Goofy Temps


 
J

JimT

TVWBB Pro
I'm about an hour into an all nighter, and thought I'd see if anyone had any thoughts on my temperature dilema. On my last cook, I noticed some odd readings, so this time I loaded the WSM with all kinds of thermometers. I have an Omega thermocouple between the top and bottom grates, an ET-73 clipped to the top grate, an Ashcroft thermometer lid mounted, and two Nu-Temp probes stuck through the top vent.

At my last check:

between grates = 200
top grate = 221

OK so far, but....

Ashcroft in lid = 180
Nu-Temp 1 in lid = 189
Nu-Temp 2 in lid = 217

I pulled the thermocouple out an stuck it down through the top vent. Low and behold, the temp readings were pretty close to what I was seeing on the Ascroft and Nu-Temps. All over the map, depending on where I held it, but always colder than I was reading at the grates!

I haven't calibrated any of them recently, but at room/outdoor temperature they all seem very close.

Any thoughts?

JimT
 
Jim,

Good Morning!

The temps of the Aschcroft and the 2 Nu temps; My guess would be that the 217 reading perhaps that probe was closer to the inner surface of the lid as opposed to the middle of the lid space, if you catch my drift.

How did you light the WSM? Minion Method or Standard? How many coals did you use with Minion? It's cold here tonight, maybe the outside air temp has something to do with the lid temps being lower than the grate.

What are you cooking? If you have a big load in there sometime s that can effect your temps.

I wouldn't worry too much, give it a little time and see how it goes. It will probably take at least an hour for the cooker to get up to cooking temps anyway. Don't over think it.

In the mean time boil a pot of water and check the therms and see if you get 210-212. Then you'll feel better.
 
And Good Morning to you, Bruce!

I was awakened at 4:00 AM by the low temp alarm on the Maverick. Tapped some ash off the coals and opened the bottom vents to 100% (they had been about 50%.) Temps are climbing as I write.

I tested both Nu-Temps and the thermocouple in boiling water. They all were right on the money.

There are two butts on the top, a brisket on the bottom. Total weight around 21 pounds. My plan is to put the Nu-Temps in the butts in a few more hours. Maybe I'll pull the Maverick at that point for a calibration check.

Yawn,

JimT
 
Oh, I forgot.

Minion method start up. Charcoal ring almost overflowing, smoke wood mixed in, 30 coals to light.

JimT
 
I was getting some odd temp readings last year and contacted Guru. They replied that the best way to check temps is to tie or wire the 2 probes together because the convection causes different readings even inches apart.

Rita
 
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Rita Y:
I was getting some odd temp readings last year and contacted Guru. They replied that the best way to check temps is to tie or wire the 2 probes together because the convection causes different readings even inches apart.

Rita </div></BLOCKQUOTE>

I can definately attest to that Rita.

At one point in this cook I had three probes placed in different positions through the top vent, in addition to the mounted thermometer. The temps varied dramatically.

What I discovered (loooong story here, cut short) was that I spilled water on the charcoal when filling the water bowl. Only one side of the chamber was hot, causing these strange convection currents and temperature readings.

Another lesson learned,

JimT
 
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