Thermo Control boiler gasification?

[Bruce2500]

I have the original limiter with the added washers underneath. I have a laser heat gun and the cutout temp on the stovepipe surface under the disk is around 420. If the temp would stay there I'd be fine but that's my problem, the disk opens up at 420 and resets at about 170(it takes that long). If I set more space and had the disk opening at 500 or whatever, once the damper opened the stove would climb there and shut down and cycle, regardless of the boiler water temp. I jumped the switch out once and monitored the temp, it climbed to 700 no problem, probably would've gone more had I not stopped it???? My aguastat also is adjustable, I keep it at 180. I set the oil burner to 145 when running the wood boiler. Thanks for the response.

 

[Standingdead]

Ah, I see it's the the length of time the switch shuts off the air flow is too long. I am curious what size splits you burning. As I mentioned I tend to burn small loads and fill often. My split sizes are relatively big say 24" long by 5 inch diameter. I found those bigger splits burn a little slower(cooler) and don't trip the switch. 3-4 make a nice 350-400 stack temp fire at its peak. Maybe they make stack switches with upper and lower limits? 250-450 would work nice for these stoves IMO.

 

[Bruce2500]

My wood is split 24 long X 8(average). 5 would be small in my pile. I do tend to load up the stove to try to minimize load times, mostly out of necessity. Maybe a switch that shuts down at 600, but I don't understand why the company put such a low one with the stove in the first place. Calling back to the company numerous times gets me nowhere, they don't want to hear anything negative and any problems are created entirely by operator error. BTW, along with spacers under the disk I have also moved the disk away from the stove closer to the chimney inlet.

 

[Standingdead]

I agree about the original switch being too low. Never called the company though. I figured i needed a different switch because my 35 foot chimney created a stronger draft than most. My liner stays pretty clean, I clean it twice a season. Sorry I can't remember the website I got the switch from. Let us know if and where you find a better switch. Thanks.

 

[rwh442]

Bruce,

The damper actuator I added to control my stack temps to 600 deg F controls the air flow into the bottom of the door intake box. It regulates the air flow by rotating a plate across that bottom opening. I capped off the top opening of the door intake box completely. The OEM damper motor is still in use - I have it shut closed when either the water temps get to 185, the stack limit switch activates (mine seems to go off at around 650 or so while at that temp or above for a while), or when my PID stack temp controller sees a temp above 700 at which I am "out of control" and then open it back up around 550 . I never really see my stack limit switch activate - my stack temps don't get there and stay there for long enough for it to trip. I just left it in the circuit as another safety device. Is your air gap between the switch and stack set correctly?

 

[Bruce2500]

rwh222,
You must have the linkage going through the door via a hole you drilled that turns your plate to open/shut air coming from the original damper opening outside the door? If I'm following you then this plate is roughly 13" x 1-1/2". My stove came with the top door intake sealed and only takes air from the bottom. I would be curious to see the inside setup if possible. As far as the air gap being set correctly, probably not. I have added about 1/4" of spacers underneath and moved it close to my chimney inlet to get it so it kills the system about 450. Even there it is still the controlling factor of my burn. I need to do something similar to you.

 

[rwh442]

Bruce,

The damper actuator I added is bolted to the bottom of the door intake box and hangs out in front of it and the door. I just made a bracket for it out of sheet metal. You should be able to see that in the pictures I posted in reply #13 in this thread. If you need to ask further questions maybe send me a private message or "conversation" I think it is called in this forum and we can get in touch that way or even over the phone.

 

[Boiler Installer]

Hi Bruce,

I am familiar with that stack limit switch and all you have to do is first of all put a thermostat on your black pipe about 18 inchs above the outlet of the stove. Get the stove burning and watch the temp on the stack. The temp should rise to about 400 or so maybe 450. If it not reaching those temps, all you have to do is adjust it away from the pipe with a washer under each screw. Each washer will raise the stack temp. about 75 or 100 deg. The more washers, the hotter the burn. This will fix your problem and it is the exact way you are advised to adjust the stack limit switch in the owners manual. You are not tricking anything. If the stack limit switch was mounted farther away from the top of the stove you would also get a hotter burn. Who installed the stove?

Happy burning

 

[mikjmartino]

Hello, I am new to these forums but reading through the strings it seems there are ideas here that will help with my dilemma. I have used a Thermo-Control 2500 for 5 seasons skeptically going into the 6th. My stove appears to be what they offer as the 2000 today. My problems is that the high stack temp limit switch is what shuts the front damper down 90-95% of the time, resulting in the high temp limit ultimately controlling my boiler water temperature, not a good scenerio. I see the aguastat controlling the damper maybe 4-5 times a heating season. So I get a problem with the boiler keeping up with my heat demand because it's out on high limit which is a timed reset and vicious cycle. Damper reopens, air races through heats pipe and trips on high heat again. While the damper is forced closed the smouldering fire is now sooting up the chimney. Not uncommon for me to go on the roof and clean the chimney every Saturday morning. I am interested in what rwh442 did with the damper control. You must have set that up to modulate and seek a position that will keep the temp around 600 degrees. How is your linkage set up to accomplish this and also shut it completely down should you get a high temp situation? Any ideas would be greatly appreciated as I just can't see what I'm doing wrong.

Hi Bruce. Put a washer between the pipe and the stack limit switch to space it out. That was the suggestion from the tech at Thermo Control. It worked for me and allows high temps. I think someone else had that idea too. It is easier and cheaper than replacing the switch.