Fluke 52-2 Dual probe thermometer

[killermiller]

I got mine today. The local store I ordered it from special orders it and it took 3 weeks. I was pretty excited to put it up againts my UEI. The thermometer comes with 2 probes. I fill up my insulated coffee cup with crushed ice and cold water from the faucet. The Fluke with the Fluke probe and the both read 32f-32.1f. I was pretty happy. So I connected the Fluke probe the the UEi and it read 32.5. Still pretty excited since I didn't know the accuracy of the UEi. I also have some ebay probes that read 2f off, according to the Fluke.

EDIT - I just swapped the probes and the fluke read 32.5 too so I guess they both read the same temp.

[DetroitAC]

Congrats, but it is very typical for an in-spec thermocouple to be off by a few degrees. That's sort of the nature of the beast. Your Fluke lets you plug in an offset to compensate, and what we do at work for handheld probes is put a little label on them that tells you what the offset should be as well as cal date.

[killermiller]

So is the accuracy linear?

[mike8913]

wouldn't it be more accurate to freeze the probe in an ice cube tray and then make the reading? Maybe the difference would be negligible.

[killermiller]

Water begins to freeze at 32f but it also begins to melt at 32f. Ice can be colder then 32f. Combining the ice cubes the cold water bring it to a melting state.

[tim-]

biggest issue I've seen with uei (i have a fluke 52-II aswell but havn't use it much) is that the temp can change in some condition 5-6*c if i have 2 probes connected compare to one, that doesn't happend on fluke..

for example:
I have 2 probes, one on evap and one on loadtester. Normally I want to see both temps at same time since I charge, sometimes lowest evaptemp isn't lowest loadblock temp. well when I have both pluggen in I can have for example -26*c/-18*c (evap/loadblock) when disconnecting loadblock I have about -32*c, the same symptom with loadblock temp. I've test over 20K-probes in case it was some damaged probes but no, it's the same with all brand as well as K and T.

fluke is the way to go :up:

[DetroitAC]

So is the accuracy linear?
Unfortunately it is not always linear. The errors are created by minute differences in the alloy compositions, and you never know which metals are too much, which are too little, etc. A big wire mfg. like Omega will test a spool of wire to be within their tolerances before they sell it to you (4F or 2.2C). Wire of unknown origin (ebay) you probably don't know how accurate the wire is. The best thing to do is check the calibration at a temperature close to the temperature you'll be measuring. That is a hard thing to do at home, so you really just have to do the best you can with reasonable effort. Use the ebay TCs, just check them first you know what you're dealing with.

TC wire is always off by some amount since the wire that is closest to the standard is held aside for "special limits of error wire" that is more expensive than standard wire. I have no idea what Fluke supplies with the meter, maybe it's pretty good stuff.


wouldn't it be more accurate to freeze the probe in an ice cube tray and then make the reading? Maybe the difference would be negligible.
No, that would give you subcooled ice, you would have no idea what the ice's temperature is, it could be as cold as the freezer. Calibrate in an ice bath, with mostly crushed ice and very little water. This way you know that the ice/water is at the saturation point (Yes, it's just like a refrigerant saturation point). For best accuracy stir the heck out of the bath with the probe so there is good heat transfer, and the probe isn't touching a side wall or embedding itself in an ice chunk.

[teyber]

congrats!

i got my uei dt200 yesterday im pretty darn excited!

Fluke is a darn good thermometer. What model UEI did you have?

[killermiller]

I have the DT150 and was getting tired of switching the probes so much. I almost got a DT200 but I heard some questioning the accuracy of the DT200 using both probes. I could have gotten 2 for the price I paid for this. Although I bought is locally for cheaper then anyplace I could find online. I wanted something I didn't have to hope was accurate. I like the dual probe, I can check SH and SC or discharge and SC or evap and SH. Its great.

[Marvin]

The Fluke is the most reliable meter. But i love my UEI that reads the same temps on both probes.

