Regency Catalytic Hybrid Stove - expected behaviours

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New Stove Guy 2020

New Member
Nov 27, 2020
16
Sea to Sky, BC
Hi there,

I have a catalytic stove (Regency F2500). I believe it's working well as there is no real visible smoke from chimney when cat is engaged (which is different to when the cat is bypassed during fire-up), and I think I'm getting good burn times - but I need to ask some "stupid" questions to put my mind at ease. I hope that you'll humour me:
  1. When you engage the cat, would you expect the probe thermometer to react/spike? The catalytic flue collar thermometer that was supplied with the stove that I have does not change when the cat is engaged. The flue thermometer is consistent with the stove-top thermometer (goes up as the stove temperature goes up, drops as the temperature drops) - see pic
    1. Would you expect the flue collar thermometer to remain higher as the wood burns down and the stove temperature drops?
  2. The flue-collar thermometer provided has an 'active' and 'inactive' range - see pic, so I can't tell what the temperature is. Would anyone recommend switching this out for a thermometer (that provides the actual temp), or adding a second thermometer further up the flue?
  3. I get a burn time of around 8-10 hours (overnight) - meaning that after that time in the morning, the stove is hot/warm to the touch and there would be a few coals in the stove that could be used to strike up another fire. The stove and flue temp would be dropped to low. I'm assuming that this would be 100% expected? From here the course is to restock the fire, sustain a temperature of 500-700 (stovetop) for 20-30 mins before re-engaging the cat.
  4. Regarding Burn times - I'm adding new wood to the stove 4-5 times a day to maintain a consistent temperature, and then the stove runs down overnight. Does this sound consistent with other's experience?
Anything else I should look out for.
Many thanks for any feedback in advance.

PXL_20201202_220838940.jpg
 

Highbeam

Minister of Fire
Dec 28, 2006
19,349
Mt. Rainier Foothills, WA
Hi there,

I have a catalytic stove (Regency F2500). I believe it's working well as there is no real visible smoke from chimney when cat is engaged (which is different to when the cat is bypassed during fire-up), and I think I'm getting good burn times - but I need to ask some "stupid" questions to put my mind at ease. I hope that you'll humour me:
  1. When you engage the cat, would you expect the probe thermometer to react/spike? The catalytic flue collar thermometer that was supplied with the stove that I have does not change when the cat is engaged. The flue thermometer is consistent with the stove-top thermometer (goes up as the stove temperature goes up, drops as the temperature drops) - see pic
    1. Would you expect the flue collar thermometer to remain higher as the wood burns down and the stove temperature drops?
  2. The flue-collar thermometer provided has an 'active' and 'inactive' range - see pic, so I can't tell what the temperature is. Would anyone recommend switching this out for a thermometer (that provides the actual temp), or adding a second thermometer further up the flue?
  3. I get a burn time of around 8-10 hours (overnight) - meaning that after that time in the morning, the stove is hot/warm to the touch and there would be a few coals in the stove that could be used to strike up another fire. The stove and flue temp would be dropped to low. I'm assuming that this would be 100% expected? From here the course is to restock the fire, sustain a temperature of 500-700 (stovetop) for 20-30 mins before re-engaging the cat.
  4. Regarding Burn times - I'm adding new wood to the stove 4-5 times a day to maintain a consistent temperature, and then the stove runs down overnight. Does this sound consistent with other's experience?
Anything else I should look out for.
Many thanks for any feedback in advance.

View attachment 268286

The F2500 is a 2.3 cubic foot stove and is a hybrid stove. I would expect the cat probe meter to climb when the bypass is engaged, mine on my actual cat stove sure does. It goes all the way to near the top and stays there. The catalyst active line should correspond to 500 degrees and the top of the active scale should correspond to about 1500 degrees. I replaced my original unlabeled cat thermometer with a new one that is identical looking and from the same company but that is numbered because I like numbers. Condar makes these.

Barely getting through the night with 2.3 cubic feet is more of what I would expect from a regular noncat stove at it's lowest burn rate. A good cat stove of that same size should be able to easily get 20 hours of burn time at it's much lower lowest burn rate. If you need the heat that this F2500 offers then both stoves will make the same amount of heat in the same burn time if set to the same burn rate.

I think Regency added a cat to a noncat stove to get lower emissions but did not design this stove to offer the low output necessary for a long burn time. If you wanted long burn times, there are other stoves that are made to do this well at a correspondingly lower output rate.
 
