Question about Jandy Laars LX Pool Heater / 400,000 BTU / Natural Gas

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Heats to 72 degrees

My unit will heat the spa to only 72 degree when it is set for 100. There are no error codes. Anybody have any idea what I should check?

Posted by Anonymous on

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  • Jandy Master
  • 1,448 Answers

Try setting heater all the way to 104 the aqualink should control the heat

Posted on Dec 01, 2014

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Posted on Jan 02, 2017

  • 246 Answers

SOURCE: Spa will not heat more than 85 degrees or so

on the back of the board is the bottom for seting the max temp follow the intruction from the manual or get one at

Posted on Sep 01, 2009

  • 990 Answers

SOURCE: My water temp is reading 50 degrees too high.

This is probally your temp sensor. It will be mounted in one of your pipes and held in place with a stanless steel clamp.and have a wire running back to your control box and plugs in on the low voltage side of the control. good luck.

Posted on Dec 19, 2009

  • 990 Answers

SOURCE: My indoor RS4 panel says the spa is heating, and

If the heater is set to 104 then this is probally your Aqualink temp sensor. This is mounted in a pipe with a stanless steel clamp holding it in place. If you follow the wire back to the controler box it just unplugs and the new one goes right back in. Easy to do and the part is inexpensive.

Posted on Dec 21, 2009

  • 990 Answers

SOURCE: JVA 2440 rotates continuously in spa mode

If you remove the handel and open thr top of the actuator you will see a set nut on the center of the shaft that you use to set where the valve stops. If this is tight then you may have a bad micro switch in the unit and you should replace the actuator. Good luck.

Posted on Jan 20, 2010

Daniel S
  • 4323 Answers

SOURCE: The spa heater says the


1. Turn off the power to both the pool/spa control system and the heater unit.
2. Remove the front panel door from the front of the heater to access the raceway.
3. Run the wires from the pool/spa control system through the opening, Thermostat is located on the lower right or left hand side of the heater.
Please check this link for more details---
Jandy LXI 300 POOL HEATER Manual

Hope this helps... If it does please do not forget to accept the solution or post back for assistance.


Posted on Aug 21, 2010

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if hook up to the firemans switch turn heater all the way to 104 degrees if using 4 pin connector for aqua link to heater set spa temp to 104 and make sure on aqualink spa heat is enabled and 104 degrees

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HI I have my hot tub at 104 but it will only heat up to about 80 degrees. what is my problem

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