Pid, mash thermometer and my hand held thermometer all read different temps

[Tonypr24]

I need some help figuring out my temp issue. I just got a new setup with a new mash tun, rims tube and pid controller. I did a leak run test and noticed my temps were all off..i set my pid to 120 degrees, my mash temp was reading 112 and my other thermometer i put in the mash holding it by hand was 107 degrees. I think my hand held thermometer is the most accurate as i put it in ice water and it read 32 degrees so i know its calibrated. My mash thermometer doesn't go that low so i couldn't do the same with it. Why are these so far off?
Since i kow my handheld thermometer is calibrated i tried to calibrate my mash thermometer by puting both my hand held and and my mash thermometer in 100 degree water but i couldn't calibrate it..it was off by 5 degrees, i tried using the lugnut on the back but it wasn't moving the hand on the thermometer no matter which way turned it.

Anybody know how to calibrate a Dial Thermometer - 3" face, 4" Probe, 1/2" NP from brewharware.com?

 

[BrunDog]

I think there is a screw on the back of the dial thermo for calibrating, though dial thermos will never be dead nuts accurate. If you have a thermapen they are usually on the money. Calibrate your handheld with both freezing and boiling water (need to know your boil temp at your altitude). PID probably has a calibration or offset.

 

[Tonypr24]

Brundog
I tried using the screw in the back of my dial thermo but i don't know if im doing it right. Am i supposed to see the dial thermo's arm move as i turn the screw on the back? I dont see the arm moving as i turn it.

 

[BrunDog]

Yes it should move slightly.

 

[CadiBrewer]

Brundog
I tried using the screw in the back of my dial thermo but i don't know if im doing it right. Am i supposed to see the dial thermo's arm move as i turn the screw on the back? I dont see the arm moving as i turn it.

On my three, the arm doesn't move, the dial rotates around the arm.

 

[Tonypr24]

I got my dial thermo replace and I was able to calibrate it along with my handheld thermometer and my auber pid 2362. I also auto tune my pid 2 times. All read 32 degrees in a bucket of iced water.
Now I have a new issue..when i set my target temp of 154 on my pid the dial thermo in my mash tun shows 144 degrees and my handheld thermometer ahows 149...how is this possible? Then i put all 3 back in the iced bucket full of water and they all read 32 degrees again. How are the temps so different in the mash tun. I have a Rubbermaid 10gl cooler.
Any suggestions?

 

[acidrain]

Different areas will read different values. That's normal. That's why circulation/stirring is so important.

 

[-CHRIS-]

If you have a thermapen they are usually on the money. Calibrate your handheld with both freezing and boiling water (need to know your boil temp at your altitude). PID probably has a calibration or offset.

RTD probes are notoriously non-linear so calibrating far from the desired measuring range e.g. 140-170 degrees F is not too useful. A better choice is to buy an accurate thermometer and test in the range that you will be brewing like you suggest with the thermopen.

The Thermapen is probably the most accurate relatively inexpensive probe on the market with +_ 0.7 degrees F accuracy. I suggest buying one of these and calibrating everything to it, that is what I do with my eHERMS system.

On brewday, I fill my HLT and circulate water through my MLT and verify the MLT and HLT probes with my Thermapen before starting the brew.

Chris

 

[TexasWine]

Any suggestions?

Calibrate everything to a Thermapen in the desired mashing temp range (140-170F).

Edit: ^ what he said

 

[Tonypr24]

Thanks guys i will look into a thermopen

 

[augiedoggy]

On my three, the arm doesn't move, the dial rotates around the arm.

Same concept.. The temp reading can be adjusted... Mine are the same way.