My not so great experience with FPX catalyst insert - Advice?

clydesdale said:

Do I really need the damper? I would hate to go mucking with this thing if it is not truly necessary. What are the advantages and disadvantages of a draft that may be too strong? I can choke the fire out by closing off the air. Only rarely will I open the door and get a little smoke on initial start up.
How hard is it to really measure the draft?
What are the advantages and disadvantages of steel vs ceramic and the cost difference? Will steel allow me to be less neurotic about MC content and wood quality?
Thanks to everyone for help with this thread. I am learning a ton and will likely call Travis after the holidays.

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It sounds to me that your draft isn’t an issue really, since you have full control over the fire.
I’ve never ever been that picky about the wood going into any of my stoves. If I had to sort through the wood, testing for moisture before throwing it in, I’d quit burning wood. You are making this way too difficult!

clydesdale said:

Do I really need the damper? I would hate to go mucking with this thing if it is not truly necessary. What are the advantages and disadvantages of a draft that may be too strong? I can choke the fire out by closing off the air. Only rarely will I open the door and get a little smoke on initial start up.
How hard is it to really measure the draft?
What are the advantages and disadvantages of steel vs ceramic and the cost difference? Will steel allow me to be less neurotic about MC content and wood quality?
Thanks to everyone for help with this thread. I am learning a ton and will likely call Travis after the holidays.

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Well, if you can shut it down all the way, I might disregard their advice about the damper like webby said. (Webby is a lot more of a stove expert than I am, too.)

Steel is often around $50 more than its ceramic counterpart . It doesn't change your moisture requirements, but the substrate will not crumble due to thermal shock. If your stove design is that hard on cats, steel might be the way to go when the old one dies. The manufacturer is not allowed to recommend steel to you unless they paid to test the stove's emissions with both types, but I am.

Steel heats up faster (good) and cools down faster (bad). Overall I would rate it about the same as ceramic for my application. Sounds like it might be significantly better for yours.

clydesdale said:

It looks like Condair has a ceramic cat for me for $425. I don't see them offering a steelcat for it. Is there elsewhere to buy these things. Damn, $425 seems high.

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That’s crazy!

After 2020 all the Hearthstone stoves will have a cat with no protection just like Lopi, unless they make some changes before then...

Email or call Condar. Condar is very helpful with figuring out what fits your stove, and it's not all listed on their website. They are however not the cheapest.

Firecat has lower prices for the same items, but they have not yet figured out how to E- the mails, or answer inquiries submitted to their World Wide Intartubes Cybersite. (They also had problems working the telephone last time I tried to buy from them..... maybe they have a telegraph station address that they do most of their business through or something.)

Carlv123 said:

Could you provide me with your cat temps at different intervals? I'm having issues with the stove dropping from 1200 to 547 within 45 min of reducing the air. Dealer says it's a draft issue but I'm lost as to the logic.

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Yeah, that's not a good temperature. Stove designs vary, but I’d expect all to run between 700 and 1200F in the first few hours of a burn, if the probe is properly located 1.5 inches behind center of face of cat. But that said, I have observed this behavior under several different circumstances:

1. When the cat is plugged with fly ash. If there's a good seal (eg. gasket) around your combustor preventing any exhaust gas path around the outside of the combuster, then a plugged cat is very easy to detect. You'll notice the stove burning very lazy, as if it's on a lower setting, even when the air is set to a very high setting. With my 30 foot chimney, I have observed this behavior several times.

2. When I try to burn wet wood. At low burn rates, the water baking out of the wood is generating steam cool enough to knock the cat out of active reburn. Given the insane amount of rain I have had this summer/fall, I have run into this once or twice this fall, even though I'm burning wood that's seasoned more than 3 years. Simple solution is to burn the stove on a higher setting for long enough to bake sufficient moisture out of the wood, usually at least 30 minutes in my stoves. Just be careful not to lose control of the thing, if you stove doesn't have a limiting thermostat (a'la BK).

3. Poor draft. Simply put, your draft limits how low you can run the stove without stalling it. If you find the cat stalling, mark your air control lever setting (I use small triangles of colored electrical tape as pointers), and try running it a hair higher the next time. The lowest setting at which you can run without stalling is somewhat weather-dependent, you can run lower as it gets colder outside. This is easy to debug with a manometer, if you're much lower than .03" WC, then this is likely your issue.

4. Cat end of life. I just replaced both of my cats, after 3 and 3-1/2 years of use, respectively. The one that I stretched to 3-1/2 years was doing exactly as you describe, falling out of active a little earlier. The new combustor can stay active until I'm down to baseball-sized coals.

