Improving bimetal t-stat control

I've been thinking of how to better control the burn in my DS Machine after re-loading with coal, especially at higher temperature settings. The issue I've been having is that the stove would cool a bit after reloading, and the tstat would open too far. The fire would get too hot, too quickly, and then the tstat would completely close and the chain would be dangling loose since the stove temp overshot well past the tstat setting.

When the stove is at a low burn, I have no problems. The problem occurs when I want more heat, and using bituminous only excaberates it. I decided to try a makeshift fix to start : (edit - The edge of the coal hod is keeping the flap from opening more than about 1/4")



So far, this has worked beautifully. I was even able to toss on a pile of high vol coal from Valier's. No more raging infernos!
I am thinking a permanent solution might be to build a manual damper that fits behind the air inlet flap, so the max burn rate could be set there.

I'm curious to hear others thoughts on this arrangement.

I have also been trying to think of a idiot proof way to regulate the temp spikes that happen when my wife dumps a whole bucket of coal in on a nice happy bed of glowing coke. I have wondered about some kind of air duct that has a thermo coil set up that can react to spikes in pipe temp by closing a air shutter in a duct that leads to the factory air shutter. Kind of like a choke on a engine but would close when it gets too hot.

When I tend the stove I open the ash pan door and ramp up the stove and try to get the top temp to about 500 and add maybe 10lbs of coal to one side, close the ash door and let the stove heat up till the shutter closes down then I fill it up.

carlherrnstein wrote:I have also been trying to think of a idiot proof way to regulate the temp spikes that happen when my wife dumps a whole bucket of coal in on a nice happy bed of glowing coke....

I didn't realize the VC Vigilant had a bi-metal tstat. I pulled the owners manual up online and I see that it's supposed to have a restrictor plate in place for bituminous burning. Do you have that installed on your stove?

I'm not seeing it. Just what was the makeshift fix?

lsayre wrote:I'm not seeing it. Just what was the makeshift fix?

The coal hod is blocking the air intake flap from opening more than about 1/4". Taking another look at the pic, I guess it's not that obvious

LDPosse wrote:The coal hod is blocking the air intake flap from opening more than about 1/4".

Oh ok, I couldn't tell either ... good work

LDPosse wrote:
The coal hod is blocking the air intake flap from opening more than about 1/4".

Hi LDP, would it be helpful to hang the necessary weight on the flap so it opens at the desired slow speed, but would close faster because of the weight!...my 2 c$

michaelanthony wrote: Hi LDP, would it be helpful to hang the necessary weight on the flap so it opens at the desired slow speed, but would close faster because of the weight!...my 2 c$

I didn't think about that.... it wouldn't be too hard to attach a small weight to it, to find out!