Lennox and BIS Fireplace/Stoves - How to measure and monitor temperature/performance???

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Corners

New Member
Hearth Supporter
Oct 10, 2009
29
Gardner, KS
Hello all,

I have a Lennox Brentwood. For those that aren't familiar, it's this one: (broken link removed)

My question is, what's the best way to measure temperature to monitor performance in this unit? There's no heating surface, and everything on the unit is insulated and stays cool-ish, except for the trim on the cast iron door. Also, the chimney is double walled packed with insulation, so no drilling or installing a thermometer there.

If any of you have some ideas, I'd like to hear about it.

Thanks,
 
I have the BIS Ultima which I believe is the same as yours. Last year when we put it in I was wondering the same thing and ended up trying a magnetic chimney thermometer. If you remove the upper grill, above the door, you will see the short stubby flue pipe where your insulated pipe connects. I put mine on the stubby portion which is just single wall pipe below the flange. Ran a good fire or two to see where the temps were running, then I moved the temp gauge to the face of the fireplace. The door is arched across the top. There was enough room to put it on the upper left side of the door while still being in front of the firebox. I seem to run about a 150* difference between the two spots but I know if its reading 350* on the face its about 500* at the stack.

Thats what I do.

Or, get yourself an infrared thermometer and just point and shoot it at the fireplace for a reading.
 
I have the Brentwood and also get a similar 150F difference from front face above door to the stack. And actually, the top of the box can be hotter than the stack. All of this varies depending on whether the fire is getting or hotter, stable or dying.

From the manual:
The Brentwood fireplace will operate best if
attention is given to operating the unit with the
damper fully opened after refueling in order
to bring the firebox and the chimney system
up to their optimum operating temperature.
Combustion efficiency is relative to firebox
temperature. A temperature of 500º C (932º F)
and up, with a visible flame, in the upper part
of the firebox indicates a maximum efficiency.
To obtain this temperature, the fireplace must
be operated with the primary air and air boost
controls fully opened during 10 to 20 minutes
after reloading, depending on the heat and on
the moisture content of the wood.

Any thoughts on what the maximum temperature on one of the measurable surface should be (I have an IR thermometer) based on the owner's manual description above?

I have been limiting front face temps to 350F, stack to 500F and the top has hit maybe 575F.

Thanks,
Pete
 
I also have a BIS Ultima wood stove , and have wondered " ok how hot is it??" purchased a magnetic thermometer on the inside of the stove on the exposed pipe I get readings of 550-650 dont know if this a safe level of burn or should back it down. Called leonexx and waiting on a reply. The owners manual states 932 F seems kinda hot , any thing over 600 gets a little smell going
 
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