There may be other possible causes for your issue, these are just the four I have experienced myself, in 14 years of running cat stoves (or 7 years of running two at a time). Three of the four are pretty easy to determine on your own, the fourth requires a new cat to prove out.

clydesdale said:

It looks like Condair has a ceramic cat for me for $425. I don't see them offering a steelcat for it. Is there elsewhere to buy these things. Damn, $425 seems high.

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I’m pretty sure your cat and mine are the same one. I paid $250 for mine at the dealer try there first. There is no steel cat that I know of I already looked around I wish there was though. This website lists it at what I paid but they used to say they won’t deliver to you out if your out of state so I never did. Now I don’t see it.

https://www.rockymountainstove.com/avalon-lopi-catalytic-combustor/#description


Lopi Rockport
Blaze King Ashford 25

clydesdale said:

Which FPX do you have? My cat temps will hold steady for quite a while. If I run it up to 900-1000, I could then have the air cut off too 80% closed and that seems like a sweet spot where it will keep temps in that range for a couple of hrs with no trouble. They then slowly decline. They would not decline to sub 600 for a good 4hrs plus.
How much are you cutting the air? I used some nail polish and marked 5 lines on the air rod. 5th line is completely choked down. I run it at 3.5 - 4 lines when the stove is up and running. Just opening from 4 to 3.5 makes a big difference and gets my cat temps much hotter. I have been keeping my temps at 1000 or less based on changing information from my dealer.

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I have the Large flush hybrid fyre. I've been going back and forth with my dealer about the short burn times and low temps. I can get the temps up to 1200 but once I pull the dir down, they drop like a brick. For example, the other night I had the probe at 1221, pulled the air supply out and within 15 min the temp was 948. 30 min and the temp went to 725 and at 1 hour the temp was 537. I was burning a combo of oak and locust with a moisture content of 19-22%.

The dealer thinks I need a damper but If the temps are not staying up, I'm not sure if this would help unless the air from the secondary tubes is drawing too hard and cooling the cat.

Any suggestions are appreciated.

Thanks

Carlv123 said:

I have the Large flush hybrid fyre. I've been going back and forth with my dealer about the short burn times and low temps. I can get the temps up to 1200 but once I pull the dir down, they drop like a brick. For example, the other night I had the probe at 1221, pulled the air supply out and within 15 min the temp was 948. 30 min and the temp went to 725 and at 1 hour the temp was 537. I was burning a combo of oak and locust with a moisture content of 19-22%.

The dealer thinks I need a damper but If the temps are not staying up, I'm not sure if this would help unless the air from the secondary tubes is drawing too hard and cooling the cat.

Any suggestions are appreciated.

Thanks

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I’m sorry if this has already been reviewed, I’m too lazy to look, but how are you measuring moisture content? Meters are calibrated at 70F, and will measure low on cold wood. Also, you need to test on a freshly-split face.

Short burn time combined with a cold combustor is a rare combination. What is the size of the firebox, and what sort of burn times are you seeing?

I do measure on a fresh split with a meter I got from Home Depot, I forget the brand. I believe the firebox on these are 3 Cu ft and I'm getting 4 hours at best.

Carlv123 said:

I do measure on a fresh split with a meter I got from Home Depot, I forget the brand. I believe the firebox on these are 3 Cu ft and I'm getting 4 hours at best.

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What size are your splits how much are you putting in the fireplace? My rockport claims it is 2.15 and my bk is 2.3. I can fit twice as much in the bk than the rockport due to how the rockport is shaped.


Lopi Rockport
Blaze King Ashford 25

Kick that cat to the curb and run wild and free like my flush wood plus! Seriously though, might be a dumb question but how big is the difference in performance if you run without the cat? Is that even possible?

Hot Stuff said:

Kick that cat to the curb and run wild and free like my flush wood plus! Seriously though, might be a dumb question but how big is the difference in performance if you run without the cat? Is that even possible?

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No, not designed to be run like that, could do more harm, best bet us to figure out what the problem is.

clydesdale said:

Update - my dealer called me back and now states that 1200 temps are fine and that 1500 is where you ruin it. I have never run it anywhere near 1500. When the cat was new it did hit 1200. Tonight with the air at 60% closed, I hit 1000. It is much better since cleaning it and I do believe that some ash could have been clogging it. When I crack the door open, I do see some ash get sucked up. But, the cat now glows from end to end. Before I cleaned it, only the center glowed. Also, flame certainly can reach the cat, so I now slow the flames way down if the fire is roaring, then I engage the cat. The stove is about 25 months old. Do I push for a new cat? All I need is the part, I can install it easily.
I bring my firewood inside and it is in the teens. I measure the MC on both sides of the split. I then rorate the wood to be in front of the insert to dry out more. I do this because I am paranoid about the moisture. I then measure the wood before it goes in. That is when I get the single digits. So, maybe that is not fully accurate. But, the wood is at worst in the higher teens.

