Results 1 to 11 of 11
  1. #1
    Join Date
    Oct 2008
    Location
    North East
    Posts
    1,050
    Rep Power
    19

    Require a new accurate 10k return air sensor probe



    Just a quick one,

    current return air sensor probe is 3c out of accuracy. If I buy http://uk.farnell.com/ge-sensing-the...ohm/dp/2113022 would this suit an lg unit. I'm told I need a 10k probe but I assume the +-0.1c is them guaranteeing how accurate the probe will be so I know it's gonna read the correct temperature?

    Would this work? LG want £16 for a new return air sensor, that's probably not very accurate so I want to go one better than that.

    Regards
    Richard



  2. #2
    Join Date
    Oct 2008
    Location
    North East
    Posts
    1,050
    Rep Power
    19

    Re: Require a new accurate 10k return air sensor probe

    Or I could go for a 0.2% accuracy http://uk.farnell.com/betatherm/10k3...rad/dp/9707271

    or a 0.5% accuracy - http://uk.farnell.com/betatherm/10k3...-rad/dp/970720

    assuming lg's are NTC

  3. #3
    Join Date
    Oct 2007
    Location
    manchester
    Age
    50
    Posts
    5,707
    Rep Power
    45

    Re: Require a new accurate 10k return air sensor probe

    the lg sensor will be plastic coated thus theres a delay in sensing temperature where as most thermistors ie farnell,trend,titan etc will be just a bead thermistor so will be more sensitive- theyre prob all made in the same factory so you wont notice much difference in the accuracy

  4. #4
    Join Date
    Oct 2008
    Location
    North East
    Posts
    1,050
    Rep Power
    19

    Re: Require a new accurate 10k return air sensor probe

    Quote Originally Posted by install monkey View Post
    the lg sensor will be plastic coated thus theres a delay in sensing temperature where as most thermistors ie farnell,trend,titan etc will be just a bead thermistor so will be more sensitive- theyre prob all made in the same factory so you wont notice much difference in the accuracy
    all the above are plastic coated. The lg ones are rubbish they are all out by about 1.5-2c which isn't very good at all. The above are either ge & betatherm.

  5. #5
    Join Date
    Oct 2008
    Location
    North East
    Posts
    1,050
    Rep Power
    19

    Re: Require a new accurate 10k return air sensor probe

    Evening.

    fitted sensors and all working ok but I now want to replace the ones that are in the wired controllers. Tried the same sensors that I put on the indoor units but these don't work, they read 14c at 21c actual room temp. Lg won't tell me what sensor is used and say you have to buy a whole new controller which is rediculous.

    The others I installed are working very well now however there is one room still that has to use the on-board sensor inside the wired controller this is due to room temperature been incorrectly sentenced at the indoor unit itself so it is better to use the wired controller sensor. Not sure what to do now any advice please attached is a picture of the controller sensor.

    Thanks
    Attached Images Attached Images

  6. #6
    Join Date
    Feb 2007
    Location
    UK
    Posts
    2,479
    Rep Power
    45

    Re: Require a new accurate 10k return air sensor probe

    Bearing in mind that most AC manufacturers only use sensors with 2 different characteristics in their systems, one for high temperatures like discharge and another one for everything else... I would try with the same sensors you used for the indoor units themselves.


  7. #7
    Join Date
    Oct 2008
    Location
    North East
    Posts
    1,050
    Rep Power
    19

    Re: Require a new accurate 10k return air sensor probe

    Tried that, they do the same as above. The ones fitted to the indoor units work perfectly & they do not appear compatible on the same performance curve as the ones in the controller I.e 10kohm

  8. #8
    Join Date
    Jun 2011
    Location
    Australia
    Age
    44
    Posts
    337
    Rep Power
    21

    Re: Require a new accurate 10k return air sensor probe

    Hi Buddy,

    A bit of a stuff about but here goes..

    Provided you can read (from a display) the temperature sensor in question, cut the wires of the temperature sensor & fit an adjustable potentiometer (variable resistor) - sweep back & forward by adjusting the potentiometer trying to achieve a displayed value between 15°C & 30°C

    Note, it may be necessary to connect a combination of resistors / potentiometer to get this range.

