Question about Jandy Laars Lt 250,000 Btu Heater

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Heater will only heat spa water to luke warm.

The Laars LT heater will only heat the spa water to a luke warm temperature, no where near the 102 C preferred temperature. Backwashed filter to make sure that it was not a high pressure problem and still no performance to heat the spa water above luke warm.

Water temp governor on the water temp dial setting is set so that you should be able to heat spa to 105 C or so.

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  • verypgrandma Dec 22, 2008

    Thank you. I replace the temperature sensor thermistor and the hot tub returned to nominal operation and heated the spa water to a much warmer level. However, doesn't seem to heat the spa water to 104 F, but still much better than luke warm level experienced prior to temp sensor replacement. There does not appear to be a bypass mechanism on the heater, however, the manual does refer to a very complicated water flow adjustment procedure.

  • ifixpools May 11, 2010

    Its probslby still a small failurein the bypass. You should have it looked at by a pro.

  • ifixpools May 11, 2010

    Does the heater actually turn off before getting hot or it is continually running and not getting to the desired temp? If it shuts off well before 102, you have a bad temp sensor. It is basically recognizing the water at 104 and shutting down. If the heater keeps running and you can say it has slowly taken longer and longer to heat, you have a broken or stuck internal bypass assembly. with this condition, there is more water bypassing the heater than actually going through it. Symptoms of that would be a popping or knocking sound while running as the heater is acutally boiling what little water is in it.



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The water in my arctic spa hot tub took 2 weeks to get to 102 should it take that long ?

Posted on May 02, 2009

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Sounds like it may be the thermostat on the heater. You are correct to check the filter first. if it is clean then it is probably the thermostat

Posted on Feb 26, 2009


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SOURCE: I have a Jandy Laars LX Pool/Spa Heater...when I

If the unit is lighting then shutting off then repeating it isn't rectifying, means not sensing the flame. May have a bad flame sensor or ignition control. I'm guessing your AGS is indicated on the GUI also.

Posted on Mar 07, 2010

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