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I don't get it., when i zap the CAT with IR gun at 550-650 and it's the same as the firebox, 3 hrs. later is all the same, heat output is crank'n, fire is going great, I just turned on the whole house fan to bring in fresh air and cool it down, hahah

I'm going to try calling Lopi tomorrow and see what they suggest. This thing either rips through wood or stalls and the dealer hasn't been much help except suggesting a damper.

Carlv123 said:

I'm going to try calling Lopi tomorrow and see what they suggest. This thing either rips through wood or stalls and the dealer hasn't been much help except suggesting a damper.

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Perhaps it’s becuase this is not a cat stove. It’s a hybrid. I’m not sure why everyone expects long burns out of these hybrids? They have tons of air pouring through them. The cat can’t sustain itself once the primary air is reduced. The cat is in this stove to act as a scrubber in order to reduce emissions, not extend the burn times like a traditional cat stove.
If you reduce the air, the cat will glow only for a short time after the secondary flames finish ripping through the cat. Then the cat temps start falling. This is even more common once the cat gets a few seasons on it.

webby3650 said:

Perhaps it’s becuase this is not a cat stove. It’s a hybrid. I’m not sure why everyone expects long burns out of these hybrids? They have tons of air pouring through them. The cat can’t sustain itself once the primary air is reduced. The cat is in this stove to act as a scrubber in order to reduce emissions, not extend the burn times like a traditional cat stove.
If you reduce the air, the cat will glow only for a short time after the secondary flames finish ripping through the cat. Then the cat temps start falling. This is even more common once the cat gets a few seasons on it.

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I'd be happy with 8 hours times but 4 is ridiculous, especially for the price. Had I known, I'd have gone with a different insert.

webby3650 said:

Perhaps it’s becuase this is not a cat stove. It’s a hybrid. I’m not sure why everyone expects long burns out of these hybrids?

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The long burns are expected because Travis rates the large hybrid with an "up to 12 hours" maximum burn time and my medium plus at 10 hours. Now granted, that is under ideal conditions with ideal wood, and I don't know what "burn time" means - when the coals burn all the way out? when it's time to reload? I'm not arguing your point, just thinking this is why there is an expectation of longer burn times.

webby3650 said:

The cat is in this stove to act as a scrubber in order to reduce emissions, not extend the burn times like a traditional cat stove.

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If that is the case, then it sounds like I'm fortunate to have the stove designed without a cat. Although, I'm guessing mine will be gone for 2020.

Hot Stuff said:

The long burns are expected because Travis rates the large hybrid with an "up to 12 hours" maximum burn time and my medium plus at 10 hours. Now granted, that is under ideal conditions with ideal wood, and I don't know what "burn time" means - when the coals burn all the way out? when it's time to reload? I'm not arguing your point, just thinking this is why there is an expectation of longer burn times.



If that is the case, then it sounds like I'm fortunate to have the stove designed without a cat. Although, I'm guessing mine will be gone for 2020.

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You made the better choice in my opinion. Maybe not real long burn times, but a beautiful fire and respectable heater! Most manufacturers put unattainable burn times on their stoves unfortunately.

I swear manufacturers should be held liable for exaggerating the specs of their stoves. I could understand a 20 even 30 differential but 60-70% is a crock.

Carlv123 said:

I swear manufacturers should be held liable for exaggerating the specs of their stoves. I could understand a 20 even 30 differential but 60-70% is a crock.

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When some manufactures over rate their product, it is hard to make them liable cause they say, UP TO......., not, you will get this hrs for sure and all the times.
Now, you need to take into consideration that, the setup and heat demand vary and is not the same for everyone.
Some with tall chimney can go through wood faster than other due to overdraft etc. Some have higher heat demand than others and can be many other variables.

lsucet said:

When some manufactures over rate their product, it is hard to make them liable cause they say, UP TO......., not, you will get this hrs for sure and all the times.
Now, you need to take into consideration that, the setup and heat demand vary and is not the same for everyone.
Some with tall chimney can go through wood faster than other due to overdraft etc. Some have higher heat demand than others and can be many other variables.

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I'll check with the manufacturer. The dealer thinks it's an overdraft issue because of the 30ft chimney. I guess I will see.