Originally Posted by Comodave
Last year we had no problem getting the old aluminum anode out of the heat exchanger but this year we saw what you said, the anode seemed to swell up a bit and wouldn’t come out. We had to pull the end cap off and push it out from the inside. Not a big deal but I was wondering what had happened. Thanks for the info, now ai understand why it did that.
I see that as well, in some cases no swelling, in others it occurs. The more active the anode, the more it will generate aluminum hydroxide "fluff", or swell. It means it's working as intended.
I'd recommend heat exchanger end cap removal every 2-3 years in any event. When I remove these I almost always find debris, including dead pencil anodes, trapped in this space, and impeding water flow.