The 9 most common part(s) or condition(s) which contribute to the symptom Water Heater does Not Heat are listed below. Check or test each item and watch any available videos. If you are still unable to solve the problem you may need to do additional research and troubleshooting. Remember, with our 365 Days. Period.® return policy you can return any part for any reason. So, go ahead and buy it to try it. No other parts retailer offers this unconditional return policy.
For the symptom you selected, these are the most common parts or causes, ordered by the likelihood of fixing the symptom.
If the water heater does not heat than the thermocouple may have failed and will need to be replaced. On gas water heaters that use a standing pilot a thermocouple style flame sensor might be used to detect the pilot flame. The other end of the thermocouple attaches to a gas valve and thermostat assembly. Usually when a thermocouple fails the pilot can be lit but drops out as soon as the button on the gas valve is released.
If the hot water does not heat than the pilot may have become restricted. If the pilot can not be lit or has a low flame then the pilot is likely plugged with carbon deposits. Sometimes the pilots can be removed and blown out with compressed air to try and clear it, but usually a restriction requires replacement of the pilot assembly.
If the water heater does not heat, the gas valve and thermostat assembly may be defective. If the ignition source is working, weather it be a pilot, igniter or sparker and there is gas pressure at the inlet of the gas valve the Gas valve and thermostat assembly may not be letting gas thru to the burner and will need to be replaced.
If the water heater does not heat the draft inducer motor might be bad. The draft inducer fan motor draws air into the burner and then exhausts it out the flue. The air flow through the draft inducer assembly also closes a vacuum switch to signal the control that proper air flow is present. If the water heater does not heat the inducer motor may be running slow from bad bearings, etc. or have a plugged vacuum port and unable to close the vacuum switch which causes the ignition process to stall.
If the water heater does not heat the ignition module may be defective. The ignition module cycles the igniter or sparker on to light the burner. If there is power to the ignition module but the burner will not light, the ignition module may need to be replaced. Note: After three or four failed attempts to light the burner the module will lockout and will need to have the power turned off and back on to reset it. This may not be the fault of the ignition module but the result of a bad igniter or flame sensor.
If the water heater does not heat the heating element may have failed and will need to be replaced. The element can be checked with a ohm meter.
If the water heater does not heat the pressure switch may have failed. The pressure switch can have normally open, normally closed or both types of contacts. The pressure switch can also work off positive or negative pressure depending on the application.
If the water heater does not heat the thermostat may have failed. The thermostat senses and regulates the heat in the water heater. Electric water heaters will usually have two adjustable thermostats,(one for each element) mounted on the outside of the tank behind an access panel. On a gas water heater the thermostat is usually incorporated into the gas valve that is screwed into the lower part of the tank.
If the water heater does not heat the igniter may have failed. The igniter lights the pilot. When the pilot thermocouple or sensor is satisfied the the control will let gas thru to light the main burner.