I have a jandy lrz pool heater that fired up strong in early summer now wont fire up at all? gas heater 125k btu

SOURCE: Jandy, Lite 2 Pool heater wont kick in

3/4 pipe line will work and will keep heater from sooting up.

SOURCE: Raypak gas pool heater with error code HL2

Do you have power to the heater?If you do then I would look for a hi limit switch to reset.It might be the pump you have to reset.

SOURCE: Jandy Lite2 Pool heater will not stay lit after firing.

Look at the sensor that tells unit that everything is lit. There should be some sort of sensor that tells the ECU that the ingnition area is a burn temp. It sounds like the unit can't tell that flame is lit. Hope this helps.

SOURCE: Jandy LX250 LT Pool Heater High Limit Switch

Jump the High limit switch. If it fires the switch is bad

SOURCE: Pool heater will light then turns off

check gas pressure you should be getting about 10" water coloum