pt1000 temp sensor

easternbob · Dec 29, 2010

I'm starting a new post to get even more of the more electrically inclined people involved.

Below was copied out of the thread titled "EKO controller temp flipping up and down" or some thing like that....

I searched around in past threads and it looks like the temp probe on the EKO is a pt-1000. Does that sound right to all those people who know about this stuff.
I found this one on line. What do you think is this the right style/model. Looks very similar to me but then again Iâ€™m a forester not an elec. engineer.
http://www.siliconsolar.com/pt1000-high-temp-sensor-p-502163.html
Not a bad price $8.76

in hot water · Dec 29, 2010

That is a 1000 ohm sensor, very common on European controls including most of the solar controllers. The red or black jacketed ones have a better outer jacket for high temperature and outdoor applications, better UV protection jacket also. For inside use, the grey jacketed ones are fine, maybe less $$.

The end is a 6mm diameter and fits just right inside 3/8 OD copper tubing if you need to build a well to attach it, use a a dab of thermal paste.

hr

easternbob · Dec 30, 2010

Can anyone tell me if this probe that is listed on NewHorizons website
http://www.newhorizonstore.com/Products/102-temperature-probe-for-rk2001u.aspx $45

Is the same style as this one I found else wheres for much less?
http://www.siliconsolar.com/pt1000-high-temp-sensor-p-502163.html

Thanks

ewdudley · Dec 30, 2010

easternbob said:
Can anyone tell me if this probe that is listed on NewHorizons website
http://www.newhorizonstore.com/Products/102-temperature-probe-for-rk2001u.aspx $45

Is the same style as this one I found else wheres for much less?
http://www.siliconsolar.com/pt1000-high-temp-sensor-p-502163.html

Thanks

For what it's worth here's the resistance table published in the manual for my RK-2001U equipped boiler. (The resistances are labeled as kOhm but I can't believe they're not just ohms.)

Code:

Scheme of dependency of resistance on the
temperature of heating water by the therm
probe ( DP PROFI )
Teplota       Odpor
  C       min kOhm    max
    -55   951   980  1009
    -50  1000  1030  1059
    -40  1105  1135  1165
    -30  1218  1247  1277
    -20  1338  1367  1396
    -10  1467  1495  1523
      0  1603  1630  1656
     10  1748  1772  1797
     20  1901  1922  1944
     25  1980  2000  2020
     30  2057  2080  2102
     40  2217  2245  2272
     50  2383  2417  2451
     60  2557  2597  2637
     70  2737  2785  2832
     80  2924  2980  3035
     90  3118  3182  3246
    100  3318  3392  3466
    110  3523  3607  3691
    120  3722  3817  3912
    125  3815  3915  4016
    130  3901  4008  4114
    140  4049  4166  4283
    150  4153  4280  4407

I believe the PT1000 gets its name from having a resistance of 1000 ohms at 0 degC, so they would appear to be different.

You might want to investigate by putting your probe in a crushed ice bath and checking its resistance to see if it is consistent with 1630 ohm spec above or the 1000 ohm pt1000 spec.

Another thing you could try would be to wire in a fixed 2K ohm resistance to the controller and see if that makes it stop jumping around, then you'll know if it's the probe or not.

Cheers --ewd

easternbob · Dec 30, 2010

ewdudley,
Well some of that is above my head, but I should be able to try an ice bath and the resistance. Do they sell pt1630 temp probes?
thanks

ewdudley · Dec 30, 2010

easternbob said:
ewdudley,
Well some of that is above my head, but I should be able to try an ice bath and the resistance. Do they sell pt1630 temp probes?
thanks

Like I say, for what it's worth they show a 1630ohm@0degC for my RK-2001U controller, but we don't know if that's the same probe used for your RK-2001U controller, and we don't even know if the table in my boiler manual is true or not. If I remember I'll put my probe in an ice bath tonight and see what resistance it reads.

It looks like the probe sold by newhorizon may be the 1630ohm@0degC probe you need and the PT1000 is a red herring. Or not. I guess I'm not being very helpful.

Assuming your probe is bad and your controller is good you can wire up a known fixed resistance to the controller and see what temperature it reads. Then look up the temperature to resistance for both the 'PT1630' and the PT1000 probes and see which one matches your controller readout.

Assuming your probe is good and your controller is bad you can put your probe in an ice bath and see if the resistance matches the 'PT1630' table or the PT1000 table.

--ewd

in hot water · Dec 30, 2010

Here is the chart for the solar controller sensors. We test sensors first in a glass of ice water, then in a pot with boiling water. Check the resistance to the chart.

I'd be glad to send you a sensor to try, if you e-mail me your address.

hr

easternbob · Dec 30, 2010

Well this will give me something to do over the long weekend. I'll report back how the icewater bath went. So long as I don't zap myself

easternbob · Dec 30, 2010

in hot water,
I just tried to email you but it got kicked back. Not sure your email address you have on this message board is current??

ewdudley · Jan 1, 2011

easternbob said:
ewdudley,
Well some of that is above my head, but I should be able to try an ice bath and the resistance. Do they sell pt1630 temp probes?
thanks

Just measured the probe on my RK-2001U with ice bath and it reads 1630 ohms, same as specified in boiler manual.

