Calibrating the thermometer gauge

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tsh2002

Member
Jan 23, 2018
51
Michigan
Hello. I'm at the beginning of burning season and trying to make sure my thermometer gauge is correctly calibrated for our Ashford 30. Most of the photos I've seen here are with a different gauge than what I have (mine is about 1 year old). At room temp the needle is below the Inactive zone a small amount, photo below:

[Hearth.com] Calibrating the thermometer gauge


Should I be adjusting it so the needle is at the bottom of the Inactive zone, or leave it as-is?

Thank you very much!
 
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My Princess 29 insert thermostat looks like this when cold (no fire), room temp is 62F:

[Hearth.com] Calibrating the thermometer gauge


I'm guessing that's not right.

Stove was installed professionally in Feb 2023 and I believe the thermostat has always looked like that. Should I adjust it? I scanned the user manual and didn't see anything about what the cold thermostat should look like. I did see the forum threads that indicate that this is not correctly calibrated.
 
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My Princess 29 insert thermostat looks like this when cold (no fire), room temp is 62F:

View attachment 331525

I'm guessing that's not right.

Stove was installed professionally in Feb 2023 and I believe the thermostat has always looked like that. Should I adjust it? I scanned the user manual and didn't see anything about what the cold thermostat should look like. I did see the forum threads that indicate that this is not correctly calibrated.
You are correct, this meter needs to be calibrated. Pretty crappy that they can't just hold a zero like most any other thermometer.

WHen cold, the red needle should point to the very bottom of the inactive range.
 
You are correct, this meter needs to be calibrated. Pretty crappy that they can't just hold a zero like most any other thermometer.

WHen cold, the red needle should point to the very bottom of the inactive range.
Thank you, appreciate your reply! I did contact BK this morning via their website, and they replied to assure me that I haven't damaged my stove and sent the following instructions:

"The needle should be pointed at the first “tick” mark below the Active range. Adjusting them can be a bit tricky so you may want to have your dealer help. There are two nuts, one on top and the other on the bottom. If you ever so gently loosen the lower nut, you should be able to turn just the face of the thermostat slowly (counter clockwise) to reference the needle to the first tick mark."

Thank you to this forum to bringing it to my attention!
 
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Thank you, appreciate your reply! I did contact BK this morning via their website, and they replied to assure me that I haven't damaged my stove and sent the following instructions:

"The needle should be pointed at the first “tick” mark below the Active range. Adjusting them can be a bit tricky so you may want to have your dealer help. There are two nuts, one on top and the other on the bottom. If you ever so gently loosen the lower nut, you should be able to turn just the face of the thermostat slowly (counter clockwise) to reference the needle to the first tick mark."

Thank you to this forum to bringing it to my attention!

Well, it's actually that first tick at the bottom of the INACTIVE range which coincides with the bottom of the inactive scale.

If you break the meter during adjustment, or if you find the set point wanders, you can buy a better made condar brand cat meter with actual numbers to replace it. I have 4 different mechanical condar meters and none have ever required resetting the zero point.
 
Lol, I still wonder if BK is laughing behind the scenes when they read that ^^ because they just rebranded Condar thermometers...

BTW, the first tickmark below the Active range is the one that's also at the bottom of the inactive range.
 
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Lol, I still wonder if BK is laughing behind the scenes when they read that ^^ because they just rebranded Condar thermometers...

BTW, the first tickmark below the Active range is the one that's also at the bottom of the inactive range.
Condar might make the meter for BK, might not. I don’t recall that being announced. Whoever makes the BK cat meter certainly appears to produce the part at a lower quality level than what you can get direct from condar.
 
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More likely that these are cheap China clone thermometers.
 
I contacted Blaze King via their website and they confirmed that my thermometer gauge is correctly calibrated. I posted the photo of it at the top of this post, so hopefully this helps others that have this newer gauge as well. Thanks to all!
 
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I was able to adjust my thermometer this morning, but it didn't require loosening the lower nut. I only had to apply a gentle force to turn the thermometer face counterclockwise. Now I'm not sure if I should attempt to tighten the lower nut or leave it.

The temperatures here have been unseasonably warm, and I'm not yet running the stove 24/7. I'm thinking I'll light a fire today and let it go out after the weekend, as we're expecting warmer temperatures again on Monday. I'll have to see if the thermometer is still where I set it after the stove cools.
 
So, having both a Condar one and a BK one, I did a test today (first fire lit last night...).

I ran with the BK and swapped for the Condar (assuming 5 seconds of air sucking in the hole - I could not hear that, though - was not that bad...?).
Pics. Of course this is after 20 minutes to give the Condar time to get up to temp. BK 7.33 AM, Condar 7.50 AM.
The Condar did not change in the 15 minutes after I took the pic.

My conclusion is that the "active range" is different for the two.
My BK calibration is proper (at room temp indicator is near the little tickmark slightly below the "inactive" bar - as bkvp mentioned in this or another thread recently)

I did this test because I was running with the Condar in my small "test fire" a couple of weeks ago to make sure everything worked before I needed heat, and I thought the temp was low ("is my cat aging"?). But my BK, while certainly not high, was showing normal to slighty below what I remember from last year.
Load is mostly maple and oak, and this is last night's partial load, so it's near a small heap of coals.

