Thermostat malfunction?

[DWIGHTTBP]

Hi- I think could use some help with the thermostat on our ~10 yr old Blaze King Princess. I've noticed it's not damping down the fire nearly as much as it used to. Today I gradually closed it down to about the 1.5 position (to the "o" in normal) after closing the bypass and letting the fire get well established as I normally do. After about an hour it was still burning hot - I could still see active flame burning in the fire box. I turned the thermostat down to the 1 position and after more than 15 min it's still burning with visible flame. See video here: https://photos.app.goo.gl/cNWN45UCrKAWx6cY6

After 45 min damped down to the 1 position there's still a red glow in the fire box.

It never used to do this and the stove is otherwise working flawlessly with a brand new combustor installed a month or so ago. And the seal around the door is tight, the gasket having been replaced in the recent past.

Can anyone suggest how to inspect the thermostat to see if anything needs to be cleaned or replaced? The operating manual says to consult a Blaze King dealer but surely there's a way for users to check the thermostat for problems?

Or maybe something else is going on and I'm just not thinking straight?

Thanks for any help you can offer!

 

[TheElementalCashew]

Can you still hear the flap clank shut when turning from wide open to the usual closed position?
You might check the window gasket as well. Hold each side of the glass and see if it wiggles at all. You may also check the door gasket again with the “dollar bill test.”

 

[Highbeam]

The thermostat flapper is easily accessible on the rear of the stove. I have cleaned mine and lubricated the axle since I too felt like the thermostat was not closing as early as it should. No harm done if it didn’t need the maintenance.

 

[DWIGHTTBP]

Thanks Highbeam and TECashew! This is embarrassing but even though I checked not too long ago, TECashew's comments inspired me to take another look at the door seal (dollar bill test) and it did, in fact, need to be tighter. So I adjusted the bolt which tightened up the door seal and of course solved the problem. Duh. Sorry I didn't check before asking for help! HOWEVER, I'm intrigued by TECashew mentioning being able to hear the thermostat make a sound when turning it down from wide open to the normal range. I've never heard our stove's thermostat make that noise. I've read other forum contributors talk about hearing that sound which has always confused me since I've never heard it. So both TECashew's and Highbeam's comments make me want to go ahead and check out the thermostat. Is it as simple as unscrewing the square screws on the back of the stove? Even though the label says not to open the cover?

BTW - happy new year...

 

[TheElementalCashew]

Thanks Highbeam and TECashew! This is embarrassing but even though I checked not too long ago, TECashew's comments inspired me to take another look at the door seal (dollar bill test) and it did, in fact, need to be tighter. So I adjusted the bolt which tightened up the door seal and of course solved the problem. Duh. Sorry I didn't check before asking for help! HOWEVER, I'm intrigued by TECashew mentioning being able to hear the thermostat make a sound when turning it down from wide open to the normal range. I've never heard our stove's thermostat make that noise. I've read other forum contributors talk about hearing that sound which has always confused me since I've never heard it. So both TECashew's and Highbeam's comments make me want to go ahead and check out the thermostat. Is it as simple as unscrewing the square screws on the back of the stove? Even though the label says not to open the cover?

BTW - happy new year...

Yep, just those two screws and wiggle the cover off. Just be sure that before you put the cover back on, the flapper MUST be turned to the closed position.

Happy New Year!

 

[Highbeam]

The two black screws. There will be some black sealant that sticks it on the first time but that sealant just oozed out from a close by seal and does not need to be reapplied.

Clean the dust and inspect the motion of the flapper. You want the flapper to easily move with very little effort and easily bounce back to the same position. No stickiness in the axle. I used spray silicone lube on the joint but some folks use dry powder lubricant.

While the cover is off you can lubricate the thermostat rod tension washer too. It’s right on the rod inboard of the knob. Will really smooth out the knob turning.

Those warning stickers have all fallen off of my princess.

 

[DWIGHTTBP]

Thanks TEC and Highbeam! Waiting for some warm weather so I can let the stove cool enough to get into the thermostat....

 

[Highbeam]

Thanks TEC and Highbeam! Waiting for some warm weather so I can let the stove cool enough to get into the thermostat....

It’s super easy. I might take a peak at mine too and spritz some lube in there where it counts. Let us know how it goes.

 

[DWIGHTTBP]

Just inspected the thermostat and everything looked super clean! I lubricated key points w/spray silicone, made sure everything's moving smoothly and closed it back up making sure the flapper was in the closed position. I really appreciate your help! I have a much better idea of what's going on with the wood stove. This forum is super helpful, thanks to folks like you guys!