Water Heaters - Heat Element OHM Readings

Hello,
I have an Intertherm 40 gal mobile home electric water heater. We have recently had a limited supply of hot water in the mornings (1 hot to warm shower) It appears to be better shortly thereafter but if no one uses the hot for a while it repeats. After doing a ton of reading online, I bought a multimeter to check the Ohm readings on the heating elements. The top one reads 0 and the bottom around 9 or 10 on the X1k setting on my multimeter. Both of these readings fit into the info I have read. (neither is at the left of the scale) My question is...what gives :) I am not an expert and wont pretend to be but I can read and learn and do. But I am confused by the different readings that seem to indicate both elements are OK. I throw myself on the mercy of the experts here. What should they read? Do you think I have a replacement issue here? I am trying to find out the age of the unit. I was under the impression it was new when we moved in 3 years ago but can find no documentation to support that. Trying to get the original installer to return a call to see if they know when it was installed. Any insight would be greatly appreciated. Thanks.

Well, I don't know the required resistance, however it seems there should be some. At 9 ohms and 220 volts you get 5,400 watts which seem reasonable. Zero does not compute.

Not sure, anyone else?
Bud

Remember that you must remove the wires before taking a resistance (ohms) reading.

Zero ohms would indicate a short circuit. That would cause the circuit breaker to open. Infinite ohms indicates an open circuit, i.e. the heating element is burnt out and needs replacement.

To calculate the approximate resistance of a good element you need to first divide the rated wattage of the element by the applied voltage, usually 240 volts. This gives you the amperage of the element. Then divide the voltage by the amperage to get the resistance.

I did disconnect the wires before testing. They are rated at 4500 so quick math is around 12 ohm. knowing that, do you think the one reading 0 is shorting and needs replacing? I am confused after seeing some posts on other DIY forums saying "if the needle goes way right you are ok." I got the impression that there should be some resistance. Also, I understand hot water rises, but should the bottom of the tank (inner part of the metal wall where the thermo and element are attached) be cold while it is quite warm at the top? I guess I would think it should be somewhat warm near the bottom since it appears the bottom element is working properly? Just for further info, it has been sub zero here in Michigan for the last week or so (as it probably has for you guys also), I had a different house that the water heater seemed to act similar when it got really cold like this. Perhaps just wishful thinking on my part.
Thanks.

Just jumping in. If you get no reading on the one element, replace it. Just be sure to turn off the breaker and drain the water to below the level of the element, and refill the heater before energizing it.