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Outdoor Sensor

Can I use a Munchkin outdoor sensor to replace a Viessmann outdoor sensor?  Are they both 10K?
Often wrong, never in doubt.


  • IronmanIronman Member Posts: 3,542

    Not sure some use 12k. If you download the manuals for both, the info is probably there. I've got it on my laptop, but it's down at the moment.

    As I'm sure you know the 10k is at 77*, so if you could check it at that temp. Most Tekmar sensors are 10k.
    Bob Boan

    You can choose to do what you want, but you cannot choose the consequences.
  • IronmanIronman Member Posts: 3,542
    Munchkin Sensor

    Just checked the Munchkin manual. The outdoor sensor is 12k and the indirect sensor is 10k.
    Bob Boan

    You can choose to do what you want, but you cannot choose the consequences.
  • SWEISWEI Member Posts: 7,356
    And just for the record

    there a number of different 10k curves.  Type 3 is probably the most common (most newer DDC systems) but there is a fair amount of Type 2 in use along with a few oddballs (especially on older systems.)

    Honeywell MCBA (used in a LOT of mod/con boilers) uses 12k.  I have yet to locate a full table for those, but Dale has a spreadsheet that generates them from Steinhart–Hart parameters.
  • hot rodhot rod Member Posts: 7,080
    sensors are not always interchangable

    even if they are the same resistance spec. I've tried this with a number of the Euro style solar controllers and some of the Euro boiler controls that all use PT1000 sensors.

    There are also postiive and negative coefficient sensors PTC and NTC, resistance changes on temperature rise, or temperature fall. So unless you know the spec of the thermistor it may or may not work, or work properly.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • It's never

    straightforward is it?  Especially with electronics.  I guess it is what makes our job interesting, although it would be nice to have a "fits-all" sensor.

    Thanks for your help, guys.
    Often wrong, never in doubt.
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