Digital Cat Thermometer

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NinjaTech

NinjaTech

Burning Hunk
Oct 30, 2014
151
Saint Louis
First off I would like to say "hello" to everyone on the forums. I have been doing a TON of reading on here about what stoves people like, and how to properly run a cat stove. Love the forum! This will be my first post.

When I was growing my family had an old non EPA insert that we used for our primary heat during the winter. I always loved that thing as a kid, to me heating with wood just has so much more character to it than setting a thermostat on a gas furnace. I finally had an opportunity to purchase my first wood stove for my own house. I decided on going with a Blaze King Princess insert. I have it heating a 1,500sf single story with full finished basement. Its on the first floor of the house so I don't know how well it will do getting heat down stairs this winter, but we will find out! I have a direct vent gas log fireplace down stairs I can use for supplemental heat during the night when I'm home if I need it. I put it in about two weeks ago with a insulated SS liner and all I can say is wow! So far it hasn't been under about 40, but I'm looking forward to the temps heading towards zero this winter so I can let this thing stretch its legs a little.

With enough searching on the forum I have been able to pretty much answer every question I had in regards to proper running, but the one thing I didn't see very much was digital cat thermometers. I wasn't very pleased by the thermometer that came with the stove. It was the usual BK "inactive" "active" thermometer that doesn't even hint about actual temperatures. I went and did some looking to find a much more accurate digital thermometer, but there are not many out there. Almost all of the ones I found were battery powered, and would automatically shut themselves off after a while to conserve battery power. I was looking for something I could see from across the room, without having to walk over and push a button to turn it on. What I ended up going with was a thermocouple setup that's designed for pottery kilns. Its AC powered, and does not automatically shut off. As long as its plugged in, it shows the temp. I did have to change out the actual thermocouple that came with it, the kiln style one just wouldn't have properly fit the stove, and I didn't want to actually cut metal and either ugly up the stove, or void warranties. Ebay has a TON of various K style thermocouples in pretty much every shape and size you can imagine so I found one that has the same length probe as the stock BK thermometer, and was rated for 2,000F and it fits right in. Now I have a to-the-degree measurement of cat temps. It also has a high temp alarm that can be set so if the cat gets too hot, the thing will start beeping like crazy. I like that the stove will now yell at me if I let it get to warm.

That brings me to the actual question, since its still fall and I am having to keep the stove set just about as low as it will go, whats the lowest I can safely run it without risk of crudding up the cat? I know light off temp is around 500, but after its going what do you guys normally consider the 'lowest' it should be kept idling at?

If anyone is interested in the thermometer its a Auber AT100

Thanks,
Patrick

[Hearth.com] Digital Cat Thermometer

[Hearth.com] Digital Cat Thermometer

[Hearth.com] Digital Cat Thermometer
 
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As far as I can tell the temps are dead on. I don't have any good reference since the stock thermometer doesn't have any numbers on it. I did test the thermocouple before putting it in using ice water (32F reference) and boiling water (212F reference) and it was dead on for both those. The hole for the thermometer on mine is about an inch downstream of the cat, so its between the catalyst and the flue. I'm not quite sure, but the stove has a piece of angle iron welded to act as a shield between the cat and the probe tip. I'm guessing probably to make sure its reading actual exhaust gas temp and not being affected by infrared radiation from the back face of the cat. Mine normally shows 500-1,250F. The cat starts to have a faint glow around 1,000, and its a nice orange by ~1,200. I did take an IR thermometer to the top of the stove, and it reads right about half what the thermocouple reads so that leads me to believe that its pretty accurate. Most places I have seen say stove top temps are normally around half the cat temp.
 
The max alarm is why I wanted a digital on mine, the AT100 does a great job of that. I just bought a different thermocouple from Auber, I am going to try measuring my temps from the exhaust collar to see if I can find a correlation there. I have gone through 4 K type probes so far trying to find something that worked, all measured the same too low of temps when compared to the condar catalytic probe. I even talked to BK about it and they only use the bi-metallic so I pretty much gave up.
 
If your not wanting to punch more holes in your stove to move it behind the cat, what about running the wire down between where the flue connects to the back of the stove and putting the probe right behind the cat that way? Maybe make a little metal bracket to hold the tip of it up in the air so its not resting on the floor of the smoke channel. Not sure how your stove is constructed on the inside so I don't know if there will be bypass doors in the way or not. Just an idea. Any gap the wire leaves in the flue, just fill with furnace cement.
 