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New Stove Guy 2020

New Member
Nov 27, 2020
16
Sea to Sky, BC
Thanks for the reply.

In your estimation it seems that I'm not getting the performance from the stove I should be which is good to know, although it's worth flagging that Regency state on their website that max burn time for the stove is 12 hours - which I'd assume is in optimal conditions, so 10 doesn't seem too bad?

More concerning for me is the lack of temperature spike with the cat thermometer when the cat is engaged. Any thoughts on why this could be, and how I can fix? Just to note also:
  • Wood is dry
  • I get stove up to heat (500-700), and let it sit there for 20-30 mins
Thanks
 

begreen

Mooderator
Staff member
Nov 18, 2005
90,660
South Puget Sound, WA
Have you visually checked the bypass mechanism to make sure it is working and sealing correctly?
 
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Highbeam

Minister of Fire
Dec 28, 2006
19,349
Mt. Rainier Foothills, WA
Thanks for the reply.

In your estimation it seems that I'm not getting the performance from the stove I should be which is good to know, although it's worth flagging that Regency state on their website that max burn time for the stove is 12 hours - which I'd assume is in optimal conditions, so 10 doesn't seem too bad?

More concerning for me is the lack of temperature spike with the cat thermometer when the cat is engaged. Any thoughts on why this could be, and how I can fix? Just to note also:
  • Wood is dry
  • I get stove up to heat (500-700), and let it sit there for 20-30 mins
Thanks

Your stove was designed to only run low enough to provide 12 hours of max burn time. The 10 you are getting is really close. I can’t conclude that anything is wrong based on this. You were an informed buyer when you chose a hybrid with that range of output levels. Other true cat stoves have twice the range.

I do expect your cat meter to go up when a cat is engaged. Smoke free may be just be the noncat portion of this hybrid system doing its job well.

Are you certain that you are engaging instead of disengaging the catalyst?
 
Last edited:

New Stove Guy 2020

New Member
Nov 27, 2020
16
Sea to Sky, BC
I've watched a Blaze King video about operating the cat stove ().

I think my issue is that I have overly cautious in letting the cat get up to the correct temperature.
I have a stovetop thermometer - see previous pic, which always heads to 800F ("overheat") when I get the firebox started. I then in turn adjust the air damper to bring the temperature down to 600F, which requires significant adjustment.

I'm just trying a burn now and letting the stove get hotter in the inital burn phase (first 30 mins after cat engaged) than I typically would.

Have you visually checked the bypass mechanism to make sure it is working and sealing correctly?

@begreen I will inspect this next time the stove is cool. I have checked in the past that the bypass gets correctly positioned under the chimney when engaged (by removing the chimney and looking down). Let me know what else I could be looking for,

I do expect your cat meter to go up when a cat is engaged.

@Highbeam - it's going up as engaged currently. Would you expect it to sustain it's position for some time (how many hours?) once I reduce the airflow?
 

begreen

Mooderator
Staff member
Nov 18, 2005
90,660
South Puget Sound, WA
Pic: 20 mins after cat engaged (once it passed into 'active'), with air supply open
That looks better. Getting warm now? If the air is now reduced 50% does the cat temp drop a lot too?
 

New Stove Guy 2020

New Member
Nov 27, 2020
16
Sea to Sky, BC
Yep - so, after firing the stove with the air supply open for 30+ minutes after engaging the cat, I progressively adjusted the air damper to manage the burn. After 20 mins or so, both the stovetop thermometer and cat thermometer have dropped - see pic compared to previous.

For owners of a cat stove - would you expect the same behaviour, or would you expect the flue temperatures to remain at a higher temp vs. the stove top?

Thx.

PXL_20201203_035820931.jpg

That looks better. Getting warm now? If the air is now reduced 50% does the cat temp drop a lot too?

@begreen - yes the 2 temperatures seem to move commensurately
 

begreen

Mooderator
Staff member
Nov 18, 2005
90,660
South Puget Sound, WA
As long as the cat temp is in the active zone, then it's doing it's work. The wood gases in this stove are first being consumed by the secondary combustion, followed by the cat for cleanup of residuals. The catalyst in a pure cat stove has a lot more smoke to munch on. You need to ask these questions of cat-hybrid owners. That's why I added this to the title.
 
