There are several things that can wear out or stop working on your water heater, resulting in what may seem like the hot water is not working.
Once you have identified the source of the problem, a trip to a major hardware store and a few common tools can get things heated up again.
No Hot Water – Electric Water Heaters
There are only a few reasons why an electric water heater will not function at all. Start troubleshooting by looking at these areas:
Faulty Heating Element
A heating element can fail and is actually one of the most common (eventual) problems on an electric water heater. Water heater element replacement would be necessary but fortunately it’s pretty simple.
The upper thermostat on an electric water heater actually controls both the upper and lower heating elements. This causes the dreaded hot water not working situation. The lower thermostat controls only the lower heating element so if it fails (but the upper thermostat works), the result is hot water not getting hot enough. Solution: Replace the thermostat.
Tripped Circuit Breaker
Check your circuit breaker box to see if the breaker for the water heater has been tripped. A water heater (like other major appliances) demands its own dedicated electrical circuit. The water heater breaker should be easy to spot if tripped–it won’t be in-line with the other breakers in the box.
To reset it, simply flip the breaker to the “off” position and then to the “on” position. If it trips again, you will need to call an electrician to diagnose the issue.
Other Causes of Hot Water Not Working:
Look for foreign objects shorting across wiring connections.
Tripped Reset Button
Tripping repeatedly could be the sign of a failed reset button. First try resetting the water heater and if that doesn’t do anything, you will likely need to replace the component.
Frayed or scratched wiring could lead to a direct short. Replace all defective wiring immediately to prevent potential fire.
If you don’t have hot water, it’ll be pretty obvious if a water leak is the problem since it won’t be a typical slow drip type leak. Leaking connections can sometimes be tightened, and can be replaced if tightening does not work. Many water heater leaks can be easily fixed but a leaking tank means the water heater must be replaced.
Undersized Fuse or Breaker
Replace the faulty device with one rated for more amperage. This is not something that would likely occur out of nowhere but if you’ve just replaced your water heater with a newer model, it may be the culprit.
This is especially true with older homes, but circuit breakers can fail over time and need to be replaced. Replace the breaker.
No Hot Water – Gas Water Heaters
Gas units have different problems than electric ones, but both types can usually be repaired. When dealing with natural gas, extra precautions are necessary and do-it-yourself repair should only be done if you feel 100% confident in your abilities. Otherwise, see the form above to at least get a free quote from a local plumbing expert.
If there is no hot water in your home, here are some common causes to check:
No Gas Supply
Something is preventing gas from reaching the pilot light and burner. The gas supply may have been inadvertently shut off. Simply make sure that the gas is on and the gas valve is not in the closed position. If that was the case, open the valve and follow the steps on relighting the pilot light.
Pilot Light is Out
If the pilot light is not lit but you do have gas flow, check the components below.
The tip of the thermocouple should be in the flame of the pilot light and must be tightly connected to the gas line. If these things check out, look for blockage in the thermocouple and replace the thermocouple if necessary.
Air in Line
Verify the gas flow and relight the pilot light several times to force air out of the line.
Clogged Pilot Orifice
This component can be removed and cleaned to improve water heater operation.
Clogged, Bent or Defective Supply Line
Pinholes in the gas line can cause intermittent heating. Replace defective lines immediately.
Defective Gas Control Valve
This component can prevent gas from reaching the pilot or burner. Gas valves cannot be repaired, but are inexpensive to replace.
Dirty or Clogged Burner
Soot can build upon the main burner, preventing proper heating or even blocking burner ignition entirely. Remove the part and clean it.
The flue can become obstructed by external events such as storms or rodents. Cleaning the flue is not difficult but has the tendency to be messy. Excessive or unusual winds can blow down the flue, extinguishing the pilot.
Water is Not Hot Enough
If the unit is still functioning, but produces intermittent results, you may have components of the system beginning to fail. If you are certain that the water heater is large enough for the desired application, one of the following suggestions is most likely the component in need of repair:
If the temperature control is correctly set, the thermostat itself may need to be replaced. As mentioned above, a failed thermostat is often the culprit when hot what is not hot enough.
Sediment build up on a gas water heater’s burner can prevent the water from heating correctly. While rare, burner assemblies themselves can fail over time. DIY replacement can be done but it’s recommended to let the pros handle it.
Examine Dip Tube
While failure of this component is not common, it does happen on occasion. It’s unlikely you have one of the 20 million water heaters manufactured between 1993 and 1996 with brittle polypropylene tubes, but even those in the past few years have no guarantee against failure. If it has failed, you will need to replace the water heater dip tube.
Loose connections on an electric water hear can cause the unit to function erratically. Turn off power to the unit and confirm that all connections are tight and free of corrosion. This issue is quite uncommon but worth checking anyway.
A leak in the tank itself could prevent water from reaching the desired water heater temperature. Leaking tanks can lead to water damage, short circuits or even a fire. Replacing the water heater is the only solution for this problem.
Are you looking for a little bit more specific advice? Check out A.O. Smith Water Heater Manuals.