Re: Water heater issues
You will need a multimeter.
First, test your meter to be sure it's working properly. Set your meter to the AC volts setting, stick the probes into a working electrical outlet, and verify that you get a reading of about 120V. (Anywhere from 110V to 125V is OK; this is the expected voltage range for a standard outlet in North America.) Remove the probes from the outlet. Second test, set the meter to Ohms (or resistance). Touch the probes together; it should read 0 ohms. (For an analog meter, the needle will swing all the way to zero on the right. If it doesn't, tweak the ohms adjust knob. If it still doesn't, replace the battery.)
You should always test your meter against known conditions before using it to test unknown conditions. A faulty meter can lead you to incorrectly believe a live wire is dead. Then you could be dead, too.
Now test the water heater.
First, shut off the power to the water heater. After removing the covers, use the meter on the AC Volts setting to make sure the power is indeed shut off. Probe between each incoming wire and ground (the tank) -- it should be zero volts. Also probe between both incoming wires -- still should be zero volts.
Now that you've established safe working conditions, you can test the elements. Disconnect the leads to the elements and use the "ohms" setting on the meter to measure across the terminals of the element. It should read near zero ohms. If the needle doesn't move or it reads infinite ohms, the element is bad.
By the way, the lower element is most likely to fail as it gets the most use. Water heaters primarily use the lower element. If enough water is drawn off, it will switch on the upper element and off the lower.
If both elements are good, you may have a bad thermostat. The lower thermostat is pretty easy to check: meter across the terminals and if it reads zero ohms when the tank is cool, it's probably working. It would read infinite ohms if the water was hot.
The upper thermostat is more complicated, because it must switch between the upper and lower elements. Off the top of my head I can't remember the exact procedure to test the upper thermostat.
The "Senior Member" designation under my name doesn't mean I know a lot, it just means I talk a lot.I've been a DIYer since I was 12 (thanks, Dad!). I have read several books on various home improvement topics. I do not have any current code books I can refer to. I was an apprentice plumber for two years.