Question about Jandy Laars Lx 400,000 Btu Heater

1 Answer

I have a Jandy LX400 that won't ignite. Check ohms on ignitor and the0y are around 70. Check voltage at gas valve and it is 10vac vs. 24vac. Any ideas?

Posted by on


1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    Top Expert:

    An expert who has finished #1 on the weekly Top 10 Fixya Experts Leaderboard.


    An expert that got 20 achievements.


    An expert that got 10 achievements.

  • Jandy Master
  • 8,471 Answers

Check wiring 220 vs 120 volt you might have to change wires if wired 120 volt change wires on ignitor to 120 volt see schematic inside front cover

Posted on May 01, 2016


3 Suggested Answers

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi there,
Save hours of searching online or wasting money on unnecessary repairs by talking to a 6YA Expert who can help you resolve this issue over the phone in a minute or two.

Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.

Here's a link to this great service

Good luck!

Posted on Jan 02, 2017

  • 3740 Answers

SOURCE: Jandy Lite 2 325n, FL4

The ignitor has 2 fuses in the wires leading to the ignitor. I am using the wiring diagram on page 21 of ths manual:

Scroll down to the ________ line aross the page and start reading...

If you look at the ignitor wires, there are shown as white and white connecting to red and red. Follow the 2 red wires back to the control panel. Somewhere in those wires EACH of them has a an in-line fuse. Check both fuses. Your initial ignitor that you replaced may have failed and opened one of the in-line fuses in the process.

Checking the voltage across the 2 red wires on the PCB should show 120VAC. However if you read the ignitor white wires you would have to use a chassis ground to read 120VAC. Reading across the 2 white wires would show no voltage. This would be typical of a fuse failure.
I note you stated no voltage at T1 or T2 on the main board (page 43 of the manual.)
That mean the problem may be in the safety circuit that inclused 2 limit thermostats, a pressure switch and a fuse link. Upper left side of the board. pull off the 6 pin connector and read continuity across the black and red wires. No continuity = a problem with one the following:
a. Presure switch (most common due to the switch sticking from corrosion diebris blocking the tube)
b. Either of the limit switches (Thermostats)
c. Fusable link

You could make a jumper that you could jumper across test points 7 and 8 with the connector installed to see if you get a flame. Make sure you can immediately secure the unit or you can burn it up because your bypassing ALL safety circuits. I.e jumper must be instantly removable. Total test time long enough to hear the burner light and shut the unit down.

I think you have a safety circuit problem but.... that should NOT give you an FL4 reading. A problem in the red wires off of T1 and T 2 would. Since your not getting power at T1 or T2 that leads me to believe there is a problem in the safety circuit mentioned above.

Feel free to ask any questions or make any comments here at any time.

Thanks for choosing FixYa,

Posted on Aug 17, 2011

  • 1 Answer

SOURCE: Jandy Lite 2 325n, FL4

I had this exact problem. Easy fix. Because the heater is not used often, the relay to the right of the 6 pin harness was sticking. This resulted in no voltage between T1 and T2. A very light tap of the relay with a screwdriver handle loosened it and it cycles with no further issue.

Posted on Jun 03, 2013

Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

Getting ERR message on my Pentair Minimax

make sure filters are clean then check to see if voltage on both sides of pressure switch if so check to see if voltage to ignitor if so ohm out ignitor should be about 78 ohm at 70 degrees if ok then see if safety circuit is ok then check to see if 24 volts to the gas valve brown wire and yellow wire

Jul 26, 2014 | Pentair Minimax NT Heater

1 Answer

Readsfl4 surfaces ignition problems

check the fuses going to the ignitor if ok ohm out ignitor to see if shorted or open should ohm out at 78 ohms if bad replace

Jun 05, 2014 | Jandy Laars Lite 2 Pool Heater 250000 BTU ...

1 Answer

Pool heater wont ignite

see if gas on if ok voltage to both sides of pressure switch check to see if voltage to gas valve brown wire and ground or yellow wire, if voltage check ignitor if 78 ohms at 70 degrees ok if shorted or open replace also check fuses see if gas on if ok bad gas valve when starting

Aug 25, 2013 | Raypak Pool & Spa

1 Answer

Jandy lite 2 pilot won't start

check fuses that go to ignitor if ok ohm out ignitor when unplugged should be about 78 ohms if shorted or open replace if ok check safety circuit

Apr 20, 2013 | Jandy Laars Lite 2 Pool Heater 400000 BTU ...

1 Answer

Jandy heater service manual

check power in if ok check transformer if ok check gas pressure if ok check safety circuit if when firing voltage to gas valve brown wire check ignitor

Nov 25, 2011 | Jandy Laars LX Pool Heater / 400,000 BTU /...

1 Answer

Pool heater will not come on and displays a number 4 and service heater

After reading the manual at, I found the FL4 fault indicates an igniter failure.

The possible causes are:
A. Igniter circuit is open.
B. Element has a fine crack in it.
C. Igniter fault.

The recommended correction is:
A. Check fuses on igniter wires. Identify and correct
loose connections or broken wires. Refer to
qualified personnel.
B. Measure room temperature resistance and
ensure value is in the correct range. See manual
for details. Refer to qualified personnel.
C. Replace igniter. Refer to qualified personnel.

If you have a volt/ohm meter you could measure the AC voltage going to the igniter when it should come on. If you see 120 VAC then replace the igniter. If the ignitor lights up and the gas valve turns on and there is gas pressure then the heater should light up.

If the 120 VAC doesn't get to the igniter you can check the items in the above lists and if not resolved call Jandy technical support at 800-822-7933 and they should be able to help youfigure this issue out. I hope this helps.

Please vote on this answer. Thank you.

Aug 27, 2011 | Jandy Lite 2 Natural Gas Pilot Light...

1 Answer


Hello John,
Having replaced the ignitor and the gas valve having continuity the problem has be the gas safety valve bimetal is stuck. The only thing you check is amprage draw on ignitor it should be between 3.2-3.6 (as label on gas valve states) with a new ignitor and again continuty on gas valve its the gas valve its stuck and wont open.

Good luck,

Aug 09, 2011 | Maytag 27" Built-In Double Electric Wall...

1 Answer

I just replaced the igniter, I can't get it to glow there is no voltage going to it. Then the jandy lx heater goes out on an gas fault. What will cause the igniter not to have voltage!

The fuses found in the lead wires or next to where the lead wires connect to the ignition control board. Find them and confirm with an ohm meter and replace them. Be sure to check the ignitor leads for a ground fault prior to restarting the heater since a ground could have caused the old ignitor to fail and not correcting it will blow the new one as well.


May 17, 2011 | Jandy Laars LX Pool Heater / 400,000 BTU /...

Not finding what you are looking for?
Jandy Laars Lx 400,000 Btu Heater Logo

Related Topics:

103 people viewed this question

Ask a Question

Usually answered in minutes!

Top Jandy Pool & Spa Experts

David Spradling
David Spradling

Level 3 Expert

8471 Answers

Craig Butler
Craig Butler

Level 3 Expert

1723 Answers

Jay Finke
Jay Finke

Level 3 Expert

1383 Answers

Are you a Jandy Pool and Spa Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides