Temp swings BK King

[Bill in the U.P.]

Hello all. This is our 4th year running our BK King. Everything seems to be operating like previous years except for very micro adjustments on the thermostat will cause a big temp swing. This morning after the stove was cruising I turned the thermostat down the slightest amount. An hour later it was in the active zone but just above the line. I turned the thermostat ever so slightly (maybe the tip of the arrow moved 1/16th of an inch) and maybe an hour later it was burning beyond the white zone on the cat gauge. Is this and indicator we need a new cat or is this indicative of some other problem?

 

[begreen]

The shaft may need lubricating. Take the cover off and spray with silicone. See if that helps.

 

[reaperman1]

Thats how mine runs too. On my stove I can see the flapper as I adjust the dial. I swear the flapper barley moves but makes a big difference in temps.

 

[Bill in the U.P.]

Thats how mine runs too. On my stove I can see the flapper as I adjust the dial. I swear the flapper barley moves but makes a big difference in temps.

It seems to me something has to be different. I will try lubricating per begreen's suggestion too.

 

[moresnow]

Next time you do your turn down let the gauge do the dive as described.
Instead of turning it back up just leave it and walk away. Come back 40-60 minutes later and check the gauge. Report what happens.

 

[Highbeam]

Hello all. This is our 4th year running our BK King. Everything seems to be operating like previous years except for very micro adjustments on the thermostat will cause a big temp swing. This morning after the stove was cruising I turned the thermostat down the slightest amount. An hour later it was in the active zone but just above the line. I turned the thermostat ever so slightly (maybe the tip of the arrow moved 1/16th of an inch) and maybe an hour later it was burning beyond the white zone on the cat gauge. Is this and indicator we need a new cat or is this indicative of some other problem?

This is how a BK works on low. When the fire is barely burning but making lots of smoke the cat has to eat all that raw smoke so it gets really hot. If you were at a higher thermostat setting, the cat would likely cool down because more of the combustion would be occuring on the actual wood, aka primary combustion.

Running the thermostat so the bat gauge is barely in the active zone means you are on the ragged edge of cat stall and likely making a mess of your flue.

You shouldn't be driving your stove by the cat gauge other than to keep it from going out.

Also, yes, the stove is quite sensitive to small knob adjustments. I wish the dial was larger with better marks like a woodstock.

 

[stoveliker]

I agree with highbeam and moresnow.
In my situation, if I see what is described, I have dialed it down *too fast*.
(I have not stalled it yet, even burning 36.5 ish hours at 42 F or so - possibly due to good draft from a tall flue, and due to the fact that I cross over to heat pump at warmer temps.)

What I do in such cases, i.e. if I dial down when the gauge is "mid range" and the gauge subsequently decreases to barely into the active range (and smoke comes out of the chimney), is that I notch the thermostat up by about "an hour" on the dial.
This gets the cat gauge go to mid range or higher, and then I dial down to the same as before, but slower. That has always resulted in a nicely glowing cat, no smoke, and long and stable *heat outputs* (even if the cat temp cycles up and down a bit - it never goes back to smoking and just in the active range - and I don't care as long as it's active).

And the second thing I do is remember (again...) to dial down the stove slow enough for it to be able to follow my lead.

 

[BKVP]

This is how a BK works on low. When the fire is barely burning but making lots of smoke the cat has to eat all that raw smoke so it gets really hot. If you were at a higher thermostat setting, the cat would likely cool down because more of the combustion would be occuring on the actual wood, aka primary combustion.

Running the thermostat so the bat gauge is barely in the active zone means you are on the ragged edge of cat stall and likely making a mess of your flue.

You shouldn't be driving your stove by the cat gauge other than to keep it from going out.

Also, yes, the stove is quite sensitive to small knob adjustments. I wish the dial was larger with better marks like a woodstock.

Just because the cat temps are low doesn't mean it's making a mess. If the combustor temps are low at the end of the burn, all the moisture is already consumed earlier in the burn and the PM is nearly zero. A low combustor temperature reading in the early part of the burn is not a good sign...and definitely can make a mess.

BKVP

 

[Bill in the U.P.]

Thanks to all. With our season coming to an end it might be next burning season before I can spend more time on this.

 

[BKVP]

Thanks to all. With our season coming to an end it might be next burning season before I can spend more time on this.

We'll be here to help.

BKVP