IR Readings...where to aim?

[Stax]

After posting in the suggestion box and replying to the "Getting over 500" thread, I was communicating with a member via PM. Yesterday, I shot the coal bed of my hottest fire yet. That is where I got the reading of 740. Is this not the proper technique? My Rutland (placed on the top left part of box beneath my faceplate grills) was measuring 530.

If my IR reading is not the temp of my box, then I apologize to the forum member and please disregard my post in the suggestion box.

 

[begreen]

Use the IR gun to measure the hottest part of the stove, not the fire. If you pull the surround temporarily you can check the stove temp on top, a few inches in front of the flue collar. You'll have to shoot this reading at a sharp angle due to the convection duct surround. Now take another reading next to the Rutland. Note the difference. That will give you a relative sense of how hot the stove is getting on top, relative to your Rutland reading. So if you average say 550°F and the stove top is 650°, then just add 100° to the Rutland reading to know what the top reading will be once the surround is back in place.

PS: To avoid confusion, you might want to clarify your stove in your signature. It's a Lopi Declaration with an attractive Wilmington face plate.

 

[glenlloyd]

Most traditional thermometers cannot measure the way the IR does. Most traditional thermos are spring type with magnets. If you want to verify accuracy of your old style spring thermometer you should use the IR right next to it or around it.

I would say a reading of the coal bed is probably not a reliable measure. I sometimes shoot the fire through the door glass but I don't take that as gospel. I take readings from the cook top area, and I've had the thermometer on there reading 750+

Sounds like you need to let that thing fire!

steve

 

[Stax]

The problem with measuring the stove top is that Declaration has a shroud at the top for air to emit off the box. I'd say that gap is a good 2 inches between shroud and top of box. I would think measuring the shroud wouldn't be accurate, giving me lower temps. It is vertually impossible to measure stove top performance with this unit. I have taken readings next to the Rutland with the IR gun, ther're approximately 100 degrees lower.

As for my sig line: the actual name is Flush Wood Insert (noted on coverpage of manual), however, I will change it because it will probably be recognized easier. Good suggestion.

 

[maverick06]

Stax,
Thats exactly what I found, cant really measure the temperature. (I know I mentioned it to you in a PM, but figured I would here as well just for the record).

IR is nice, but no good spots to point it.... no place to stick the magnet thermometer. The best place probably to put it would be a few inches in front of the flue, way inside the grate. This would shield the thermometer from the air the blower is pushing, and get you probably the hottest temperature measurable.... But it would be very hard to get a thermometer there and nearly impossible to see it.

regarding your concerns with overfiring, hope it wasnt any advice I gave out! I have gotten mine so the tubes were glowing.... I dont like that, too hot, but as best as I can tell, glowing tubes is something people dont consider over firing. Thats still a very rare occurrence for me.

 

[jophysx]

When you use an IR therm. to shoot the temp of the fire throughout the glass, what you are getting is the temp. of the glass, not the fire or coals. You can prove this to yourself by aiming at the same point in the fire from different angles. The temp. will read different values because you will be hitting different points on the glass. Then do the opposite. Aim the gun at different points in the firebox, but keep the beam passing through the same point on the glass (by pivoting around a fixed point). The temp. will stay roughly constant. The bottom line is the reading you get depends on where the beam hits the glass, not what it's aiming at in the firebox.

 

[Stax]

Mav...love the first line of your sig!

 

[maverick06]

Mav...love the first line of your sig!

Thanks! Go ahead and use it too! I will just take creadit for using it first

 

[maple1]

I got an IR thermometer on sale earlier this year (Canadian Tire house brand) - just got around to popping it out of the package & trying it yesterday. It appears to be a POS. Try it right next to my magnetic one on the stove pipe, right on. Try it around different water pipes, it's all over the place - too hot to touch where it says 90°, and I can hold my hand on in places where it was saying 150°. Says 120° on side of furnace, and it's barely warm. Says my cold water in pipe is 80°, it's COLD. Get what you pay for, I guess - too bad I waited so long to try it, the receipt is long gone...

 

[Battenkiller]

After posting in the suggestion box and replying to the "Getting over 500" thread, I was communicating with a member via PM. Yesterday, I shot the coal bed of my hottest fire yet. That is where I got the reading of 740. Is this not the proper technique? My Rutland (placed on the top left part of box beneath my faceplate grills) was measuring 530.

If my IR reading is not the temp of my box, then I apologize to the forum member and please disregard my post in the suggestion box.

The IR gun only reads the temp of the actually surface it encounters first. If your coals are glowing at all, they are way above 740ºF since solid objects first begin to glow at about 900º. The coals are more likely up around 1200-1400º.

When you aim it at the coals it is actually measuring the surface temp of the glass in front of the coals. Personally, I think that's as good a spot to aim at as any. What you want is a reference temp to judge the heat inside, not an absolute temp of any particular area. 600º on the glass means the inside of the stove is a lot cooler than it is when it reads 740º. What else do you really need to know?

FYI the little red laser dot is only an aiming aid, and is not the same size as the actual sensing area. The sensing area surrounds the dot, and grows larger as you move farther from the surface you are measuring. You can't see that area, only the dot in the center of it. At 10', a gun with a D:S ratio of 6:1 it actually reading an area 20" across, with the tiny dot somewhere near the center. So, if you really want to measure an exact spot, you really have to get close.

 

[Stax]

Good to know BK, thanks.

 

[turbocruiser]

The problem with measuring the stove top is that Declaration has a shroud at the top for air to emit off the box. I'd say that gap is a good 2 inches between shroud and top of box. I would think measuring the shroud wouldn't be accurate, giving me lower temps. It is vertually impossible to measure stove top performance with this unit. I have taken readings next to the Rutland with the IR gun, ther're approximately 100 degrees lower.

As for my sig line: the actual name is Flush Wood Insert (noted on coverpage of manual), however, I will change it because it will probably be recognized easier. Good suggestion.

This is the same "problem" I have measuring my temps on the Regency where the top "stove top" is actually floating above the bottom fixed stove top. I use the thick connector collar as one measuring point and then use the IR thermometer to shoot the thin gap between the floating stove top and the fixed stove top for all my temperature measurements now. I regularly read 700-800 degrees F on those two areas and only around 400 to 500 on the floating top.

The other thing I wanted to write about all this is that one time my secondary tubes showed some signs of glowing. I immediately damped down the stove thinking it was way too hot. I later called Regency and asked about this and they told me that glowing tubes are no problem, repeat no problem, what I was told to watch for was if the tubes started sagging at all. The other thing that glows is the top "air wash wing" that helps to keep the glass clean. Regency also told me that was no prolem. Hope this helps.