troubleshooting help

Hello everyone, I'm new a complete novice when it comes to pool maintenance. I've recently moved into a house with a 10,000-gallon pool and spent the last month or so learning as much as I can to make sure this thing doesn't blow up. My current setup includes a Hayward DE filter, a Centurion...

I have a Mastertemp 250, I installed it less than a month ago. It was working great until last week. I started to get AFS and IGN errors, more often the IGN error though. The heater will try to start up and begin the firing process just fine, the igniter lights the gas, the exhaust gets hot...