Are these the symptoms of a plugged cat

[Jeff in Maine]

I have a Princess of 2015 vintage I have changed the cat from Ceramic to Metal Monolith Cat a few years ago. In the last 3 weeks I have noticed some strange things that have not happened before.

1) I smell smoke when the stove is turned down to about the 3-4 o-clock position during the overnight or when we come back after being away a few hours. Door seal and By-pass seals are in good firm contact thus the "Dollar Bill Test" done this pre season.
2) The Cat does not stay active when the thermostat is turned down to 4 and below
3) Right now, the stove is WOT and there are barely flames visible inside compared to the wild roaring flames usually present at WOT. I never run it at WOT as a daylong setting, only for startup and charring the new loads. If turn it down to 3-4 it will not stay active.
4) Yes the chimney is clean just cleaned it this morning have not shoveled out the crap yet but the flue is open.
5) Yes the wood is extremely dry over 3.5 years of split stacked under cover. Lots of drying cracks (checking) on the butt ends.
6) I have burned maybe a pickup truck load equivalent of seasoned white Fir between last year and this winter, would that provide enough fly ash to plug the cat?
7) I did not blow out the Cat before this burn season, so it has about 8,500 or 9,000 hours of burn time on it without blowing it off. Is this the issue??
====================================================
I was wondering if I can blow compressed air through the front of the Cat backwards through the Cat? Even if I can It will be Sunday Noon or after before the stove is cool enough to try that.

***UPDATE*** I just did some math, that Cat gets about 4,100 hours of use per season. It has been in the stove for 3 complete seasons so it now has over 12,000 hours on it I bet it needs to be replaced.

 

[stoveliker]

Yes, to me (wot not raging) indicates lack of air flow.
If the chimney (and cap!?) are clear, it's most likely the cat.

A plugged cat also will see insufficient fuel to stay active at lower settings.

At the age of the cat I would get another one in the shelf so you can exchange when it's needed.

 

[Jeff in Maine]

Yes ,I will order one later today most likely. Sometimes I just need to put all my thoughts down on paper to grasp the results.

 

[Jeff in Maine]

The one on the Left is before blowing off. /// the one on the right is after blowing off. The cat is active but barely it is at about 575* after WOT for 15 minutes. The thermostat is at 3.5 now and there are no flames inside the Cat is not glowing.

I do have a question, when I buy the new Metal Cat the gasket comes separately in the box it says (Midwest Hearth). The last time I tried to put a gasket on a cat it was a Ceramic one that I had removed from use for some reason cannot remember why now. Anyway, before I was done that cat was ruined, I took my time and snuggly taped the gasket to the cat using Green Frog tape folded corners trimmed closely it looked perfect to me, but I could not get that cat back into the opening. I REALLY DREAD trying that again, am I using the wrong tape? Do any of you have any tips. Last time I cleaned the opening with steel wool then a clean rag that spot was, spotless and I still could not get that cat into that opening.

 

[stoveliker]

The pre-blowing cat looks fine on the surface. Of course we don't know what was in the channels and at the back side.

I had no trouble sliding my (same) cat back in with a new gasket. Interam gasket is what you need. I bought a roll (forgot how much, 20 ft or so) separate from the cat but the gasket that Midwest hearth sends should be the same

 

[stoveliker]

But regarding your temps, the other thread suggests you have a plugged cap or so. I do think that is consistent with the observations listed here.

 

[Jeff in Maine]

I only know of one gasket?? (Interim gasket) I just mean as described above that the last time I did this I tapped the gasket to the cat as good as I could and still it did not want to slide back in. As far as a "CAP" I have none like you mean with the screen on all sided I presume. Mine is a roof over the flue top supported about 8" or so above the flue top by 4 legs. No screen at all. the chimney is clean Like I said earlier I cleaned it yesterday.

 

[stoveliker]

I think I mixed up cases.
The one gasket is an Interam (name, not typo) gasket.
Some simple masking tape on the back of the cat should work.

If your cat comes out with difficulty too, I wonder if the housing is deformed?

 

[Jeff in Maine]

The time I took the one out it came out just fine. I believe I used Frog tape last time, maybe it is thicker than just the tan masking tape?

 

[stoveliker]

Ok. I have never used frog tape.
I'd get the cheapest tan paper like tape from a store.


WOT for 15 minutes from a cold start and then at 575 I think is low but it depends on the load and the draft.
Cat does not need to be glowing for it to work.

 

[Jeff in Maine]

When I remove my pipe for cleaning i always place a sheet of tinfoil over the thimble while the pipe is removed. I get the sheet to within 6" of the hole and the draft will suck the tinfoil right up to the hole and keeps it there. I have plenty of draft I have no way of knowing how much and I assume it gets lower and higher depending on the weather.

 

[stoveliker]

That does sound good. Though if it's too high you could suck ashes in the cat

I've been burning spruce lately and I notice that it gives very light flaky ashes. I took out my cat a couple of weeks ago and found some ashes in the bottom 1/4 of the cat, but only in the back, invisible on the front.

If you don't want to take the cat out, take the pipe off place a light in front of the car and look with a mirror from the back to see if your back see through the cat.

I do think it could also be consistent wit an end of life cat though that seems a bit early for my taste.
I'd order one sooner than later, get enough gasket, replace the cat. If that resolved it, then that was likely it (unless it bsee issues after taking the old one out.)

 

[Highbeam]

The ceramic cats come with the gasket pre installed, are cheaper, bigger holes less likely to clog, don’t distort/melt, and in my experience they last longer. Have you considered going back to ceramic?

 

[Jeff in Maine]

My wife has an illness that causes among lots of other things for her to be pretty sensitive to the cold. That means lots of wood put through the stove on cold windy days. That means not being able to wait for the cat to become inactive before reloading. That means opening the door on a hot cat and that means thermal shock and crumbling cat. During cold windy weather I run the stove on the 5 or 5:30 position, 6 being WOT.

 

[Jeff in Maine]

unless it bsee issues after taking the old one out.)

I don't know what you mean

 

[stoveliker]

I am sorry to hear that.

But I never wait till it's inactive. I prefer to reload with it active; quicker a clean exhaust.
I open the bypass, wait a few minutes, then open the door reload, close the door, and once flame is there close the bypass after a minute or two.

 

[stoveliker]

I don't know what you mean

Sorry, fat fingers.
Unless you see an (other) issue after taking it out.

 

[Jeff in Maine]

got ya