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

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Pressure switch light going off and heater won't start

I am having a pressure switch alarm on an lt400n-l heater

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  • Gretchen Andrews
    Gretchen Andrews Mar 18, 2014

    I had this problem intermittently over a 3 year period and it was driving me crazy. I found I had two separate issues both having to do with wire connection that was preventing my flame to ignite. The first was actually in the Timer box. I found that I had corrosion build up on the ground connection that prevented the ignition. I fixed this by cleaning all connections in the timer box as well as taking the precaution that other connections could be building up the same corrosive issue, I cleaned all connections I could get at in the heater and attached securely. This seemed to have solved problem for several months but then again I had same pressure switch alarm return. This time I found that I had a break in the wire connected to the Flame Sense Rod. The wire was broke, but so little that it did not become completely separated. I was able to trouble shoot this by using a jump between the wire and the connector, this also served as temporary correction until I could order the replacement part. I recommend you take the rod completely out and clean it with an emery cloth to make sure it is also not corroded.



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Back wash filter. clean out pump basket, ensure you have proper water flow. Once you have ensure proper water flow and problem still exists, you will most likely have to replace the pressure switch

Posted on Mar 18, 2014

  • Steve Slater Apr 15, 2014

    You can put filter setting on "whirlpool", "bypass to pool", or "recirculate" (depending on filter brand). This will bypass water flow past the filter. If problem is resolved then the low flow issue is inside the filter.

  • Scott Corey-reid Apr 15, 2014

    if you put filter on recirc it bypasses the filter and wont clean the water wich is pointless. You have a faulty pressure switch, poor wiring, or you havntback washed filter in ages, or the sand in your filter needs to be changed, otur cartridge filter needsto be cleaned out



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