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Adapting a 3/8" temperature probe to a 1/2" well

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Hello everyone, I purchased a buffer tank - I was expecting a 3/8" well - but the unit came with a 1/2" well. It's a closed tube - the probe is not exposed to the fluid in the tank. Can I just coat the probe with heat transfer paste, or is there a better approach? The probe is a special unit for chilled water that came with the control unit - I would like to use it.

Thanks for any comments or suggestions.

Ron
Energy Kinetics EK, Goodman GSXC72400, SpacePak ESP 2430J

Comments

  • hot_rod
    hot_rod Member Posts: 22,259
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    So the OD of the sensor is 3/8", and the well ID 1/2"?

    This is a common 1/2" well, 3/8 OD copper tube fits in just right. The ID of the copper is 5/16"

    Is it a 6 mm sensor? About 1/4" OD?

    If so I reduce those with a piece of 5/16 copper tune soldered inside 3/8" tube and you end up with a 6 mm or 1/4" ID well.'
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • RonnieJ
    RonnieJ Member Posts: 46
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    That's a great idea, Hot Rod - thank you!
    Energy Kinetics EK, Goodman GSXC72400, SpacePak ESP 2430J
  • pecmsg
    pecmsg Member Posts: 4,888
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    Depending on how quickly you want a response just transfer past is fine.

  • hot_rod
    hot_rod Member Posts: 22,259
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    These 6 mm, 1/4" sensors are becoming popular, probably a Euro based size. All mod cons I have dealt with use this size thermistor. Same size on some of the electronic set point controls Ranco, etc.

    I use 5/16" OD copper tube, just egg shape the end a tiny bit to get a friction fit in the 1/2" well. The sensor is a nice fit inside once you ream the burr.

    I prefer silicone grease to that grey thermal paste. The grey stuff seems to harden over time and lock the sensor in the well.

    Thermistors seem more prone to failure compared to the old copper cap tube style sensor.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • RonnieJ
    RonnieJ Member Posts: 46
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    Thanks guys!
    Energy Kinetics EK, Goodman GSXC72400, SpacePak ESP 2430J