I thought this was interesting to report.

[Hearth.com] Calibrating the thermometer gauge [Hearth.com] Calibrating the thermometer gauge
 
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That's helpful. Based on this it looks like the room temp calibration is closer to the end of the outer arc on the BK thermometer than to the first tick mark. That is like tsh2002's thermometer calibration.
 
I'm not sure what you are saying (or how to conclude anything about room temp from the above pics).

This is the BK that has been on the hearth pad besides the stove all day since I took it out this morning (double wall convective stove sides, so not a lo t of radiation ; pad there is 84 F according my IR gun.)

The difference between the bottom of the inactive white range and the tickmark is negligible imo.
 

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  • [Hearth.com] Calibrating the thermometer gauge
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I'm not sure what you are saying (or how to conclude anything about room temp from the above pics).

This is the BK that has been on the hearth pad besides the stove all day since I took it out this morning (double wall convective stove sides, so not a lo t of radiation ; pad there is 84 F according my IR gun.)

The difference between the bottom of the inactive white range and the tickmark is negligible imo.
Not the white range, the outer white arc, like in the OP's thermometer.

[Hearth.com] Calibrating the thermometer gauge
 
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Okay. That's not my room temp reading; mine is near the tickmark at/slightly below the bottom of the thick white inactive range.(Consistent with what bkvp said it should be)
 
I adjusted mine to the tick mark same as stoveliker's, and not the outer white arc. OP's thermometer looks different than ours, I'm not really sure where room temp should be on that gauge. (Edited to add: I see OP posted that theirs is calibrated correctly according to BK, at the end of the white arc, so I guess it depends on the thermometer you have.)

Mine seems to be holding where I set it -- I've let it go cold twice and both times it returns to the tick mark. I have been enjoying much longer burn times since adjusting. I felt like something was off before -- it was taking a long time to get up into the active range and was falling into inactive sooner than expected, maybe only 7 or 8 hours. The lowest I could set the thermostat was 4 o'clock or the stove would fall into the inactive range, and at that level the room was 80 degrees (granted, it was shoulder season). Now I turn it down closer to 6 o'clock, the room is a comfortable 72, and I've been reloading every 20 hours. I'm really glad I stumbled upon this post and figured out what was going on. Thank you again.
 
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So, having both a Condar one and a BK one, I did a test today (first fire lit last night...).

I ran with the BK and swapped for the Condar (assuming 5 seconds of air sucking in the hole - I could not hear that, though - was not that bad...?).
Pics. Of course this is after 20 minutes to give the Condar time to get up to temp. BK 7.33 AM, Condar 7.50 AM.
The Condar did not change in the 15 minutes after I took the pic.

My conclusion is that the "active range" is different for the two.
My BK calibration is proper (at room temp indicator is near the little tickmark slightly below the "inactive" bar - as bkvp mentioned in this or another thread recently)

I did this test because I was running with the Condar in my small "test fire" a couple of weeks ago to make sure everything worked before I needed heat, and I thought the temp was low ("is my cat aging"?). But my BK, while certainly not high, was showing normal to slighty below what I remember from last year.
Load is mostly maple and oak, and this is last night's partial load, so it's near a small heap of coals.

I thought this was interesting to report.

View attachment 332314 View attachment 332316
Since boiling water is 212 degrees and an effective way to calibrate a thermometer, and the Condar probe has a 200-degree mark on it, why not dip the end of the probe in boiling water to get a reading.
 
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They are slow to respond, and filling the coil with water-saturated air at 212 F is not something I think is a great idea. Maybe it's robust enough but growing an oxide layer that's thicker on one side of the coil than on the other side due to the two different metals there would quite affect its calibration.

Good idea though. An oven is another possibility - if one trusts the thermometer in it

But even then, my suspicion is that the linearity of the scale differs between the two, i.e. the amount the tip moves for each 100 F increase is not the same. If so, one would need two points of calibration (boiling water and something at, say 600 F).
 
Not the white range, the outer white arc, like in the OP's thermometer.

View attachment 332328
Both my King and Princess were set at the red line from the factory. I reset the King to the tick mark to match what has been said and what is in the maintenance section of the manual. The dial is at 2 o'clock at reload which the manual says is way too hot to open the door. There are only a small bit of coals left, the firebox is about 200 F, and relighting takes an excessive amount of time.

I am currently starting a fire - thermometer has just hit the active zone so I opened the door and comfortably put my hand inside.
Something is inaccurate.
 
While your conclusion may be correct, the temperature in the firebox has little to do with the temperature measured after the cat.
 
While your conclusion may be correct, the temperature in the firebox has little to do with the temperature measured after the cat.
I agree with that in some circumstances. Starting a new fire and having the bypass open would suggest that the temperatures are approximately the same.
 
I'm not sure what you are saying (or how to conclude anything about room temp from the above pics).

This is the BK that has been on the hearth pad besides the stove all day since I took it out this morning (double wall convective stove sides, so not a lo t of radiation ; pad there is 84 F according my IR gun.)

The difference between the bottom of the inactive white range and the tickmark is negligible imo.
Didn’t somebody once claim that a BK meter was simply a rebadged condar meter? That appears to be false.

Perhaps all of the extra tick marks and arc lines on the bk meter are to be ignored. Maybe they’re just decorations.