Thermometer installs and calibration

[bencops]

After 6 months of working up the courage, a pair of tel-trus in the WSM (pre-2008 they didn't have inbuilt thermometers) and one touch platinum.

I had to drill a 22mm hole in the lids - I used a step drill bit http://www.amazon.co.uk/gp/product/B0015NPPCY/ref=oss_product to drill the hole. I masked off the area to "prevent chipping" for the first one but that didn't make any difference. Dripping WD40 onto the drill while drilling was what worked to create a clean hole. I touched up the area after with high temperature paint so it won't rust.

I checked all my thermometers against boiling water just to see - should be 212F

- Maverick ET-72 (mark 1): 212 (both probes)
- Thermapen: 211.5
- Both tel-trus: Exactly 220F

So the new thermometers are out by the same amount - 8F. They're not re-calibratable so I'll just have to compensate. They look nice though.

Photos:
Drilled holes

IMG_0451 by Copsey, on Flickr

IMG_0450 by Copsey, on Flickr

IMG_0448 by Copsey, on Flickr

Installed thermomters

IMG_0452 by Copsey, on Flickr

IMG_0454 by Copsey, on Flickr

IMG_0453 by Copsey, on Flickr

[Vic.]

Do you only need to calibrate thermometors on the WSM's or do all thermometors need calibrated. I bought one from rivercounty, USA (thanks Al for the advice, good solid piece of kit) and it seems to be fine.No instruction to calibrate it. What does the calibration process contain?

[Swindon_Ed]

Vic, prettey much all non digital thermometers will be out by a little bit. Ben's ones being 8f out is really good as the one's in both my WSM and ProQ are out by about 30f.

To calibrate a thermometer you boil a pan of water and place the probe in. if the thermometer is right it will read 212f if it's not and you're able to recalibrate set it back at 212f or 100c.

[Vic.]

To calibrate a thermometer you boil a pan of water and place the probe in. if the thermometer is right it will read 212f if it's not and you're able to recalibrate set it back at 212f or 100c.

Don't think i'm able to recalibrate mine, its all sealed up. Just read up on it and its factory calibrated. Will check it with the boiling water method just to see what it reads.....thanks Ed

[Vic.]

took mine off, measured the temps and it was between 220-225f for boiling water. That's not bad. Now I know to keep my smoker at the lower end ...cheers Ed....and cheers Al, that's a good factory calibrated thermometor

[Vic.]

Hi Ben, You made a good job drilling that enamel with a step drill bit. Never used one of those on enamel myself. They're expensive pieces of kit......that must be strong bonded enamel on the WSM's

[Steve]

Bi-metal thermometers are never as accurate as the digital ones. They also have a tendency to break down and stick. Tel Tru's are the rolls-royce of Bi-metal BBQ thermometers, I concur with Ed about how good Ben's are being so close. I've got a Tel Tru waiting to be installed in the lid of one of my WSM's, the stock thermometer is well off

I tend to use the Maverick as my proper monitor at the moment as it's about the best remote probe for measuring pit temperature that's available at a reasonable price for now.

Just need someone to drop a reasonably priced thermocouple based remote pit probe onto the market

Good job on the install by the way Ben.

[Vic.]

I'm happy with my 8-13f difference, couldn't ask for a better product. Although it came from the US it cost more, but at least you were there to offer help Al....thanks

[Steve]

8-13F off is nothing Vic, I recon you're quite right to be happy with it. You know it could even have been bang on when you first got it but the nature of bi-metal thermo technology means they lose accuracy when used, particularly in a smoky environment.

If you want something dead on and that will stay dead on, you want a thermocouple that's been properly calibrated, these come with certificates of calibration. Would I be over bothered for a pit probe, nah. For a food probe yeah definitely, that's why I always use a Thermapen over the Maverick because it is always bang on.

[Steve]

I'm not offended Al but it's not as black and White as your statement suggests.

Any thermocouple needs it's cold reference setting which is how they are calibrated. Just as any thermometer needs to be calibrated at time of manufacture whether it's thermocouple, thermistor, bi metal etc. Thermocouples also can lose accuracy over time so recalibration may be necessary, from day one they are more accurate and responsive than both bi-metals and thermistors, they're just a much better technology.

Out of the factory in the UK, Thermapens are tested, calibrated and certified so they are all dead on unless there's a fault that has been missed in quality control (but that won't happen often - I've been to the factory and everything is done properly).

For health and safety regulatory reasons they may need to be tested and calibrated during their lifespan to ensure they are still correct. Remember these things are used in safety critical industries so they need to be accurate, kept accurate and for proof of that to be documented. The thermocouple in a Thermapen is actually the same as used many other industrial thermometers made by ETI.

So as with any thermometer you should test it regularly to check it's still dead on and recalibrate if it's not. I would also send mine into ETI if they ever needed recalibrating as they get it accurate to 0.1 of a degree, much more accurate than DIY calibration. So a properly maintained and tested Thermapen will always be deadly accurate.