Blaze King princess thermostat sticky, BK Princess ultra

[Highbeam]

Most of the time the stat works great and I think it is actually pretty responsive. I load the fire in a warm stove and the coals restart the fire. I set the stat and after the stove gets hot, the stat shuts the air down and the fire reduces to cruising speed. Stove temp is maintained. Life is good.

When I first got the stove I verified that the stat was manufactured properly and that it works as designed.

So what's been happening is that the stat won't close when the stove warms up and the dang thing gets hot when on a low setting. I saw 750 last night on the stove top and the stat was set at 1.75. My fix has been to turn the stat to a lower setting and then back up to 1.75 at which time the fire visibly reduces and the temps drop to the normal 1.75 cruise temp of 500 or so.

It's never gotten above 750 and I've always been able to control it but I am losing some confidence in the automation of the device to where I feel I need to babysit it.

Has this happened to anybody? It seems like something is sticking. Is there a place to lube the mechanism? Any ideas? The thing works normally most of the time. It's just not quite closing the stat on occasion.

 

[rdust]

Funny you bring this up, a couple weeks back I had mine stick on me. When I hit the "o" on normal the fire was still raging along and I thought "hmmm that's not right, the flames usually get lazy at that point". I had to turn it up then down a couple times before I heard it "click" closed. I haven't had an issue since then so I'm not sure what it was all about. I figure I'll pull the cover off after the season is done unless it acts up before then.

 

[BLAZE82]

A couple of months after i had mine it started doing the samething, what I did to get by was remove the t-stat cover and let it run that way. Earlier this year I contacted Chris with my problem and he sent me out the newer cover with the screw in it at the top of the cover to prevent the t-stat from contacting the cover. I ended up not having to use it and what i did was put the old one back on and made sure it was pushed down as far as it would go, So far so good. What I think happens is over time the lid works its way up, if you notice the screw holes in the lid are slotted. While it was off i blew the dust out which had gathered up a good bit on the t-stat. While I was in there I noticed that the T-stat it self seemed a little sticky, so what i did was put a little 3in1 oil on the shaft and it seemed to free it up. To remove the cover it takes a square bit and theres just two screws and its off. I was also told that it is sometimes possible for the rtv selant that they use to seal the cover to work its way into the path of the t-stat butterfly. I hope this helps and if theres anything else I may be of assistance with just let me know. I have had my stove for a while and I have worked through a lot of the little bugs myself. it is still the best stove I have ever owned and ran.

 

[Highbeam]

Great info blaze. I hate to do it but I may just take that cover off and have a look see. I own the square bits so it's just a matter of taking things apart. Did Chris seem to indicate that the new cover was the fix or that you might want to clean and lube plus the new cover?

We burn until mid June most years so I still have three months left. Funny thing is that I was just teaching the wife how to use the stove while I'm away next week on business and I was saying how foolproof this new BK is. Then the thing pretty much runs away on me. I have to write a procedure now which includes the "click" before you go to bed. No more auto stat for now.

The stove isn't perfect but I am still impressed.

 

[BLAZE82]

Chris didn't really say on the new cover, but I took it that way because my old cover didn't have the screw. I would say that your stove allready has the newer cover as mine was built in 2006 and I think yours is newer if I remember from some of your older post. The screw is a sheet metal screw which prevents the t-stat from being able to go completely verticle, lessoning the chance for it to hang up on the roof of the cover. As far as the lubercating goes Chris didn't tell me to do it nor did he even mention it I just thought that it should be done because the t-stat butterfly felt sticky to me when i moved it. Just to let you know I did not move the butterfly alot by hand because I didn't want to risk damaging the biometalic spring. Removing the cover and lubing the t-stat is not a hard thing to do. I don't know if you are using an oak, but if you are not, you could always just take the cover off while you are away and reinstall it when you get back, that way you don't have to worry about the stove going nuclear with your wife. The stove with the cover off runs fine. P.S. I am sorry about the spelling Iam tired lol.

 

[nate379]

I've never really used the T Stat on my stove. Build a fire and once it's going I shut it down. Other than when it's -25* it works just fine. I control the temp in the house by how much wood I put in it.
Like tonight it's about 30* out so I just threw in 3-4 splits.

 

[Todd]

Mine has been acting up as well. Seems like the stat isn't as consistant as it use to be. I use to hear that click as it closed right around 1.5 and now I have to turn it down a little more. Maybe it's time to take the cover off and take a look.

 

[mellow]

Interesting, you think heat has an effect on the bi-metallic spring?

 

[Highbeam]

Interesting, you think heat has an effect on the bi-metallic spring?

Yes, that's the whole point of the spring. If the cycles of heat and cool are causing fatigue or some damage to the spring then we have a problem.

I do have outside air so dust should be minimal. Also, My cover appears to be the new version since it has the two retaining screws plus a third screw up high on the cover that would appear to be the stop screw mentioned earlier.

Time for some exploratory surgery. Wish it didn't have to come to this.

 

[BLAZE82]

I don't think the heat effects the spring negatively, because that is how the t-stat works, by heat. What I think happens over time is the shaft that the butterfly rides on becomes dry from the heat, as if the heat over time cooks the lubercant thats on there and drys it out, causing it to become sticky, much like grease thats exposed to heat. My t-stat went back to normal functioning after I lubed it with a little 3in1 oil. Highbeam the process to do it is not that involved and can't hurt anything, if done right. The only thing i seen after doing this was an improvement. You will however have to re-seal the cover with some high temp sealant. Also when you remove or re- install the cover make sure the t-stat is set to the lowest setting, to make sure you don't place it in a bind when re-installing it.

