Sestos PID Versus Rex C100 PIDS

[BenB]

for a brewmachine build the extra £5-£10 spent on a quality probe that reads true has to be worth it imho check out these folk
https://www.sensorshop24.de/

How many sensors!!! Can't find any 3 wire PT100s though which is bizarre! They only seem to sell 2 wire sensors.

[Fil]

for a brewmachine build the extra £5-£10 spent on a quality probe that reads true has to be worth it imho check out these folk
https://www.sensorshop24.de/

How many sensors!!! Can't find any 3 wire PT100s though which is bizarre! They only seem to sell 2 wire sensors.

after you select the probe type pt100/pt1000/ntc etc the next drop down box is populated with lead length options, and once thats selected you can then select the wire config 2x 3x 4x etc...
http://www.sensorshop24.de/temperaturfu ... d/a-11175/

[BenB]

Oh really- cool! I wondered what "Schaltungsart 3 leiter" meant. Google translate turned it into "Switching 3 conductor" and the description still described two wires even when 3 wires were selected. But it does kind of makes sense- there are options of 2, 3 and 4 which is kind of traditional wiring configurations for PT100s.....

All because Ich spreche kein Deutsch.......

[Buster]

Nice site that Fil, Germans always make good quality stuff. I did wonder if the ones on Homebrewbuilder's site (Mr Lard) were ok.

[Fil]

@Buster, i would buy from MrLard with confidence any probs and he will replace or refund without question..

@BenB chrome/google translate kicks in on my browser within few seconds of loading a DE page so all the drop downs etc are in 'me-speak' ich nicht sprecon de deutch

[BenB]

Just as an update- I'm getting ready for a brew today so had a chance to check the calibration compared to my Thermapen. At 20 degrees the Sesto/Chinese PT100 combination is off by 0.5degC. At 65.0 (which is what I calibrated at) it reads exactly the same. Admittedly on the sensor there is a little bit of rust between the shaft and the threaded section but nothing I can't live with for the moment.
It looks like they've got some quality control issues- this isn't a surprise. But I'm still surprised they were giving such bizarre readings for you Buster. Unless the rusty section on those sensors isn't sealing and water is getting into the sensor and shorting it out?? The whole thing with these sensors is that they're relatively simple...

[Buster]

Just as an update- I'm getting ready for a brew today so had a chance to check the calibration compared to my Thermapen. At 20 degrees the Sesto/Chinese PT100 combination is off by 0.5degC. At 65.0 (which is what I calibrated at) it reads exactly the same. Admittedly on the sensor there is a little bit of rust between the shaft and the threaded section but nothing I can't live with for the moment.
It looks like they've got some quality control issues- this isn't a surprise. But I'm still surprised they were giving such bizarre readings for you Buster. Unless the rusty section on those sensors isn't sealing and water is getting into the sensor and shorting it out?? The whole thing with these sensors is that they're relatively simple...

So far I have tried 3 of those PT100's from that Ebay Site and they all give a different reading on the same PID, so I think I am right in saying its the cheap PT100's that are to blame for the wrong temp readings. I am waiting for a new PT100 from Angelhomebrew which was approx £18.00 delivered. When it arrives I will update.

[Fil]

imho its the probes the ebay china bargain basement priced probes are a punt.. and not a very good one, while i have a couple of the £2.50 pt100's that do read true i have had more that read way wide than read true.. iirc from 2 x purchases i have bought 5 x far east ebay probes to end up with 2 x reliable ones..

[Buster]

imho its the probes the ebay china bargain basement priced probes are a punt.. and not a very good one, while i have a couple of the £2.50 pt100's that do read true i have had more that read way wide than read true.. iirc from 2 x purchases i have bought 5 x far east ebay probes to end up with 2 x reliable ones..

+ 1 on that Fil, I am thinking that once I have calibrated the cheap ones to 70'c , I only need 10'c either side for what I need them for, maybe that will suffice but as I said earlier, I have ordered a PT100 1/4 BSP from Angelhomebrew only for the fact that he included the nut and washer seal kit in with the price for £18.00 delivered where as Mr Lard wanted extra for the nut and seal kit. I shall keep the thread updated.

UPDATE *** After I tested the Chinese probes in water 2 days ago I dried them and put them back in their plastic bags, took them out today and they are RUSTY !!!!!

[VANDEEN]

Yep Buster, the lads at work refer to the "three common grades of stainless" 316, 304 & Chinese LOL

[Buster]

Aha! Sorry- my mistake. I cured this with ebay 191436133569 but using a sesto. Depends if the rex can get into the hidden menus to do a pt100.

Cheers BenB, just ordered 2.
I have a Sestos-V and a Rex C100-V

I just noticed after buying a 1/2" BSP x !/4 PT Reducer that these are not as they advertised as 1/4PT .....they actually look like 1/8 NPT. @BenB....can you confirm what thread size yours was ????.

[Buster]

UPDATE:- Right, 2 things to update, first one is the Chinese PT100 probes were advertised as 1/4" PT Thread.....they are in fact 1/16" NPT, found this out after I bought 2 x 1/2" BSP x 1/4" NPT reducers, wasted my money. Secondly, the 1/4" BSP PT100 Probe and seal kit ordered from AngelHombrew turned up this morning and I reset the PID back to factory and connected up the Probe. Well would you believe it....reading is spot on.....tested the range from 30'C up to 90'C against a known good Thermometer and perfect, so a lesson has been learnt. Some things from Ebay/China really ARE not worth all the hassle.

[BenB]

Good to know- mine definitely weren't 1/16 NPT as that would be an O/D of 3mm and mine was more like 6mm IIRC. Sounds like they're generally a bit rubbish... might have to ditch. Fancy making a Sous Vide to go with my PID box and it's going to be tricky to find one that matches mine in all likelyhood....

[Buster]

Good to know- mine definitely weren't 1/16 NPT as that would be an O/D of 3mm and mine was more like 6mm IIRC. Sounds like they're generally a bit rubbish... might have to ditch. Fancy making a Sous Vide to go with my PID box and it's going to be tricky to find one that matches mine in all likelyhood....

1/16" NPT OD is 7.630mm as confirmed on my Vernier Gauge and a chap who makes adapters ( context-pneumatic-supplies-cpm ) his reply through Ebay ( Quote -- Thats Ok John , that fitting is 1/16 NPT i just measured one i have here and its identical size 7.63mm )

[Fil]

even with the correct sized nut dont expect the cheap chinese probe to seal without a tiny smear of jbweld or similar between the SS sheaf and steel threaded aspect, a pin or needle to apply the tiny amount of epoxy needed works well, just ensure you pack some in all the way round.

though imho a better approach is to use a diy thermowell/thermopocket made from a compression tank connector fitting and 15mm, 10mm copper tube and an endfeed reducing fitting, a small bit of tube can be cut and flattened to make an end cap which can be filled round after soldering. the probes sensor is at its tip so as long as your probe make good positive contact with the pockets end cap it will read true (when u use a good probe..)


or if you need to use the probe 'naked' consider ignoring its threaded body and devise a compression seal on the ss sheaf itself perhaps?