Water heater repair
May 31, 2010
Water heaters sit alone in a corner of the house, completely abandoned and ignored. Often silent, they provide a basic necessity with no notice until something goes wrong.
My wife (who insists on showers hot enough to cook some foods), recently informed me that the shower was no longer staying warm. It turns out that it was indeed getting colder much faster than normal.
Of course, all the places I have lived so far put the heater in the least accessible place…
Essentally water heaters are just tanks of water with a heat source in them. Mine happens to be electric. This was the troubleshooting process:
1) Turn off the power. It is an electric water heater, meaning that it is plugged in. It is also plugged into a much higher voltage than outlets. Electricity can (and does) kill. This didn’t scare me off, but it is a good reason to be careful.
2) Take off the insulation around the heater. The sides may not feel hot, but it is losing heat, especially if it is in an unheated area.
4) Remove the covers from the two panels, these cover the back of the elements and the thermostats.
5) Remove one of the two wires from each of the two elements (they are the large hex nuts with wires coming out of them)
6) Using the multimeter, check the resistance of the element. For a 4500W heater like mine, the value is ~13Ohms. If the reading is really high, or reads OL or something like that, the element is ‘open’ and needs to be replaced.
7) If the resistance of the elements look ok, check the thermostats. They are the little boxes above the elements. After reconnecting the wires to the elements, turn on the power to the heater. Now I have to be extra careful.
Measuring the voltage at the elements will show whether they are getting power or not. When the tank is all cold, the top element will be on, once the water at the top heats up, the bottom element cycles on, and runs until the water at the bottom is warm enough before turning off.
Basically, the goal is to make sure that each element is getting power. This is done by checking the voltage at the top and bottom elements with the thermostats cranked hard over each direction. If no power is found at one or both elements after checking all combinations, chances are that there is a problem with one or both of the thermostats.
As a side note, I made sure that the thermostats were actually contacting the tank, if they are not, they will inaccurately read the water temp and not heat correctly.
8 ) The thermostats passed the test, so lastly I checked the dip tube. This is a plastic pipe that extends down into the tank at the cold water inlet. It allows the tank to fill from the bottom up with cold water, keeping the hot from mixing and giving you cold water right away. To do this, the cold water inlet is unscrewed from the tank. A plumber significantly stronger than I (or a chimp) installed the inlet, outlet, and anode on the tank, and it took a tool of considerable size to get the cold water inlet off.
The dip tube sits on a lip just below the inlet. My tank had about .125″ of the ~40″ tube left. Ah ha!
Dip tubes can be purchased for about $3. I got one, cut it to length, installed it, and the problem is solved! Showers are now hot enough, and we don’t have to take turns with the dish washer to ensure there will be enough water.
OTHER) It is a good idea to drain the tank periodically if it is not self cleaning. If the anode can be removed, it should (according to the manufacturer) have less than 6″ of core wire exposed. Unfortunately, the ape that put my tank together got the anode on so tight that my brother and I rounded the nut off and tore the tank from it’s earthquake straps before giving up.
Disclaimer: I con’t claim to be an expert and am just relaying anecdotes, so I can’t claim any responsibility for harm or damage you cause while fighting chaos yourself…
