We are growing weary in our attempts to repair our 15 year old Teledyne Laars Lite Model LLG325N-C heater. the persistent problem is that although it will light, it keeps cycling off before the water temperature reaches the pre-set level. Sometimes it will run for a week and then stop. Sometimes it cycles rapidly. Many different technicians have serviced it and many parts have been replaced. Pressure switch, high limit switches,pilot assembly, temperature control assembly, and most recently, the gas valve. If this doesn't work (and I don't hold much hope for it) what brand and model do you recommend for my pool? I have a 17X35 oval pool, it is 8 feet deep in the deep end. Approximately 25,000 gallons of water. I have a regular chlorine system with an automatic chlorinator. I just replaced the liner. I have a natural gas line hooked up to the existing heater. I use a Pentair sand filter with a 1.5 HP Hayward pump.
Any assistance would be greatly appreciated.