When you have no hot water, start with the simplest possibilities. Rule these issues out one at a time in order to troubleshoot the problem.
Gas Hot Water Heaters
If you have a gas hot water heater, make sure the pilot light is on. If the pilot light is out, your gas burner will not ignite, causing the lack of hot water. There are a few reasons this can occur.
One of the more common issues is a bad thermocouple. The thermocouple is a type of sensor that tells the gas valve to allow gas to flow to the tip of the pilot light. One end of the thermocouple is attached to the gas valve; the other end is positioned to be in the flame of the pilot burner. A small tube connects the ends of the thermocouple; heat from the pilot flame causes a small voltage (2030 millivolts), which in turn holds the gas valve open to the pilot assembly.
The thermocouple is fairly easy to replace:
- First and most importantly, make sure that the gas supply is turned off both on the gas valve and before the gas valve.
- Remove the cover to the burner compartment, and disconnect the gas tubes to the burner assembly.
- Remove the entire burner assembly and replace the thermocouple.
- Reinstall the burner assembly, reconnect the gas tubes, turn the gas back on, and relight the pilot.
You should also check for gas leaks using soapsuds around all of the gas line joints. A new thermocouple should cost in the range of $5 - $10, and it should be easy to find at your local hardware store. While you are making the repair on the thermocouple, you may want to take the opportunity to vacuum and clean the whole burner assembly and check the burner compartment for water leaks.
Another possible issue with a gas water heater is a faulty gas valve. The gas valve is located on the outside of the water heater, and it controls both the gas flow to the pilot light and gas flow to the burner itself. The gas valve should be inspected and replaced only by a professional.
The burner of the gas water heater could be another culprit if you are not getting any hot water. The burner could be rusted from a possible water leak. It could also be cracked and damaged by years of use in the water heater. The burner can be replaced in much the same way that the thermocouple is repaired, by removing the whole burner assembly from the water heater. Once you have installed the new burner, simply reinstall the burner assembly and light the pilot.
Electric Hot Water Heater
If you have an electric water heater, check the thermostat. One of the most common reasons for not having any hot water is a malfunctioning heating element, which is a hot water heater part that most homeowners can replace as a DIY project.
To replace the heating element, turn the power off at your circuit breaker, remove the cover plates to expose the element and verify that the power is off by testing the electrical connections with a noncontact voltage detector. Drain the water from the tank.
Then, use a heating element wrench and a long Phillips head screwdriver to unscrew and remove the old element. Install the new one and tighten it with the wrench; after this, you should be good to go.