They don't work as well as they claim in the field.
Neither type work in all scenarios and on all line sizes, which is why we need multiple options, including bare probe sensors removed from clamps.
Eventually, the sensor wires on the FP probe failed and it landed on the junk heap of failed sensors with other Fluke clamps, bead probes, insertion probes and meter leads.
The FP clamp is much worse than you know if you are calling it alright. More times than not they are double digits off for me. The TC material is quality but in the clamp it stinks.
The TC wires are soldered to the back of the metal plate in the jaw, which is in solid contact with the plastic jaws, which also have slots in them that allow relatively free movement of ambient air in contact with the plate.
For the money, they are not bad probes, people just need to be aware that under many of the conditions we face on nearly every call, they need to be insulated.
The same is true, to one degree or another, for every brand of probes.
The best all around "real world" performing pipe probes that I've used are the PT100 pipe wrap probe that came with the original 1st generation Testo 523, the Cooper 4011 pipe wrap, and the Fluke 80PK-8 and -10 pipe clamps.
I haven't tried the pipe wrap probe for the newer Testo manifolds, or the Cooper NTC thermistor pipe clamp, so can't speak to the performance of them.
Wraps tend to be more precise than clamps, but clamps are just so damn convenient. :o
They sell the Cooper for the same price as the Fieldpeice
So for the money they are not that great IMO
Oh and yet another reason to be on a first name basis with your postman
testo is now extending warranty out to 3 years with a mail in rebate
I like my ak900 so much I bought a 2nd one. The sensors it ships with are crap and immediately went in the trash. I have the clamps I did the mod on and a couple stretchy sensors I was given. I've used the sman3. Didn't hate it but wasn't used to it and felt like it was missing something. I talked an old timer into a drsa. He went with a dc, ak900. Few years back a friend bought a testo. This was before I've ever seen a drsa in person and he only had it a few days when the hook broke and the pins in the sensor plug broke. I believe it's sitting in a landfill now.
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#1. This was a good many years ago. While similar, my clamp was an older model than what is being sold today.
#2. I did no serious accuracy testing with it. It was well before I started thinking about things like ambient temperature influence and accuracy and repeatability.
#3. It was mostly used to measure superheat in refrigerated cases where the ambient temp around the sensor is only a few degrees warmer than the sensor itself.
Perhaps those things influence my perception of it as "alright"
Wow, a lot of good information. I'm pretty sold on the ak900. Do any vendors like R E Michael's sell them? If Im going to buy them now I will have to get a loan from my company. If not, Ill just start saving.
Just saw from the link that they sell these translucent replacement rubber boots for DC DRSA's now too. Cool :)
For what I understand, you can order the AK900 from Johnstone supply but they don't keep them in stock.