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Thread: Lowering Freeze Protection Set Point

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    Lowering Freeze Protection Set Point

    Problem: I have an Aqualink / RS6 that can't be set below 38F with current software for freeze protection, causing the pump to run many extra hours per night in winter.

    Solution: Air temperature is read from a thermocouple which can be "spoofed" by simply placing a shunt resistor of determined value across the thermocouple terminals. To determine the shunt resistance for a 33F temp set point instead of 38F, I used a 1MOhm potentiometer to plot shunt resistance against temp readings on my equipment and software (473kOhm=+1F, 314kOhm=+2F, etc). I switched power off, screwed in the selected value shunt resistor into the PCBoard terminals that the thermocouple uses, and switched power back on.

    To be on the safe side, I put an Aluminum pan with 1/2in of my pool water next to the pipes to confirm the pump indeed turns on before freezing. The display will read higher air temps than actual while the shunt resistor is in, but it can be set to not be displayed on my RS6.
    10K gal, plaster, 1/2 HP pump, Sand filter
    Southeast GA, USA

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    mas985's Avatar
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    Re: Lowering Freeze Protection Set Point

    Welcome to the forum.

    My solution was to turn off freeze protection. If you don't get below freezing for more than about 8 hours, then you probably don't need it.
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

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    In the Industry

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    Re: Lowering Freeze Protection Set Point

    Quote Originally Posted by mas985
    Welcome to the forum.

    My solution was to turn off freeze protection. If you don't get below freezing for more than about 8 hours, then you probably don't need it.
    You could also just re-calibrate the sensor in the jandy software to make it think the air temperature is warmer than it is.
    20X40 30,000 gallon gunite pool

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    Re: Lowering Freeze Protection Set Point

    Agreed - a Jandy software solution would be ideal, but I can only offset the water temp thermocouple sensor for display, not the air temp thermocouple which appears to solely control freeze protection in the software. And the Jandy water temp is only good for about a 4F adjustment.

    Is there a simpler way to set a lower freeze protection trigger point than my shunt resistor without loading new code?
    10K gal, plaster, 1/2 HP pump, Sand filter
    Southeast GA, USA

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