 

[HotCoals]

I've never really used the T Stat on my stove. Build a fire and once it's going I shut it down. Other than when it's -25* it works just fine. I control the temp in the house by how much wood I put in it.
Like tonight it's about 30* out so I just threw in 3-4 splits.

I concur 100%


I had my stove so hot a few times the dang knob was hard to turn..anybody else have that?

 

[BLAZE82]

I have had mine that hot before to and the t-stat knob was hard to turn.

 

[Highbeam]

Yikes. When I peaked the stove out at 750 (stat at 1.75) the cat had a very impressive glow to it, the cat probe meter was pointing somewhere in the writing so near 6 o'clock for the clock guys. The stat knob turned just fine.

High heat does cook the wetness out of lubes. I'll try some light oil in there after manually feeling the resistance to motion. Need some pics too to make the thread complete. Not until next week though.

 

[claybe]

Hey Highbeam, I am assuming you saw the thread about the t-stats that work opposite from what they are supposed to? That is the first thing that came to mind when I read your thread. I will see if I can find it and post it back here.

 

[claybe]

Here's the link: https://www.hearth.com/talk/index.php?threads/Blaze-King-thermostat-faulty.48603/

Could be this???

 

[Highbeam]

No, I verified proper operation early on after getting the heads up here. The stat works just fine most of the time. It's just when it sticks that the stove keeps getting hotter. Good point about the possibility though. I have ruled it out.

 

[TX-L]

My neighbor called me and said her Princess got so hot one night a smoke detector starting going off at 2 AM. The cat probe dial was twisted around and the surface thermometer was beyond 900 with a wildfire raging in the box. This was all happening with the stat setting below "2". She turned it down all the way and the stove calmed down but she didn't; she was scared to leave the stove unattended.

The stat knob was stiff, resistant to turning. I took the cover off and lubed all the points where there was a wear area with gun oil, the stat knob turned MUCH easier afterwards. Also cleaned all the dust off the flapper. It seems to work fine now, no issues since then.

This is the same stove that originally came with the backwards-wound thermostat coil. And a stainless cat that plugged/wouldn't light off properly and was replaced with a ceramic. As good as it is, it has had some issues. I have not read on this forum of any of these issues with the King.

 

[claybe]

Well I guess I need to check this out. During the cold season I would only get an 8 hour to 10 hour burn and was surprised that it ate so much wood over night. Recently I have closed it down all the way and have been getting 24 hour burns. Don't know if it was sticking or not. I was keeping it on 2 to 3 dots when it was burning fast. Let us know what you find out.

 

[Highbeam]

So I got home today to a cold stove, cold house, but pretty warm outside. No reason other than the wife doesn't trust full loads. She was loading 4-5 chunks and that just doesn't last long. So I decided to take the cover off and get this settled. First photo is me digging into my kit of oddball drivers to find the square bit. These kits are like 5 bucks at HF and will save your butt every few years. Took the two srews out and tried to remove that cover. Well it was stuck on there, it would flex, and after lots of force and me almost bailing on the job I got a light and could see that some of the sealant that they use for the thermostat oozed out and was also adhering the cover to the stove. A delicate slice with a henkels steak knife from above and the cover came off. I had turned the stat to full cold so I knew that I wasn't bending the butterfly.

Inside everything was clean as a whistle. I blew it all out with compressed air and added gun oil to the moving points. I did not remove the stat to access the coil spring because that was a major job. I cleaned the mating surface of the butterfly and lubed all shafts. Then put it all back together. Since the stove was ice cold, the butterfly would click closed at position #1.

If you've never seen the intake system it is a little weird. Air comes up from the bottom on the outside of the butterfly. Then the butterfly admits air downward into the intake manifold where the air goes to the airwash tubes.

I cleaned all the ash out and started a fire with 5 splits. It's like 58 degrees outside and inside so I have the stat set at #2. It shut right off when it was supposed to. Oh and I cleaned that sticker gunk off the stat cover. The stickers bothered me since they are ugly and were peeling up so I removed them and the adhesive was not easy to remove. It's all nice and black now.

No smoking gun. I'll keep an eye on it for awhile and maybe forget.

 

[HotCoals]

If you've never seen the intake system it is a little weird. Air comes up from the bottom on the outside of the butterfly. Then the butterfly admits air downward into the intake manifold where the air goes to the airwash tubes.

Did you see the hole that is down a ways..maybe halfway down that the stove uses for air when the t stat is shut..it is diff the way the whole thing works.

 

[Highbeam]

Did you see the hole that is down a ways..maybe halfway down that the stove uses for air when the t stat is shut..it is diff the way the whole thing works.

No, I thought that the hole (visible in my pic) in the butterfly served as the minimum air admittance hole. I didn't look for another hole.

 

[HotCoals]

No, I thought that the hole (visible in my pic) in the butterfly served as the minimum air admittance hole. I didn't look for another hole.

oh..I didn't notice the hole in your flapper.
Mines not like that..solid.
Interesting.

 

[Highbeam]

The most troubling thing I found was the spot welds holding the butterfly to the shaft. THey are less than stout and if they were to fail, we would be going WIDE OPEN.

That hole in the flapper is pretty big. About the same as a dime.

 

[jeff_t]

The most troubling thing I found was the spot welds holding the butterfly to the shaft. THey are less than stout and if they were to fail, we would be going WIDE OPEN.

The way the thing is balanced, it should fall closed in the event of a failure. At least that's what I read somewhere.

 

[Highbeam]

The literature states that if the bimettalic spring were to fail that the flapper would slam shut. If the flapper falls off of that shaft it sure looks like it would fall into the intake manifold. At least on carburetors the flapper is usually attached with screws.