Thermometer Mod


 
Bob Mann

Bob Mann

TVWBB Honor Circle
After much reading, and a couple of posts, I decided to go with inexpensive units.
I got 2 - F&C, 2" thermometers, with 3" stems, off of eBay, both delivered for $20.58. The units come with a wing nut for mounting.

The required hole is larger then the 1/4" claimed. I marked the holes with blue tape, drilled a 1/4" pilot hole, then a slightly larger hole and reamed it a bit until the stem fit tightly.

I tested them in boiling water when I got them, and they are accurate. I haven't tested them on a cook yet.

They do look good. :)

On my 22 1/2" WSM.
thermometer03.jpg


On my 18 1/2" WSM.
thermometer02.jpg


The pair.
thermometer01.jpg


Close up.
thermometer04.jpg


Side view.
thermometer05.jpg


Inside, through top grate.
thermometer06.jpg


Inside, no top grate.
thermometer07.jpg


Bob
 
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I like it. Probably will do this since I've removed the ones in the lid and installed an additional vent in the place of the lid thermometer.
 
Those look good. Now , did you install them because you felt that the factory therms were inaccurate , or were you looking for grate temp vs dome temp?
 
WSM dome thermometers are accurate, but their placement in the lid does not reflect the actual cooking temperate at the grate. In my WSMs, the lid thermometer typically reads 50F lower than a thermometer at the grate level.

I was using a Maverick ET-732, then I started using a Weber 9815 analog thermometer inserted in my side, probe grommet. Both work really good, but I want something permanent, that I didn't have to play with on every cook.
 
"Both work really good, but I want something permanent, that I didn't have to play with on every cook. "

Bob, this makes me want to look at this mod more closely. Thanks!
 
I see, it's like the SJJ mod with the gauge in the ring side, sha wheat. For some reason I couldn't see the pics yesterday when I was logged in.
 
I have a question on this mod though...Since the thermometers have such a short stem it made me wonder something. Wouldn't they in fact pick up the heat waves from the charcoal that rises up along the sides around the water pan edges more so than the actual temp of the unit via the center of the grate? Heat would rise up around the edges since the pan is there and then rise to the top and swirl down in a way but at a slightly reduced temp at the centers of the grates...
I may be over thinking this but just curious since it places the stem closer to the charcoal heat rise area....

Bob Mann
Nice selection of Webers there.
 
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Mike Leiter said:
Since the thermometers have such a short stem it made me wonder something. Wouldn't they in fact pic up the heat waves from the charcoal that rises up along the sides around the water pan edges more so than the actual temp of the unit via the center of the grate?
Click to expand...
Maybe, that is part of the reason I didn't buy more expensive thermometers.
I was also concerned that a longer stem would get in the way of food on the bottom grate.
If these don't work out, I am probably going to drill out the holes and install grommets like I did for my probes. I will then keep using my Weber 9815 analog thermometer, which has a 5" stem, is removable, and I know works well.

Mike Leiter said:
Bob Mann
Nice selection of Webers there.
Click to expand...
Thank you!

Bob
 
Bob Mann said:
Maybe, that is part of the reason I didn't buy more expensive thermometers.
I was also concerned that a longer stem would get in the way of food on the bottom grate.
If these don't work out, I am probably going to drill out the holes and install grommets like I did for my probes. I will then keep using my Weber 9815 analog thermometer, which has a 5" stem, is removable, and I know works well.

Thank you!


Bob
Click to expand...


Like I said I was just curious...It really seems like a great mod to get temp readings from all over the WSM and I thought about it also after seeing your pictures. It just made me think that it would read more of a heat wave up the side temp than the cook surface temp. I know the dome thermometer is pretty far off from the grate temp and was curious if this would read the same or closer to the 1st grate temp. I can see how a longer stem would make the grate hard to get out without dumping your food..LOL I really would like to see how this reads on one of your cooks comparing this reading to a grate reading at that level. If its close it looks like I`m drilling another hole as I like the quick visual it gives.
I do have the grommet mod on mine already and that leaves me with having to choose upper or lower grate temp and or food temp or having to buy more remote units if I want to measure temp in multiple places..
 
