wrote in message news
On Tue, 16 Feb 2016 17:28:10 -0600, SeaNymph
wrote:

I apologize if this was discussed before my time.

We have an 85 gallon Marathon water heater, which I really like. I've
read different things about periodically training water heaters and I
don't know what to believe.

I'm not sure if its necessary, just wondering what others think.

Yes, at least once a year. Twice is better.

I have always heard this and never done it. Unless there's something I don't know, which is very likely, the sediment would be in the bottom. If the valve is in the bottom, sediment would flow out first. If the valve is 6-inch above the bottom like mine and unless there is a pipe inside taking water from the very bottom of the tank, the sediment would never drain out.

I did test the pressure relief valve every few months on a previous water heater as recommended, starting when it was a couple of years old. Within a couple of years it got so it wouldn't reseat completely and always dripped after that.

Latest water heater sits in the corner of the garage with a drain pan underneath that is plumbed outside, and the relieve vent plumbed to outside. I'm not touching it until it stops working or blows up.