I have a Pentair 200 pool heater on Natural gas. I had turned this heater on when I first opened the pool and it fired up well. Then I decided to power wash it as I was cleaning my deck. Bad idea. I killed the membrane pad. So I vacuumed and cleaned out the inside of the heater (with some forced air) and replaced the membrane pad, now that a button was not working. After everything was done, I cranked it up. The membrane pad worked great. But as soon as the valve opened and the ignitor fired, I got a loud bang that sounds like a backfire. It kept banging over and over again until I finally turned it off. Here is a link if you want to hear/see what I mean. <
>. I ordered a new igniter just to see if that might be the issue. I pulled the old igniter out and it pretty much crumbled in my hands, though that might have been my fault for touching it. I have had this heater for 10 years and never had a problem with anything. The gas flow should be fine, but I haven't tested it. I have a call into Pentair, but does anyone have any suggestions?