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mbreward
22-01-2011, 05:50 PM
Can you please let me know what thermometer you are using to measure superheat in a walk-in freezer.
I have been using a multi-meter with a type K thermister adaptor measuring pipe surface temperature but at –20ºC the multi-meter (fluke) does not seem to give stable readings.
I have looked into other electronic thermometers but they are all rated at an ambient of <0ºC. Infrared thermometers have the same problem.
Any suggestions would be appreciated

Mark

sedgy
22-01-2011, 06:23 PM
hi mbreward,
I have for a long time had a RS206 -3738 c+f , hold button, t1 and t2 plus plastic cover< which I put on the thermometer upsidedown to cover the readout screen.
happy testing, sedgy,

Tesla
23-01-2011, 12:18 AM
Hi mbreward
you could use a superheat calculation kit where the thermometer measures the direct temp of the refrigerant.
It is not a stable measurement - it is dynamic and due to the flow and constant adjusting of the metering device. The one is use is about 10 years old and it would be good if a manufacturer would build one that gives a K value with average, min and max readings. I use the yellow jacket ritchie.
I spoke with a boss from CPS in the USA last year and he said they were working on an electronic diagnosis tool which also did data logging.
0°C is a standard calibration temp I think the next standard is around 28°C (mercury) so 0°C is the closest for calibration for measuring superheat. I also have a fluke with a high digit resolution but have found they are not accurate and the range is too high.

mbreward
23-01-2011, 12:10 PM
Thanks Sedgy

Can you tell me what probes you use

stufus
23-01-2011, 12:32 PM
Hey Lads
I was constantly having trouble with readings from various manufacturers thermometers and found i was wasting money constantly buying new ones (although i now possess quite the collection)
In the end i bit the bullet and bought a yellow jacket system analyser.Real time superheat and subcooling graphable readings
and Monitoring capabilities all downloadable for client presentation.
A bit pricey but in my opinion well worth it .Has paid for itself over and over in time saved.
The only thing i did was replace the k-type leads with 2 clamp on probes from my combustion test kit.
It cost E800 and software upgrades are free from the Yellow Jacket site after registration(which is free)
Cheers
Stu
http://www.yellowjacket.com/node/928

Tesla
23-01-2011, 01:02 PM
stufus
Wow that is really cool and just what I have been looking forward to, thank you and of course I had faith in Yellow Jacket all these years. Just to be sure are there any other members that have a better product that we should know about before we spend the money?
Stu (Tesla)

sedgy
23-01-2011, 01:05 PM
hi mbreward, yes I used 2x binda pointed sensors. Velcro held sensors, handheld surface sensor and a couple of 5 meter cable sensors< with bare wire ends< hope this helps
sedgy

mbreward
25-01-2011, 06:20 PM
Thanks for your suggestions, I'll look into both of them, the Yellow jacket superheat testing kit looks very good & reading the refrigerant temperature must be better than the pipe surface temperature

thanks again


Mark

stufus
25-01-2011, 07:29 PM
Thanks for your suggestions, I'll look into both of them, the Yellow jacket superheat testing kit looks very good & reading the refrigerant temperature must be better than the pipe surface temperature

thanks again


Mark

Have a look at the Testo Manifold range seem to be popular with some members.Only used them once so not to familiar with them but do remember saying "when i earn a decent wage i'll invest in one of these"
But alas went on the piss instead:D
Cheers
Stu

Josip
25-01-2011, 11:59 PM
Hi,

I was using Testo 560-2 Refrigeration System Analyzer (for ammonia and other 30-40 max refrigerants ) good instrument .... can be connected to PC to store data etc...etc... quite expensive was that one about 2500E+ ... of course with wire and radio temp probes, SS flexible hoses...

Best regards, Josip :)