Is the wire on yours insulated with some kind of rubber? The wire that came on mine is insulated with fiberglass between the two conductors, and then a braided SS cover over the entire thing. I got it for 15 bucks or so on ebay, you could always grab a cheap one and give it a shot. Maybe it will hold up better than you think, worst case your out 15 bucks and a bit of time putting it in.
 
NinjaTech said:
I wasn't very pleased by the thermometer that came with the stove. It was the usual BK "inactive" "active" thermometer that doesn't even hint about actual temperatures.
Click to expand...

Sure it does, didn't you see the little white ticks around the edge of the meter? Then take a look at a normal condar cat probe meter with numbers. Neither matters since the only important thing is that the stat stays in the active range.

The coolest thing you found is a digital meter that can be read from across the room. I would be more interested in flue temps, or surface temps though.
 
Got and IR thermometer for that! I guess I could get more thermocouples and just stick them all over the thing, but then it might start looking too much like frankenstove. One for flue temp might not be a bad idea though since its a insert and you can't see the flue with the surround on it.
 
Not just the wire, guys, but most of those K-type probes will fall apart after a few months at +1000F. I went thru several, before I sought help from Omega Engineering, to have specialty probes made. Very few probe assemblies can endure the full range of temperatures over which the K-type junction is rated.
 
I am curious to see if you installed a flue thermocouple? I have mine up and running and I am seeing higher temps than I thought I would at my appliance connector, temps in the 400-450 range with the cat running at around 1300. I have found it interesting, more I increase the air on mine the higher the chimney temps but the cat stays at about the same temp, seems to just shoot more of the heat generated up the chimney.
 
Joful said:
Not just the wire, guys, but most of those K-type probes will fall apart after a few months at +1000F. I went thru several, before I sought help from Omega Engineering, to have specialty probes made. Very few probe assemblies can endure the full range of temperatures over which the K-type junction is rated.
Click to expand...

Defently need an Inconel probe at these temps . Omega and Temprel both offer a complete line of Inconel K Type Probes. We use only Omega for our Catalyst Testing. Running in the 1000 C range.
Anyone ever measure the Cat bed temp ? Center of brick. I am looking for an idea of what temp range the Cat is seeing without instrumenting up my stove.
I could probally sneak a long 1/16 probe down threw the top hole and into the center of the brick. I may try a different Technology Catalyst for the heck of it.
I just need to map out the temps it will see.
 
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Joful said:
Not just the wire, guys, but most of those K-type probes will fall apart after a few months at +1000F. I went thru several, before I sought help from Omega Engineering, to have specialty probes made. Very few probe assemblies can endure the full range of temperatures over which the K-type junction is rated.
Click to expand...
Jotul,
Your comment should be also posted in the VC 2014 thread. It is being discussed as well.
Thanks
 
Feel free to repost or link there! Do note those 1/16" dia probes fail at temperatures the 1/4" probes can easily handle, all materials being the same.
 
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This is a great install. I too am sick of getting up to go over to the stove to see the temp. I think I will be buying one of these.

Question on the install and the second photo. You show it hanging next to the insert maybe 8"ish away from the insert. How hot is it in that location? What kind of temps can the unit itself take.

Thanks for sharing.
 
Sorry guys that I'm reviving this thread. It's just that I can't find the option of making private messages here (or just don't have the privilege yet) so I'd be able to directly ask NinjaTech about this. He's also not been active for a while (too early in the season?).

But do anyone of you guys know the exact thermocouple probe that Ninjatech used for his Auber AT100 that exactly fits the slot for the oem cat thermometer of the bk princess insert? He mentioned it on his first post but missed posting the model or link.

@ Ashful: mentioned about custom thermocouple from Omega Engineering. Can you guide me on that one?

Thanks guys.
 
Any updates on success of digitally monitoring temps
 
devros said:
Anyone have any model #s on the probes they went with for mounting right behind the cat?
Click to expand...
This is an old thread. Can you start a new thread with your stove make and model and put Digital Cat Probe for xxx(stove model) in the title? That should get more attention.
 
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