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Thread: Spa Heat Sensor Location - Not letting my spa reach above desired temp

  1. Back To Top    #1

    Join Date
    Jul 2014
    San Diego, CA

    Spa Heat Sensor Location - Not letting my spa reach above desired temp

    My problem is that my spa won't get above low 80s unless it runs for hours (at least 4 or more). I believe it is caused by the location of the heat sensor. Specifically, the heat sensor is located where it measures the temp of the water after it leaves the heater and is pumped back to the spa. So, it is measuring the temp of the water FROM THE HEATER and not the temp of the water IN THE SPA. This is causing my heater to turn off before the spa reaches the proper temp.

    So, if my desired temp is 102, then my heater turns off once the water FROM THE HEATER reaches 102. Not when my spa reaches 102.

    Therefore, my theory is that the location of the heat sensor is limiting my ability to heat my spa to the desired temp.

    A little more background...

    a) This is not a new's been like this since I've owned the house (2 years) and I don't know what the experience was for the previous owner
    b) I confirmed that the heater is working properly. I did this by placing a thermometer in the basket of the pump and confirmed that the water coming from the heater and getting pumped to the spa is 102
    c) I've experimented with turning the spa jets on/off and also manually churning the water (to try and force cooler water back to the heater...just to see the effect)...there was no meaningful impact

    1) Is the heat sensor for the spa located in the proper location (or should it be located where it would measure the temp of the water FROM the spa instead of TO the spa)?

    2) Is it okay to move the heat sensor or would moving it make it "not up to code"?

    3) If the heat sensor is in the proper location, why wouldn't this be an issue for every spa owner?

    4) I have a VS pump and for "Spa Heat" it runs at 2650. Should I increase, decrease, or stay the same?

    Any advice would be great. Thank you TFP community!
    30k gallon
    Pump: Jandy VS E-pump 1.5 hp
    Interface: AquaLink Touch
    Model: RS-8 Combo
    AquaLink: REV T.1

  2. Back To Top    #2
    Mod Squad
    Join Date
    Aug 2012
    DFW, TX

    Re: Spa Heat Sensor Location - Not letting my spa reach above desired temp

    The temp sensor should be between the pump and the filter or between the filter and the heater. Definitely not after the heater. Feel free to move it. It will be the cheapest pool repair project ever.

    And welcome to TFP!
    TFP Moderator
    If TFP helped you or saved you money - Become a TFP Supporter! <--Click here
    2012 build and pics, 20k gal gunite, black onyx pebblesheen, OK flagstone, IntellifoVS, cart filter w/Pleatco, IC40 SWG, Solartouch, 5 12'x4' solar panels, HP50HA heat pump, 8mil solar cover, borates, TF-100 test kit, SONOS, Doheny's Discovery Robot, hot tub on bleach

  3. Back To Top    #3
    wjr75's Avatar
    Join Date
    Jun 2013

    Re: Spa Heat Sensor Location - Not letting my spa reach above desired temp

    My sensor is right after the pump before the filter. The heater is after the filter so in my opinion you can move it. The sensor I have is hose clamped to the PVC pipe right before the filter and may have some thermal conductive gel where it is clamped to the PVC. Sounds like yours is installed in the wrong location.
    Inground 22k gallon gunite 15x31 main pool, 15x7 wading pool/sunning deck, hot tub/with overflow (9' octagon with limestone top) & slide NSWG, Aqua Blue Pebble Sheen
    Filter dual cartridge Sta-rite 450sq/ft, TF-100 Test Kit
    Heater Raypak 2100 400k btu cupro-nickel exchanger
    Auto pool cover, Polaris 280 auto pool cleaner, Jandy AqualinkRS8 Remote Control System

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