recalled water heater

I have a water heater that has a serial number within the recall range.

The recall is for the plastic down tube dissolving due to a bad batch of plastic.

How can I tell if the down tube is bad?

How do I remove it to check it?

I can remove the pluming since I installed the unit with brass to CPVC unions that come apart, but I don't know how I would remove the down tube without breaking it.

I opened the cold uniun and then drained it and it made bubbling noizes untill it was nearly empty. This makes me think that the down tube is ok, but the water seems to get cold quicker than it should.

I have some stainless steel heater elements left over from a research project and I have been thinking of changing out the bottom element anyway.

Edit: it's a 50 gallon electric "State censible" unit.
I don't know how to check or remove the anode rod. (if it even has one)

The dip tube is under the cold water nipple and I get them out with my finger. Even if it looks O.K. now it may not be in the future. If your heater falls inside the serial # recall replace the dip tube even if it looks O.K..

I suppose, I should just have them send me the free dip tube before I pull the old one out.

I turned off the breaker and checked the top and the bottom element and both are just above 6 ohms. This means that it's not the heater element.

The thermostats for both the top and bottom are both set to the lowest temperature since I don't have a pressure balancing faucet. It has been this way since I installed the unit over 6 years ago.

I am beginning to think the temperature change is due to the change in water pressure as the 20-gallon pressure tank empties and the well kicks back in at 27psi and brings it back up to 42psi.

Theory 1
The new "water saver" showerhead restricts the water flow to the point where the hot/cold valves in the old faucet are not the governing element in the mix ratio.

edit:
Test theory 1

1. Bring example to extreme to test math.
Q: Shower head really tiny and no valves in the system.
A: The temperature would be controlled only by the piping as hot water wants to rise. In my case the mixing point is below the water heater and thus cold water would flow into the hot side, thus cooling the water temperature.

2. Physical reproduction.

test

The only "real" way to test the elements is to see if they are drawing the proper amperage when they are operating. When you have the elements out of the heater you can look inside and see if the dip tube ends near the bottom, or at least in the lower third, of the tank.

Go ahead and have them send you the new tube. Just by looking at it, you'll get a clue of how the old one is installed, and it never hurts to have it on hand. Certainly doesn't take up storage space -- just tape it to the side of the WH. Or, just take the preventive-maintenance attitude and change it now.