Thermistor issue

Equipment doesn't work? Troubleshooting? If you're handy, members can help.

#1: Post by ToM4 »

Hello to all the members

After reading and reading this forum, I eventually decided to subscribe. I don't see any presentation topic as usual. Tell me if there's one.
Pardon my english if there are some mistakes but Im' not a native english speaker.
Of course I begin with a question.

I'm currently building my own espresso machine from scratch. I will present it in an other topic. Most of the work is done but I'm struggling with My PID.
I chose a an ECM PID which was probably not the best choice but was way better looking than the usual old fashionnned PIDs.
I realized that my temp probe was not working. In order to save a little money I decided to keep the brass fitting by drilling it in order to remove the thermistor itself.
The PID reads 3K3 on the enclosure so I bought a Vishay 3300 Ohms and the PID shows a very irrealistic temperatures. When the water of the boiler is at about 25 degrees (the temp in my kitchen) the PID reads 85 degrees.
So I must have made a mistake in my choice. Does anyone know what kind of element is initially used in these probes?

thanks for reading.

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#2: Post by Pressino »

There are different thermocouple types. You may have gotten a K-type, which is I think the most commonly available. Other variants are the J-,T-, and E-types. Not sure which type the ECM PID uses. In any case just using the incorrect probe shouldn't usually result in a 60 degree error. Perhaps there's another issue. It's also important to make sure you haven't reversed the lead wires...they are polarized. Reversing them can lead to large errors.

Team HB

#3: Post by ira »

It might also be an RTD, the instructions for the PID should tell you what kinds it can use and how to hook them up.

ToM4 (original poster)

#4: Post by ToM4 (original poster) »

Thanks for these first answers. I was so sure that it was an NTC thermistor that I did not even really think of another option. On the enclosure it only reads 3k3 and IC1 on the PCB...
I found a thread on the profitec temp sensor on the forum but can't find it again. crap...
it might be an PTC or K type

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#5: Post by cafeIKE »

PIDs often have a menu to select the sensor type.

ECM uses a P6037 for many models ... P6037.html

ECM: P6037

Bonne chance!

ToM4 (original poster)

#6: Post by ToM4 (original poster) »

Hello Ian and thanks for your answer

actually y question was not really about the compatibility because I found this info but about the component used inside these probes. ;-)

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#7: Post by cafeIKE »

ECM might tell you the OEM and the OEM might tell you the sensor type...

In the long run, it will be simpler to use the OEM part than try to re-engineer one.

Team HB

#8: Post by ira »

I would guess this page contains the info about the controller you're using and another page showing the available probes. I didn't see what the probe should be other than NTC thermistor. ... -controls/

Which on second reading contains the line:

They are available in NTC or PT1000

So maybe not a Thermistor.

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#9: Post by Pressino »

Probably not the PT1000, because they specify the following:

Operating temperature: from -20 to +85°C

Team HB

#10: Post by ira »

You're right, though no good reason a pt1000 should be limited to 85C.