Jandy Lt400P Ran Great For 4 Years, Now Throwing Agc Error

[chrison600]

Hi all,

I have a pool with integrated hot tub that has all Jandy equipment (filter pump, filter unit, heater, chlorine gen) as well as a Polaris powered by a booster. We don't use the heater a whole lot, only when we use the hot tub. It's run great since new (about 4 years ago), but last night threw an AGC error after heating the tub to about 95 deg. If you reset the heater and fired it up again, it would go through its start up routine, try to heat the water (burners would light and fan would run for about 5 seconds, twice), then it would throw the AGC error.

I read through a few forum posts (that's how I found this forum) and it seems that the official Jandy recourse was to clean the filter or determine cause of pump oscillation. Does this generally mean that my filters need to be cleaned/changed because they're not allowing enough water to flow?

Thanks,

Chris

[Beelzy]

Hi all,

I have a pool with integrated hot tub that has all Jandy equipment (filter pump, filter unit, heater, chlorine gen) as well as a Polaris powered by a booster. We don't use the heater a whole lot, only when we use the hot tub. It's run great since new (about 4 years ago), but last night threw an AGC error after heating the tub to about 95 deg. If you reset the heater and fired it up again, it would go through its start up routine, try to heat the water (burners would light and fan would run for about 5 seconds, twice), then it would throw the AGC error.

I read through a few forum posts (that's how I found this forum) and it seems that the official Jandy recourse was to clean the filter or determine cause of pump oscillation. Does this generally mean that my filters need to be cleaned/changed because they're not allowing enough water to flow?

Thanks,

Chris

This is a good place to start, as even if the filter is not the problem it is necessary to start with a clean filter.

You also might check to see if there is a By-Pass valve near the heater headers that may be out of adjustment. Sometimes an

inadvertent movement of said valve could be diverting too much water and making the heater malfunction.

[Pool Clown]

AGC or AGS is the gas valve shutting down. This is probably happening because the heater control is not getting flame rectification. This can be due to soot on the flame rectifier, or the gas jet just below the rectifier is plugged (usually a spider web). Also could be a bad or loose ground wire (rats like to chew wires, but usually not just one). My bet would be the spider (web) in the jet. I see this more than the other two. And makes sense since you said you don't use the heater a whole lot.

[chrison600]

Hi everyone and thanks for your responses. I thought I'd post back to update that cleaning the filters did the trick. My assumption is that there wasn't enough flow through the system, so the heater self-protected itself from an overheat by simply shutting off the gas supply...

Chris

[Pool Clown]

Keep an eye on the heater. A low flow condition, would have given you a low pressure fault, not an agc/s code.