thewats

Recently had to replace my 135 degree high limit switch. I did so and tried to start the heater. It gave me a new error-AGS. I cycled the mode switch a time or two and it started lighting and getting hot. Did this for about 5 minutes, then shut down-AGS again. Cycled the mode button again...and it started lighting and getting hot...this time for about 20 minutes...temperature in the spa came up to 65 degrees then shut down again. Cycled the mode button again...got the temp up to 100 degrees in the spa before it shut off. Gave up last night and started again this morning. Now it won't even light at all. The ignitor is lighting (I can see the red-hot glow through the peephole at the base of the heater). I have removed all of the inlets to confirm they are clean (they are). The tech told me maybe I need a bigger gas meter, but I have the largest one available (650 cfm). I have read on this board that the valves do not go bad...but is the Honeywell switch attached to the valve a possibility? How do I go about diagnosing that switch? I think I am getting fuel (at least I was) because it was up to 100 degrees last night...appreciate any help...