I have a 50 gallon gas water heater that's just under 10 years old. We're getting inconsistent water temps out of it - last night filling up a bath I had the tap all the way hot and it was barely warm enough for the kids bath (wouldn't have been near hot enough for an adult). Other times I have to substantially open the cold to temper the water down to a good bath temperature. This is at the same time of day, with the same usage earlier (none for >8 hours), so it should be about the same. It affects all outlets, not specific to one bath or shower.
It's a Kenmore Power Miser 9. The burner appears to cycle normally - we hear it kick on after taking a shower or using significant hot water.
I flushed it a few weeks ago using the drain valve with no change. The flushed water looked clear, it wasn't obviously full of sediment, so I didn't flush the entire tank, only about 5 gallons. Would flushing it to empty make a difference?
I've so far been unable to get the anode unscrewed to check its condition, but that wouldn't effect temperature, right?
Anything else I should look into/try?