Why Isn't My Water Heater Heating Up the Water Despite Being On?

Many homeowners encounter the frustrating issue where their water heater is on but failing to heat the water. This can be a significant inconvenience, especially when you turn on the faucet expecting warm or hot water. In this detailed guide, we aim to help you diagnose and potentially resolve this issue yourself or, if needed, guide you towards professional diagnosis.

Common Faults

One of the most common issues faced with water heaters is faulty gas valves. Bradford White, a well-known manufacturer, has been known to produce faulty gas valves in certain batches. Here’s a step-by-step process to check and replace these components:

Gas Valve Checks

Pilot Check: Ensure that the pilot light is properly ignited and stays lit. If it’s still not lit, there may be an issue with the ignition system. Gas Pressure Check: Verify the gas pressure in your home meets the requirements for proper water heater operation. Too low or too high pressure can impact the performance. Thermocouple Check: The thermocouple is a safety device that detects the presence of the pilot flame. If it’s faulty, it can prevent the gas valve from opening. T-stat Check: The temperature and pressure relief valve (TPR valve) may not be functioning correctly, causing the water heater to not heat properly. Ignition System: If the ignition system doesn’t work, the gas valve won’t operate to heat the water. Check for malfunctioning components such as the igniter or thermocouple.

If you’ve gone through these steps and still find no faults, you may need to consult a professional plumber. Sometimes the problem could be beyond a simple replacement.

Thermal Sensor and Other Components

Another common issue is a faulty thermal sensor. This component, often referred to as a thermister, controls the flow of gas to the burners. If the thermister fails, it may not allow gas to flow, resulting in no heat.

Thermocouple Failure

A significant component in gas water heaters is the thermocouple. It is essential for turning on the gas valve when the pilot light is burning. If the thermocouple fails, it can cause the gas valve to turn off, preventing the water from being heated.

Pilot Light Issues

The pilot light plays a crucial role in gas water heaters but does not actually heat the water itself. It is merely used to ignite the main heating elements. If the pilot light stays lit but there is no hot water, it may be a sign of a problem with the thermocouple or a failure in the control system.

Diagnosing and Resolving the Issue

Given the complex nature of water heaters, many homeowners might not be able to diagnose the issue themselves. Here are a few steps you can take:

Check the Control System: Ensure that the control for the water heater is in the ON position and set to the correct temperature. Check the Pilot Light Input: For a gas water heater with a pilot light that turns on with a switch, make sure the switch is set to the correct position. Replace Faulty Components: If identified, replace any faulty components such as the thermocouple or thermister. This is a simple task that can often resolve the issue. Consider a Professional: If none of the above steps work, seek the help of a professional plumber. They can diagnose more complex issues and ensure proper operation of the water heater. Replacement: If the water heater is older or you cannot find the issue, it might be time to consider replacing it. Modern water heaters are more efficient and come with better safety features.

Conclusion

When your water heater is on but not heating the water, the issue might be simple or complex. By checking these components and following the steps above, you can often resolve the issue. If not, consulting a professional plumber is the best course of action to ensure the safety and efficiency of your water heating system.