previous post I quoted this.
You must have an under-fire air leak. Shouldn't matter what size or brand of coal you use those temps seem rather high.
It cant be anything else than that. He could band aide the problem with a baro, or by closing down his MPD, but the problem still remains with his under the fire air leak.

My Chubby Jr has quite an air leak around the grate shaker rod.

The Chubby will never be air tight. It is not a "blow your ass" out of the room heater. I have learned not to force its operating point. With a full load of coal, the pipe damper fully closed and the air intake open 1/4 inch, it settles into an operating temperature that varies with the outside temperature and wind (due to draft variation). Right now in single digits, the stove is at 450 F. At freezing it settles in at around 350 F. This gives a 12 hour burn without worry of losing the fire. It is a great "supplemental" heater that actually carries most of the load in my environment. Burn one ton per season, most of it in Jan-Feb..

This is how my days gone.
Coal Stoves been running hot all year, turns out there a gasket gone that you've got to pull the stove apart to get to. No heat for me tonight.

AugustaCoal wrote: ↑

Sun. Jan. 23, 2022 6:16 pm

This is how my days gone.
Coal Stoves been running hot all year, turns out there a gasket gone that you've got to pull the stove apart to get to. No heat for me tonight.

WOW !!!!!!!!
That's not good. especially with the weather that we are having

Is that the top of chubby?
3/8 gasket?

steveleslieg wrote: ↑

Mon. Jan. 24, 2022 11:41 am

Is that the top of chubby?
3/8 gasket?

Ayuh, its the top of the chubby, and by the way I measure it I'll need about 5ft of 3/8s. Going out to pick it up today.

AusgustaCoal - Wow - I looked at mine and could see the rope gasket from the side but I guess that doesn't mean its not deteriorated some. I will have to look further at this, but I hate to take it apart in the middle of winter.

A leaky top gasket shouldnt make it run hotter, unless its burning off gasses. Underfire air makes it burn hotter.

warminmn wrote: ↑

Mon. Jan. 24, 2022 6:07 pm

A leaky top gasket shouldnt make it run hotter, unless its burning off gasses. Underfire air makes it burn hotter.

Agreed!!! Any leak above the bed would lower the draft causing the fire to burn cooler. I believe your issue is at or below grate level. Do you have a manometer hooked up or know your draft reading?

I owned a Chubby for years. My guess, the nipple where the shaker rod goes into is worn. This is common on these stoves.

Here is a link to my fix. It worked great for me and I had more control of stove temps. Coal Chubby

If you plan on keeping the stove it may be worth it to tackle this issue.

tcalo wrote: ↑

Mon. Jan. 24, 2022 8:18 pm

Agreed!!! Any leak above the bed would lower the draft causing the fire to burn cooler. I believe your issue is at or below grate level. Do you have a manometer hooked up or know your draft reading?

I owned a Chubby for years. My guess, the nipple where the shaker rod goes into is worn. This is common on these stoves.

I do not use a manometer. The stove hasn't been shaking at all this year (bent grate) so I did pull the shaker rod out and completely blocked the hole. I did this in addition to the fresh gasket up top and now the stove is burning at much more proper (300f) then previously (600-700f) fully closed. The real test though for me is always hows it burning on day three, once the midnight/noon tending schedule settles in.

I was at the hardware store buying new door gasket rope and found this thread searching for the correct rope diameter to buy.

But this I think is correct:

Hounds51 wrote: ↑

Wed. Jan. 05, 2022 7:01 pm

I agree. If you read my previous post I quoted this.
You must have an under-fire air leak. Shouldn't matter what size or brand of coal you use those temps seem rather high.
It cant be anything else than that. He could band aide the problem with a baro, or by closing down his MPD, but the problem still remains with his under the fire air leak.

On my Chubby, the hole is definitely worn around the shaker handle like others wrote, AND I have rock steady consistent high draft from a single 30 ft. 6" stainless liner run that I installed so overfiring was a problem for me too

I'm running a Field Controls TV206137 with a Dwyer manometer, and I'm not necessarily recommending anyone else do this, but to get things under control I backed out the thumbscrew on the monometer and added a washer under the thumbscrew for extra weight to run even lower draft than what can normally be dialed-in. There are two things going on here, volumetric flow and pressure; to get my flow under control, I essentially have to run higher pressure (less vacuum).

It's been like that for 2-1/2 seasons now and works great through all weather conditions, no CO problems or anything like that, and I can just idle it for 12hrs. straight at 300F, but it does give lower draft than what the Chubby manual suggests.

AugustaCoal wrote: ↑

Tue. Jan. 25, 2022 4:56 pm

I do not use a manometer. The stove hasn't been shaking at all this year (bent grate) so I did pull the shaker rod out and completely blocked the hole. I did this in addition to the fresh gasket up top and now the stove is burning at much more proper (300f) then previously (600-700f) fully closed. The real test though for me is always hows it burning on day three, once the midnight/noon tending schedule settles in.

How do you clear the ash, if you don't shake it down?

I didn't read through the thread but after a few years of heating with this Chubby I'll say this: This building's heat loss is relative to the delta between the inside and outside temps. Using coal as a fuel, the Chubby heat controls (regulating combustion air and exhaust) become less responsive at the low and high end of the temp delta. At the very low end (outside air temp in the high +30s to low 40sF) I can open an upstairs window or two to lower the indoor air temp. And at the very high end (mid to high -30sF) I can put on some more clothes.

I find a bit more range in the Chubby output control at the low end by switching to wood fuel. This Chubby seals pretty tightly and with a full load of hardwood fuel like maple or oak, I can shut the controls down and it can run at low output for 6-8 hours.