Looks like it is a PTC thermistor probe, 2k ohm @ 25 degC, which is not compatible with a PT1000 RTD sensor.

--ewd

easternbob · Jan 3, 2011

ewd,
Thanks for checking that. I tried to measure the resistance but didn't have much luck (lack of knowledge, lack of proper equipment, faulty probe?).
I've been paying more attention and it seems that the numbers flip around less when the temp is steady, but when things are heating up they flip wildly might be reading 158 one second and the next it looks like it's reading over 200 and the fan shuts down. Of course this is all happening in a spilt second so I hear relays clicking on and off it rapid secession inside the controller. Worried I'm going to wear them out.
Will google search see if I can find a probe with those peramiters.
Thanks

ewdudley · Jan 3, 2011

easternbob said:
ewd,

I tried to measure the resistance but didn't have much luck (lack of knowledge, lack of proper equipment, faulty probe?).

Will google search see if I can find a probe with those peramiters.

Your problem got me to thinking I ought to have a spare but I can't seem to find a generic version, let us know if you have any better luck.

But before you go buy another probe it could be worthwhile to prove to yourself the probe is bad. All you need is a 1.0 or 2.0 kohm resistor connected to terminals 4 and 5 of the controller and it should read a steady temperature according to the PTC2000 table above [which is in Centigrade].

If you study the resistor color code you might find one in some old junk laying around or you can pick one up for pocket change at Radio Shack, or Salina Electronics in the city. Or maybe a 5K potentiometer would be better for a dollar or two more. They would most likely be willing to help make sure you know how to set up your meter and measure resistance.

Cheers --ewd

easternbob · Jan 3, 2011

ewd,
Will it be possible for me to measure the resistance of the probe by holding the red and black leads of my multi-meter on the screws of the controller (when the wires of the probe are installed ofcourse) with the ice water bath? I was trying to hold them in the air and it wasn't working very well, alligator clips would have helped.
Will check out my options at Radio shack.
Bob

ewdudley · Jan 3, 2011

easternbob said:
ewd,
Will it be possible for me to measure the resistance of the probe by holding the red and black leads of my multi-meter on the screws of the controller (when the wires of the probe are installed ofcourse) with the ice water bath? I was trying to hold them in the air and it wasn't working very well, alligator clips would have helped.
Will check out my options at Radio shack.
Bob

It won't read what you want to read with the leads connected to the controller because of the internal circuitry of the controller, especially if the controller is powered, which would most likely raise hell with your ohmmeter.

Just disconnect from the controller and grip them with a rag or foam rubber or something in the jaws of a pair of vice grips and then you should be able to get your leads steady on the wires.

--ewd

easternbob · Jan 3, 2011

will try that and then report back.

easternbob · Jan 4, 2011

ewd,
Well I tried both things. I purchased a 2.2k ohm resistor and plugged that into the back after I removed the temp probe wires and the controller was reading 89, 91 deg F, but it was flickering back and forth between those numbers. I then put the probe in the ice water bath and the resistance was reading at 1646 ohms. So it looks like the temp probe is fine. Does that mean the controller is the problem? Can you think of anything else that might be wrong? Was hoping it would be the cheaper of the two items.....

easternbob · Jan 4, 2011

Forgot to mention. I started a new thread about controller warranty..... https://www.hearth.com/econtent/index.php/forums/viewthread/67513/

ewdudley · Jan 4, 2011

easternbob said:
ewd,
Well I tried both things. I purchased a 2.2k ohm resistor and plugged that into the back after I removed the temp probe wires and the controller was reading 89, 91 deg F, but it was flickering back and forth between those numbers. I then put the probe in the ice water bath and the resistance was reading at 1646 ohms. So it looks like the temp probe is fine. Does that mean the controller is the problem? Can you think of anything else that might be wrong? Was hoping it would be the cheaper of the two items.....

I agree the controller is defective, hopefully it is covered under warrantee. If not, at least it does sound repairable. The microcontroller appears to be running correctly, it's just getting a bad signal. You kinda need a scope at this point to verify that the power supply and reference voltages are correct and stable, and so forth.

If no warrantee is applicable you could set up to run the fan on an aquastat with a burn-timer, and the circulator on a switch. Then inspect the controller for bad solder joints and smoked components related to the thermistor input. Just get a strong magnifying glass and follow the solder traces from terminals #4 and #5 and see if there is something that doesn't look right.

At $200 you might be able to find somebody to repair it economically, but first it would be great if you could chase down the schematic.

And have your dealer check back though the supply chain, it's very possible that when the right person hears the symptoms they will confide that it's a known failure mode with a known fix.

--ewd

Medman · Apr 29, 2011

I have posted a fix for the "dancing display" issue of the EKO controller on this thread:

https://www.hearth.com/econtent/index.php/forums/viewthread/67513/

Let me know if you try it yourself.

easternbob · May 16, 2011

Medman,
Thanks for posting a reply. I ended up buy the a brand new style controller that AHONA is selling. I'm no elelctrical whiz so I didn't have the skills or tools to test it like you did. But maybe now that you have found the problem I can repair the old one and have it as a back up.
Bob

Medman · May 18, 2011

No problem Bob. It is a very simple repair to do, once you locate the faulty capacitor. You should be able to find a replacement at your local TV repair shop or online.

pt1000 temp sensor

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