Water Heater Failure
Signs, Causes and Solutions

Explore early water heater failure signs and causes and what you can do to prevent and protect the heating system. 

Extend the life of the water heater and avoid cold showers by eliminating the problems related to the thermal expansion, undersized tank, sediment deposits, and deteriorated anode rod.

A water heater failure and unit replacement can be easily avoided if you identify the early signs of the problem. The symptoms or signs, potential issues and how to troubleshoot them are described below. Some of these problems are an easy fix some require more time, knowledge and the right tools.

Note: For the proper, fast and safe repair of the broken water heater recommendation is to contact a professional plumber.

The most common causes of the premature water heater failure are:

  • Thermal expansion
  • Improper sizing
  • Bad cathodic protection
  • Heavy mineral deposits 

Thermal expansion

Thermal expansion occurs when the temperature of the water inside the water heating system is rising, so water will expand and volume increase. The extremely high temperature and pressure values inside the water heater tank are the primary cause of the leaky TPR valve, bulging heater, and deformations.

Water tank heaters are designed to withstand an internal pressure of up to 300 psi, but if the pressure exceeds this value, bulging will occur followed by the deformation of the tank and its elements (such as nipples, flue tube) or rupture of the welds and joints.

The only fix for the extremely high thermal expansion is the installation of the correctly sized expansion tank, which will maintain constant and safe water pressure. Such small expansion vessels are mandatory for heaters installed in the closed systems. If not, the manufacturer has the right to void the warranty. To avoid the failure, make sure that the supply water pressure does not exceed 60 psi, otherwise, a pressure reducing valve is recommended.

Undersized water heater

The improperly sized water heater is usually the major cause of the heavy condensation and rusting, including premature heater failure. Condensation is normal, but heavy condensation is not. An extensive condensation and acidic condensate that is dripping on the burner, and other elements will cause the corrosion, affecting the performance and shortening the life.

The fix for this problem is to size the unit properly, which will include the right storage capacity and recovery rate. Read this guide to learn how properly to size a water heater.

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Cathodic protection

Every water tank heater, either gas-powered or electric, is equipped with the anode rod. The anode is used to protect the metal tank from the aggressive water heater conditions or corrosive action.

The current derived from this rod is making the inner metal tank surface cathodic, therefore, protecting it from the chemical reaction with water ions and rusting.

If the rod is depleted or removed, the steel tank won't have such protection (actually only the glass lining), and it will eventually corrode.

The regular maintenance which will include the visual inspection and replacement is recommended.

Mineral buildup

Hard water, which is found in almost any region, can cause heavy mineral deposits and sediment or limescale buildup on the heater's components.

Most of the time water softeners are recommended to deal with such a problem, but it should be considered its detrimental effect on the anode rods. Due to the rapid anode consumption, the rod should be inspected more often.

Limescale and mineral deposits on the heater's components and its bottom will definitely clog the narrow water passages and reduce the heat transfer and its efficiency.

Instead of using the water softeners it is recommended to perform deliming and flushing procedure on a regular base to remove the mineral buildup and further water heater failure.

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