Princess burning poorly when I close the bypass damper

[jdr7]

Hey everyone! We're wrapping up our second season with our Blaze King Princess 32. Up until a few weeks ago, it's burned amazing. Hot, long burn times, etc. Lately, the cat thermostat goes up very slow and the fire looks "choked" when the bypass damper is closed. We barely get any flames, and it takes a long time for the cat thermostat to even get in the middle or top 2/3's. On high, it looks the same as when we set the thermostat to low. It usually showed really bright flames.

Our typical process is: wait to reload until cat is reading active, but low (a bit above inactive) > turn thermostat on high > wait a few minutes > open bypass damper > wait a minute > open door and reload full (while still in active) > close bypass damper > let run on high for 25 min > set to desired temperature.

I've read a bunch of threads here and come to the conclusion that it could be:

1. Cat needs to be replaced. Though seems strange, given it's only our second season and 9k hours total. It doesn't look cracked, though I haven't closely inspected it.

2. Something is wrong with the bypass damper door, and messing with the airflow. One time a few months ago we accidentally left the bypass damper open all night after reloading before bed. It worked fine until a couple weeks ago, so I'd be surprised if that is it, but I guess we could've warped or broken something?

3. Chimney needs cleaned. For both seasons, we didn't know you weren't supposed set the thermostat all the way low. This forum educated me to only set on the lower third or so, so that we don't get creosote build up. We've been doing that, but I do wonder if doing it wrong all this season maybe built up a lot and now we're just getting bad burn times.

4. A seal or gasket of some sort needs to be replaced? I really don't know what I'm doing, just trying to learn.

Other relevant details: 15' chimney, 2 year stacked and split wood reading at 13% moisture.

We're about to shut it down for the season and have the chimney cleaned, but I wanted to ask around here to make sure we check everything that might be wrong so we can fix it this summer. Thanks in advance for any guidance or help!

 

[all night moe]

Sounds like poor draft or, subpar wood.

 

[Todd]

How often do you brush off the cat?

 

[kborndale]

When the temps warm up your draft will decrease significantly.

 

[stoveliker]

Looks like poor draft or poor wood. Could be due to blockages and/or warmer temps outside.

I'd check the chimney. Binoculars for the cap. Going one full night with the bypass open (and the air low) can result in significant build up already.
Is the cat clogged with ash or other?
Is the wood measured (13%) *on a freshly split surface*?

Leaking seals generally speed up burning, so unlikely imo.

 

[jdr7]

Sounds like poor draft or, subpar wood.

Thanks! Our wood is reading 13% split, so maybe poor draft due to too much build up.

 

[jdr7]

Looks like poor draft or poor wood. Could be due to blockages and/or warmer temps outside.

I'd check the chimney. Binoculars for the cap. Going one full night with the bypass open (and the air low) can result in significant build up already.
Is the cat clogged with ash or other?
Is the wood measured (13%) *on a freshly split surface*?

Leaking seals generally speed up burning, so unlikely imo.

Thanks! This is super helpful. I don't think it's poor wood since it's very seasoned, and seeing recurring replies about the poor draft. Just trying to narrow it down, and grateful it may not be seals. My guess is that after burning it too low (basically smouldering all night, most of the season) we probably built up a blockage. I'm hoping it's that combined with warmer weather. I'll take a look - we're getting our chimney cleaned in a few weeks too, which should help.

 

[jdr7]

When the temps warm up your draft will decrease significantly.

Oh wow, I didn't know that. Good to know.

 

[jdr7]

How often do you brush off the cat?

I'm not sure what that means, so... never

What does that entail? How often should we be doing it? Going to look into this now...

 

[begreen]

I'm not sure what that means, so... never

What does that entail? How often should we be doing it? Going to look into this now...

Page 32-33 of the manual covers this.

What is the flue setup for this stove. Can you describe it from stove top to chimney cap including any elbows or tees and the length?

 

[all night moe]

or, subpar wood

Our wood is reading 13% split,

Subpar wood could also be a factor of species.

13% MC of box elder is a fart in the wind. Some other woods will net the same results. You can grab a bag or two of convenient store wood or some bio-bricks to rule this out. Warmer temps, especially on a damp day, will hinder draft. Once the flue heats up good, it should pull draft well. It maybe a combo of both, draft and wood.

 

[Tron]

and it takes a long time for the cat thermostat to even get in the middle or top 2/3's. On high, it looks the same as when we set the thermostat to low. It usually showed really bright flames.

Ignore the cat thermostat, only use it to determine whether the cat is in the active range or not. Other than that, no useful information can be derived by that.

But if you don't see vigorous flames with the thermostat wide open, it may be stuck. Do you hear the "click" when you close it?
To test it, you can open the cover and temporarily wedge it wide open. See if that helps.

 

[Highbeam]

These new princess stoves all ship with a fine mesh steel cat. First step is to inspect it for plugging. They can plug front and back and sometimes all the way through with ash.

If you have a filter on your chimney cap it could be clogged. This is a maintenance item too and is usually optional. If so for you, I would opt out of a cap screen.

We burn well into June and often at warm outside temperatures. Other than smoke rollout during startup, everything works just fine once the fire heats up.

I would wager your cat is plugged up. Next time you replace the catalyst I recommend the ceramic option with bigger holes.