    Then, at increments of 15°C, 20°C, 25°C & 30°C disconnect the potentiometer record the measured value (by multimeter) in ohms...

    Then refer to tables in this publication (page 72?) & see if you can find a match;

    https://www.sontay.com/media/cms_pag..._Catalogue.pdf

    Good luck!

  9. #9
    Join Date
    Oct 2008
    Location
    North East
    Posts
    1,050
    Rep Power
    19

    Re: Require a new accurate 10k return air sensor probe

    Quote Originally Posted by HVACRsaurus View Post
    Hi Buddy,

    A bit of a stuff about but here goes..

    Provided you can read (from a display) the temperature sensor in question, cut the wires of the temperature sensor & fit an adjustable potentiometer (variable resistor) - sweep back & forward by adjusting the potentiometer trying to achieve a displayed value between 15°C & 30°C

    Note, it may be necessary to connect a combination of resistors / potentiometer to get this range.

    Then, at increments of 15°C, 20°C, 25°C & 30°C disconnect the potentiometer record the measured value (by multimeter) in ohms...

    Then refer to tables in this publication (page 72?) & see if you can find a match;

    https://www.sontay.com/media/cms_pag..._Catalogue.pdf

    Good luck!
    thank you but I don't have any of that equipment to be able to test it.

    Ive just sent this email to the technicals manager:

    Hi Mark

    I am trying to replace the thermistor on one of my wired remote controllers. To do this I can buy a thermistor at £2-£3, but I need to know what type of thermistor is required. the indoor units use a 10k NTC thermistor however this gives a wrong reading when used on the wired controllers so this must use a different resistance. I find it disgraceful that the technical department cannot advise me what thermistor is used as it is "sensitive information". When I questioned Ken that lg deem it acceptable to throw a perfectly working controller away in order to buy a new one that has a accurate temp thermistor sensor he said that it is acceptable.

    A company that claims to pride itself on environmental issues and saving the environment you seem happy to for me to spend another £150 or so on a new controller and send this one to landfill that is really not very responsible. I'm only asking for the resistance of the thermistor used so it can be replaced responsibly I'm not asking for confidential information. You openly advertise what sensor is used in the actual indoor units themselves or the outdoor units for testing purposes so I am not sure why you cannot find out what is used for the wired controller.

    I am really unhappy at this response from lg I am hardly asking for detailed information. I would be great full if you could ask for this piece of information for me as over the years I have spent a lot of money on unnecessary parts. Mitsubishi and daikin happy to tell you this info.. The system is now up and running properly albeit this one last thing that needs sorting so this will be the last you hear of me. You've got nearly 1k in parts from me over the course of this year and to spend £150 on a new controller just for the thermistor is daylight robbery. If this is the case I can see why most the engineers on forums avoid LG air con. Please tell me this isn't the case.

    Thank you.
    Richard.

    Sent from my iPhone

  10. #10
    Join Date
    Apr 2008
    Location
    Southampton, England
    Age
    49
    Posts
    1,044
    Rep Power
    35

    Re: Require a new accurate 10k return air sensor probe

    Hi Richard,

    Wouldn't surprise me if LG UK wouldn't have that info to hand. I suspect they would have to request it from the main factory in Korea.

    Can you unsolder the thing and check its resistance over a limited range - say 0 to 50 degrees? You could stick an ohmmeter on it and a thermometer next to it and stick it in the fridge then into a warm oven then make a graph up and see how it comes out.

    Or and bit bodge it and scarper but...

    If you are able to hide the cable, use one of the new probes on a long length of wire and just use this as an extended version of the one in the unit.
    Health and safety first..........unless I'm in a hurry.

  11. #11
    Join Date
    Oct 2008
    Location
    North East
    Posts
    1,050
    Rep Power
    19

    Re: Require a new accurate 10k return air sensor probe

    If I was to extend the sensor on a cable it would look unsightly as these are flush on the wall. I need to get hold of something to check the resistance. I'm sure it's just a standard one, lg technical have a test lab theirselves there, I would expect them to know this info or be able to at least ask Korea for me. You would think they were ruled by their ruler in south Korea!

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •