Laars LG heater problem

[jmclennan]

My Laars LG isn't firing up. The pilot is lit and the LED indicator is on, but it won't fire up

We had a problem with it last season for a while, but it started working on its own. I'm thinking maybe pressure switch, but my switch isn't adjustable like the manual shows. How can I find out what the problem is?

[thepoolman1]

Is this a millivolt heater? Electronic? Most problems with heaters are not heater problems, but symptoms of other areas, most often dirty/clogged filters(s), old cartridges, clogged plumbing, clogged valve(s), clogged pump. All water-flow issues need to be resolved before addressing the heater. Is thee a separate (Jandy, Compool, etc.) controller? Does it work properly?

After that, it is best to have a competent, trained heater service pro look at a heater. It is safer that way. Also, you may have more than one problem with the heater or it may not be safe to repair. Last year, most of my heater service calls involved multiple (bad switch and valve, bad t'stat and safety switch, etc.) problems per heater. Better to pay a service call than find out the hard way.

[otitis]

My heater, an H400 was working perfectly, and then decided to stop working.
I found a spider web clogging one of the gas jets in the manifold. Naturally it
was the cylinder with the flame sensor attached. Critters and dirt really do a number on these things....