[jinu117]

Marvin... try this... put one thermocouple to say -60c, the other to ambient. Now pull one of them out. See how it just easily moved anywhere from 3-10c? This is the problem with UEI DT200. I've seen one that only moved 1-2c which progressively got worse eventually... -_- (out of 7 i think total)

[teyber]

Marvin... try this... put one thermocouple to say -60c, the other to ambient. Now pull one of them out. See how it just easily moved anywhere from 3-10c? This is the problem with UEI DT200. I've seen one that only moved 1-2c which progressively got worse eventually... -_- (out of 7 i think total)

your scarin me jin! Is the problem only with 2 k-type's in at same time?

[Marvin]

Marvin... try this... put one thermocouple to say -60c, the other to ambient. Now pull one of them out. See how it just easily moved anywhere from 3-10c? This is the problem with UEI DT200. I've seen one that only moved 1-2c which progressively got worse eventually... -_- (out of 7 i think total)

You are correct. Fluke is a lot better, but i am a luck guy. My meter didnt that. If i have a money left i would buy a fluke 54.

[tim-]

teyber:
yes it is.

[killermiller]

I thought long and hard about getting a fluke. I think I made the right choice. I thing the UEI is a nice starter thermometer.

[jinu117]

Well, I don't mean to scare anyone... it's just... when you have hand on 7 and eventually all of them start reading out of land temps... and you use only one probe to compensate for that... and than... out of 2 I had toward end died and had to RMA.... it's bit iffy to say the least.
Keep your retail receipt well.

[killermiller]

Jin scared me into the Fluke. He must be some sort of spokesperson :D

[jinu117]

No... just honest attempt to save you guys money.... I've burnt enough money on UEI as you can see... (and some of my early customer buying ones through me... -_-)

[teyber]

No... just honest attempt to save you guys money.... I've burnt enough money on UEI as you can see... (and some of my early customer buying ones through me... -_-)
Alright:up: If mine breaks, ill RMA it and then sell it new and buy a fluke. But i think for a first time builder, a thermometer is a luxury.

And killermiller did you get the fluke 52- dual input with data logging or without logging?

[killermiller]

How many flukes have you been through? 52-2 is dual input with out logging. The 53-2 and 54-2 have data logging.

[dinos22]

my Fluke 52 old school one is awesome
and both probes read the same temps

:) great TM

[jinu117]

How many I went through? 1 and still going strong since day one of doing this... :) I really need to get more but fluke doesn't seem to make more than 2 probe model that is easy to move around... -_-;

[teyber]

why do you deal with so many thermo's jin? I know you have a buisness now, but when you said "when you started with 7 uei's" why so many lol?

[jinu117]

Actually cascade needs at least 2 to do properly if not 3.
Single stage need at least 2 to do proper diagnostic to be honest.
As you can see numbers ramps up quite fast if you start logging all data involved. Something like auto-c with simple 2 stage would need at least 6 to properly diagnose.
I actually started with only 2. 2 UEI DT200.
Within a month of it, I got Fluke 52-2
And than some customer wanted UEI from me so I grabbed about 3 more for them. Out of these 3 2 went through RMA.
By now, I am disenchanted with UEI already and one of 2 I had to RMA.
Than I just sell the RMA'd one.
And than I went to grab some new one that did data logging (still using it too this one has been good... read temp 1-2c off with large diff in between but nothing like UEIs).
Recently (well 2 months ago, the other UEI bites dust and RMA'd... sold it)
So probably more than 7 UEI through the course and majority of them going bad over time. This doesn't include ones I personally saw bad at Chilly1's place (about 3-4?)
Right now, I have Fluke, the data logging one, Fluke Infrared with 1 port, 1 Fieldpiece multi clamp meter with another 1 port. Barely enough to get going for me. Hence looking for meter that won't take these when I need to work on big projects... (min 4 port more like 8 ports)

[teyber]

Gotcha. I thought you ordered 7 thermometers and i couldn't make sense of it!

so which is the new data logging one? is it a new version of the uei? At least its got a 3 year warrenty...

But miller, congrats on the sick sick sick thermo!

[jinu117]

New? Nah it's old... BK Precision is the one I use. Also called many diff name.