[jmon]

Well you certainly have kept up on the maintenance of it. It looks in great shape. But it is over 12 years old. So you have age as a big factor.

A new one of those defenders with power vent run about 1800 bucks or so and that's if you install it. Dip tube runs about 30 bucks.

Was anode rod(s) ever changed? They run about 30 bucks each. That model of defender I think has two of them.

Hard to tell what is actually going on inside. Your theory of dip tube sounds about right and would explain your issue. You have unions on the inlets and outlet, so it would be an easy check/replace. No cutting or soldering required.

 

[jmon]

I do have a thermometer. However, I haven’t checked the actual temperature. How do you recommend I do this? Do I simply turn the shower on as hot as possible and see if it reads 130 as that is what the hot water heater is set to.

I’ve only noticed the decline in hot water, and our downstairs shower in the kitchen sink. I have not assessed the hot water in the upstairs shower yet.

is there a way to check the integrity of the gas control valve?

Thank you for your replies. It is appreciated.

Yes, run the hot water over the thermometer see how close it is to your gas control valve setting. 120 -130 degrees is good.

In your opening post you say hot water runs out in about 5 minutes or so. Imo, that's usually indicative of a dip tube issue. However, sediment can build up on the probe of the gas control valve effecting the temp as well.