No hot water, no problem, fix it yourself!
Your water heater is one of the most expensive components in your plumbing system. It costs a lot of money to buy and more money to operate. If your water heater is not working properly, it can make your life miserable. Unless you really like cold showers, it’s a big deal when your water heater has trouble.
When to call a plumber
This is a good time to talk a bit about when it’s appropriate for you to fix things yourself and when you should probably call a plumber. Water heater problems are a good example of when this choice matters.
If the water heater itself is leaking, as opposed to the plumbing connected to it, this probably means it needs to be replaced. It is virtually impossible to repair a leaking water heater. If you can’t say for sure that you know how to install a water heater, you really have to be careful.
Replacing a water heater raises a lot of safety concerns and there are some pretty technical skills required to get the job done right. It’s generally best to call a licensed plumber if yours needs to be replaced. Licensed plumbers know how to install a gas water heater without creating a potentially dangerous situation (and how to install an electric water heater without getting electrocuted in the process).
You can do it!
On the other hand, if you have a leak-free water heater and you don’t have hot water, you can often fix it yourself without calling a plumber. You don’t need any really technical skills to learn how to troubleshoot water heaters, just a little common sense and patience.
The first good news is that while the trend is toward cheaper water heaters, the basic operation and controls haven’t changed much over the years. So some basic knowledge will allow you to troubleshoot water heaters of almost any age or manufacturer.
Gas or electricity?
There are two main types of storage water heaters (we won’t go into tankless models here): gas and electric. This indicates what type of energy source is used to heat the water.
Gas water heaters
Gas water heaters use natural gas (and sometimes LP) to power a burner which in turn heats the water like a pot on the stove. They have only a few components that control whether or not you have hot water.
The first thing to check if you have a gas water heater and you don’t have hot water is whether it has gas or not. I know it sounds silly, but I have been to many houses only to find that the gas had been turned off for one reason or another. If you have a gas stove, see if it works. If not, check your meter to make sure it is on.
If you have gasoline, the next step is to check the pilot light and, if it is off, try to light it. The lighting instructions are usually on the water heater. If the gas has been turned off, it may take a while for the air to come out and the gas will reach the pilot, so be patient.
Thermocouple
If your pilot does not light or does not stay lit, the thermocouple may be the problem. This looks like a copper wire coming out of the control box at the front of the water heater and down to where the pilot light should be. It has an enlarged tip on the pilot end.
The thermocouple is placed with its end enlarged in the pilot flame. This heat from the pilot flame causes a small electrical signal to be sent to the control valve, indicating to the control valve that a flame is present, so it is okay to let gas flow to the main burner when the thermostat calls for heat. . You can change a thermocouple in most water heaters with just a small adjustable wrench. Just make sure the end of the bulb is properly seated in the pilot flame. You can get a new thermocouple at most hardware stores for under $ 20. This will usually correct a pilot light problem.
In newer water heaters, the combustion chamber may be sealed. If you have one of these, there will usually be a small inspection window that you can look through to check the pilot. You may need to call the manufacturer for a complete pilot assembly and new cover seal to repair these models, but the procedure remains pretty much the same once you get the parts. These parts are usually covered by the manufacturer’s warranty.
Gas control valve
If you are sure you have gas and replacing the thermocouple doesn’t fix the problem, the gas control valve is the only thing left to check. This is quite a major repair, so if you are not very comfortable working with gas connections, you may want to call a licensed plumber for it.
Electric water heaters
Electric water heaters use, you guessed it, electricity, to heat water. If your electric water heater is not working, the first thing to do is check the circuit breaker or fuse box. Many electric water heaters also have a separate disconnect box on the water heater, check this as well.
If you are sure you have power, the problem is the heating elements or thermostats. Most electric water heaters have two of each, top and bottom. To check or replace a water heating element, you will need to turn off the circuit breaker serving the water heater circuit and remove the access cover from the water heater. At this point, you might get lucky and find the easiest way to repair an electric water heater.
The reset button
Many thermostats have a reset button that can sometimes be pressed to reset the circuit and get the water heater working again. To find it, you may need to carefully remove any insulation covering the thermostat. If the reset button has tripped, you should be able to hear and feel a definite click when you press it. If you think it went off, put everything back together, turn on the power, and check for hot water in about an hour.
If the thermostat cannot be reset, you will need a voltage meter or continuity tester before proceeding. There is no space in an article to cover electrical diagnostics, but you can run a simple continuity check on the elements to make sure they do a complete circuit.
Heating elements
First, Make sure the water heater is off! Then locate the heating elements. The elements will have two cables connected to each and will have a large hex nut where they are screwed to the tank or they will be fastened to the tank with a bracket and usually 4 bolts. After confirming that the power to the water heater is off, remove the 2 wires from the element and check for continuity. If there is no intact circuit between the two terminals of the element, it is bad.
If one or both of the items are faulty, it is probably a good idea to replace them. You will need to turn off the water and drain the water heater to replace the elements. If they are hex nut style, you may need a special socket. You can usually find these tools where you buy the items. Make sure the water heater is completely full and all air is out of the system before turning it back on or you will ruin new items by “dry firing” them.
Thermostats
If the elements are OK and do not need to be replaced, it is probably the thermostat (s). It is a good idea to replace both thermostats if there are two, they are quite inexpensive. Simply remove the cables, connect the new one the same as the old one, replace the access plate, and turn the power back on. You should have hot water in about an hour.
Know your limitations!
Learning how to troubleshoot water heaters can be fairly simple, but you must understand and be comfortable working with gas and electricity. Either one can literally kill you if you don’t observe proper safety precautions. If you are unqualified or unsure about something, it is better to be safe than sorry.