Check that you are getting voltage from the thermocouple. You should see about 600 millivolts.
I cannot find a current listing for Teledyne Laars. As far as I can tell, Teledyne and Laars separated, Laars joined up with Waterpik and then got reorganized under Jandy. www.jandy.com now has the Laars Lite2 line of pool heaters with the LG model almost identical to the Teledyne Laars LLG. You can access the manual at http://www.jandy.com/pdfs/H02359-.pdf . Jandy also has a parts list for older discontinued models.
Try this link www.jandy.com Ken
go to their website and support and download it
You might want to try Jandy.com k
Try google Jandy.com
You can find every part you need for your boiler at gasboilerspareparts.com
I was told by Teledyne Laars that your pilot generator needs to produce at least 500mv to open the gas valve. Mine makes 350mv and will not open the valve. Hmm, I think that should be nearer to 600 mv - 700 mv.
Write or inquire thru that web site for a manual to be sent to you. k
Pool heaters are needed to help keep the pool water at a comfortable temperature. A Teledyne laars series 2 model esg pool manual is usually available with the manufacture.
Probably a bad sensor. Have a professional diagnose the problem. It can be very dangerous for untrained to work on gas appliances.
Use the manual provided with the heater. Each heater has somewhat different controls etc. If everything is already hooked up you may just have to turn a switch or two and turn up the thermostat.
Lighting this heater appears to have a number of warning messages associated with it. It is typically best to go to the source for such things, so see the link below for the manual PDF file. Look at page 29.