Mike Leiter said:
I do have the grommet mod on mine already and that leaves me with having to choose upper or lower grate temp and or food temp or having to buy more remote units if I want to measure temp in multiple places..
Click to expand...
I generally just stick my pit probe through the grommet, and let it hang. It goes in far enough, where I feel I'm getting a good grate reading, but winds up being between the top and bottom grates, which should give a good indication of the overall grate temperature.

Bob
 
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I finally did a couple of cooks since I did the thermometer mod to my WSMs.
The added thermometer reads from 5-25F degrees higher than a thermometer at the grate. The readings seem to get higher the longer the cook goes on.
It works pretty good, much better than the dome thermometer, which always read 40-50F lower.
I'm happy with the results.

Cook #1 CyberQ pit probe reading.
thermometer0201.jpg


Cook #1 modded thermometer reading #1.
thermometer0205.jpg


Cook #1 modded thermometer reading #2.
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Cook #1 dome thermometer reading.
thermometer0203.jpg


Cook #2 CyberQ pit probe reading.
thermometer0301.jpg


Cook #2 modded thermometer reading #1.
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Cook #2 modded thermometer reading #2.
thermometer0305.jpg


Cook #2 dome thermometer reading.
thermometer0302.jpg


Location of CyberQ pit probe.
thermometer0205.jpg


Bob
 
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Bob - did this mod and have not been able to figure out the temp reading on new mod thermometer vs. the dome and the 2 oven thermometers(placed on top grate) used to test temp. When the dome thermometer reads say 250, and the 2 oven thermometers read 265-275 the new mod thermometer was 320. I took it off and boil tested 3 times - 1st it was 185, 2nd test 210, 3rd 185. I'm thinking I need a new mod thermometer and was wondering which size and brand would be the best unless other ideas come to mind. I'm not really concerned about price if it will be accurate and dependable. BTW your reply on a post recently about closing 2 vents and controlling air flow with the 3rd has been a game changer for me in temp control. Thanks!!
 
Glad to help Danny.
The inexpensive, 2" Chinese made thermometers I used in my mod seem to work fine, in the short term anyway.

Bob
 
There is another option using Bob's idea with the thermomter below the cooking grate. Buy a candy style thermometer with the long stem, 12 " and use a BBQ Guru grommet. The hole is just slightly larger than the stem. Then all you have to do is slide the thermometer in during the cook and pull it back so it does not get in the way of anything. It will take the point of the thermometer mid way into 22. When you are not using it the hole is so small that it will not infere or just plug it with a little piece of foil. When I had my 22 WSM I used my turkey fryer thermometer and it worked just fine.
 
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Gary S said:
There is another option using Bob's idea with the thermomter below the cooking grate. Buy a candy style thermometer with the long stem, 12 " and use a BBQ Guru grommet. The hole is just slightly larger than the stem. Then all you have to do is slide the thermometer in during the cook and pull it back so it does not get in the way of anything. It will take the point of the thermometer mid way into 22. When you are not using it the hole is so small that it will not infere or just plug it with a little piece of foil. When I had my 22 WSM I used my turkey fryer thermometer and it would just fine.
Click to expand...
I like this suggestion. Thanks very much.

I googled "bbq guru grommets" and didn't get a direct link to purchase grommets. I did go on bbq guru's site and put in grommets in search bar and had no responses. I did however find grommets on cajun bandit's site. My question is: if the hole for the temp mod is slightly larger than 1/4" what size grommet should I order? Thanks
 
Very nice mod, Bob.
Did a somewhat similar mod last year after taking Harry's class. Noticed he placed his Stoker pit probe thru a grommet
just below the top grate. The probe tip was maybe 2" inside the cooker. My first cook was with the pit probe in the clip
on the grate. All since have been thru the grommet and have worked extremely well. The Stoker is able to respond faster
and more accurately to even small temperature changes, that is unless a (larger than needed) chunk of wood takes alight...

Bob
 
Great idea, something I plan on doing myself. One question - why not install another thermometer for the bottom cooking grate? Does it not get used enough to justify drilling another hole? Was actually thinking about doing one for both grates.

Dan
 
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