hot water heater wiring
Actually hot water heaters are a bit complex in how they operate. I would put this in the category of advanced electrical/troubleshooting work and would advise you to call a repair person.
Also the installation instructions can be confusing. The instructions I have looked at include wiring diagrams for many different models. And they can be wired differently depending on the specific model.
In general (keep in mind there are different models which work differently), there is an upper and lower heating element. And there is an upper and lower thermostat.
When the upper portion of the tank has cold water in it, the upper thermostat does two things. It directs all the electricity to the upper heating element ONLY (disconnects the lower element), and powers on the upper heating element.
When the upper thermostat detects that the water in the upper portion of the tank is at the set level, it does two things. It disconnects the upper heating element. And it redirects the electricity to the lower heating element.
The lower thermostat is more simple. It just turns on/off the lower heating element as it detects the temperature of the water in the lower portion of the tank. (But if the upper element is turned on, there will be no electricity provided to the lower element!)
Water heaters are designed this way intentionally. That is so they will not use a lot of electricity all at one time. Then smaller wiring can be used to power just one element at a time. And the electric company does not get a big surge of electric use at 6:00 am when everyone wakes up and takes a shower.
Being as cold water entering the tank is directed to the lower portion of the tank via a "dip tube", the lower heating element runs most of the time.
Heating elements can fail to where there is a dead short, a short to ground, or an open. And they should be tested for this when servicing a water heater.
Then the wire colors used for wiring a water heater may not be like any other home electrical wiring. Thus you would need the installation instructions (refer to the correct model number in those instructions), be able to understand the wiring diagrams, and know how to use a multimeter.
Then also when servicing a water heater, the technician should check that the wiring and circuit breaker to the water heater are the correct sizes, and that the water heater and electrical system is grounded properly. (A good overall inspection of the system.)
Also that a "T&P" (temperature and pressure) valve is installed. (Water boils at 212 degrees F. and creates steam. This can blow up a water heater and launch it through your roof! The T&P valve will open if the temperature is too hot or the pressure is too much.)
If you don't have the installation manual and wiring diagrams, the water heater manufacturer may have this on their web site.
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