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begreen

Mooderator
Staff member
Nov 18, 2005
90,660
South Puget Sound, WA
It will be interesting to see how these readings compare with other Regency and non-Regency cat hybrids.
 

New Stove Guy 2020

New Member
Nov 27, 2020
16
Sea to Sky, BC
@begreen thanks yes it would be good to hear from other owners of similar stoves. I'll try contacting Regency and the shop where I purchased the stove to get their opinions on it's performance also.

Generally I'm very happy with the stove. It's allowed me to turn off my other sources of heat and does a good job. I just want to make sure that I'm running it optimally and identifying anything that isn't running as it should.

Cheers
 

begreen

Mooderator
Staff member
Nov 18, 2005
90,660
South Puget Sound, WA
We have a lot of new hybrids showing up in 2020 so I too am curious.
 

ABMax24

Minister of Fire
Sep 18, 2019
1,226
Grande Prairie, Alberta, Canada
As long as the cat temp is in the active zone, then it's doing it's work. The wood gases in this stove are first being consumed by the secondary combustion, followed by the cat for cleanup of residuals. The catalyst in a pure cat stove has a lot more smoke to munch on. You need to ask these questions of cat-hybrid owners. That's why I added this to the title.

I think that is exactly the reason the cat isn't getting any hotter, ideally there should be very little volatiles left for the catalyst to consume. IMO a hot catalyst on a hybrid stove is an indication of poor combustion within the firebox, and should to some extent be avoided, especially when considering on this model the heat from the catalyst goes straight up the flue.
 

Highbeam

Minister of Fire
Dec 28, 2006
19,349
Mt. Rainier Foothills, WA
Well you can see when secondary combustion is no longer cleaning any smoke, the flames go out. At that point you’re in cat only mode and cat temps should climb.

The only time my car meter falls down from almost the top is when I’m stalling it due to low intake air setting or it’s out of fuel.
 

DiBurn90

New Member
Jan 6, 2021
12
Chillicothe, Ohio
Also have an F2500 that was installed beginning of last winter. Been reading the forum a lot, lots of good advice and information here. this is my first post. First stove so I'm still pretty new to it but here is my experience so far.

I normally see a decent rise in the cat probe thermometer once it is engaged but doesn't seem as drastic as what I have read from the Cat stove posts. How quickly I shut the air down can also have a good impact on how high it climbs. I go more off the flue temp than the probe thermometer for when I engage the cat using an IR gun to take the reading.

I normally engage the cat between 350-450 (typically~400) external flue temp ~18" above the collar and it lights off pretty well normally. On a full load of hardwood (normally ash and cherry as that's what I have seasoned right now) it normally climbs up around the tick mark about the word "active" on the prove thermometer and hangs out there for a while then starts to drop as the stove does.

Normally see the stove hit up in the 700s (seen low 800s a few times) and it normally settles in the mid 600s to cruise when shut most of the way down.

After getting familiar with how the stove runs I can get 10-12 hours burns out of it pretty consistently. I think good seasoned wood is key there. I got into some boarder line stuff in the 22-26% range last spring and struggled to get more than 8-10 hours since I had to leave the air open a bit more.

Stove seems to burn pretty clean too. Had minimal/almost no build up buring ~2 cords last winter.

Sorry for the long winded post.
 

Wood Hunter

Member
Dec 29, 2014
8
F'dale, NY
Been looking at the F2500 and 1500 are you guys still happy with the 2500? They both qualify for the tax credit and I'll be pulling the trigger on a new stove soon.
 

DiBurn90

New Member
Jan 6, 2021
12
Chillicothe, Ohio
Been looking at the F2500 and 1500 are you guys still happy with the 2500? They both qualify for the tax credit and I'll be pulling the trigger on a new stove soon.
After 2 seasons using it as our primary heat source still very happy with ours. Heats our place pretty well. 2nd season with little to no build up in the stack with over 2 cords through it. No problem getting 10-12+ hours out of it with enough coals to reload on with the seasoned ash, cherry and black walnut we had for this winter.

We got a few chances to open it up some more this winter and it put out good heat. We do have the blower attachment for it, definitely increases the heat coming off the stove.

I haven't really had any issues with operating it once I got familiar with how the stove runs, seems to run pretty consistent for us. My wife was a little concerned about running it by herself at first but she was able to pick it up pretty quickly and get comfortable with it not having any prior experience. She actually chose to run it by herself for a few days when I went on a business trip last winter.