Exploring Hot Water Heater Parts
Buying, Replacing & Installing Tips
(updated 2018)

Explore hot water heater parts and accessories found on electric and gas water heating appliances for easier order and purchase. With a better understanding of component parts like the gas valve, thermocouple, pilot light, venting system and other; it is much easier to fix the problem and troubleshoot it. By using the instructions found here and combining it with our troubleshooting guide, it becomes easier to repair or replace the broken parts.

Hot water heater parts review will cover mainly the storage gas and electric tank heaters as the most common source of the residential water heating. Use this article for tankless water heater parts.

The main gas and electric water heater parts

As it can be seen in the construction of any water heater, some components are mandatory, whilst others are there for the efficient heating operation and increased safety. Good examples are the heat traps, powered draft hood, hot surface ignitor, flame arrestor, powered anode rod, dry-fire protection... Such a difference will provide longer warranty, higher savings, and comfort, but also a greater initial price.

You can even contact a professional plumber and upgrade your water heater with the quality elements and therefore increase the performance, efficiency, and life.

Storage water tank

Majority of the water storage tank heaters are equipped with the tanks made of carbon steel, while some models, such as Rheem Marathon, utilize a plastic tank, or Westinghouse that uses a storage tank made of the stainless steel. Such a construction automatically eliminates the need for the anode rod, corrosion protection, and frequent maintenance.

Due to the corrosive water action, water heaters equipped with the metal tanks must include the glass/ceramic lining and anode rods.

Gas valve

Gas valveGas valve

Robertshaw, White-Rodgers, and Honeywell are three of the most popular gas control valves and are found on the majority of the gas water heaters. The gas valve is the heart of the water heater as it controls the delivery of the natural or propane gas to the burner and pilot light, and is also a safety device. Since the thermostat is part of the gas control valve, by simply turning the knob you can increase or decrease the temperature of the outgoing hot water.

The above manufacturers have similar elements like the gas control knob, reset button, high water temperature limit safety and temperature dial. More advanced valves are those that have a diagnostic system for troubleshooting and more accurate temperature control.

Heating elements

Heating elementHeating element

Electric heating elements are the source of the heat within electrical appliances and are usually found such as the upper and lower element on tall units or just one on smaller ones. These electric water heater parts can also be found in solar heating systems and heat pumps for the backup heating.

An addition to the electric element protection, some water heaters are equipped with the dry-fire feature which protects the elements if exposed to the air.

Anode rod

Anode rodAnode rod

The anode rod protects the steel metal tank from corrosion, together with the tank's glass or ceramic lining. The element is usually called the sacrificial anode, as it sacrifices itself in order to extend the tank's life. The powered anode is not sacrificial and is found on better models.

How the anode affects the water heater performance, which one is the best and what are the common problems, read this article.

Venting

Power VentPower Vent

The venting system is designed to vent the products of combustion out through the flue baffle and vent pipes, and in some models to draw the fresh air in, needed for proper gas combustion. Based on your preference, home design and construction, the location of the heater and other requirements, you can find different types of venting systems; atmospheric, power, direct and power direct vent, also:

  • Two-pipe closed combustion system that eliminates the problems caused by the insufficient indoor ventilation, while it draws the fresh air from outside the home.
  • Two-pipe or one-pipe atmospheric vent system with the draft hood.
  • Concentric vent system - consisted of two pipes (pipe within the pipe); the larger pipe is used to draw the air in, inside the pipe is designed to direct the gases out. It can be used with or without the electric-powered blower.

Blower

The electric blower is using 110/120 volt electrical system, usually rating 3 amps or less and is equipped with the 6-foot cord.

Dip tube

Dip tubeDip tube

The dip tube is the cold water inlet extension, and some manufacturers like Bradford White, utilize the perforated tube to create the turbulent flow and reduce the scale and sediment buildup, resulting in the maximized hot water output. It is usually made of PEX polymer.


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Gas burner assembly

One of the most important parts found on gas-fired appliances is the gas burner assembly, consisting of several components such as:

Main burner. The advance gas water heaters from the manufacturers such as Rheem, AO Smith, and Bradford White, utilize the Eco-friendly burners and are able to reduce the NOx emissions by one third when compared to the standard burners.

Orifice. Burner orifice (should be replaced when converting the water heater from natural to LP gas, or vice versa).

Manifold tube. Pilot burner/pilot light with the pilot tube and orifice. On water heaters with the pilot light, pilot burner remains ON once it is manually lit. It is used to ignite the gas. Some manufacturers utilize the hot surface or electrodes instead of the pilot flame.

Igniter like piezoelectric or hot surface is used to light the gas.

Thermocouple. The thermocouple is the safety part used to send the signal from the pilot light to the gas control valve to allow or stop the gas delivery. The small electrical current is generated which is enough to signal if the flame is present or not. A thermopile does the same thing as the thermocouple - converting heat into the electrical energy, but is composed of a few thermocouples connected into series, increasing the unit’s ability to produce electricity.

ECO

ECO or Energy Cut Off is the metal tube (temperature probe) which is mounted onto the back of the gas valve and immersed inside the water tank. It acts as the temperature high limit.

TCO

TCO or Thermal Cut Off Switch is a resettable thermal switch, constructed to shut off the gas supply if the temperature of products of combustion is too high.

Thermostats

Mechanical type thermostats are used on standard residential water heaters. Thermostats are usually factory set to 120 F to prevent scalding water, and they operate with the certain tolerance.

FVIR and flame arrestor

Fire-proof flame arrestor, built in the water heater base, is part of FVIR or Flammable Vapor Ignition Resistant technology that deals with the accidental or unintended ignition of flammable vapors. It is made of the stainless steel.

TPR valve

TPR valveTPR valve

TPR valve or temperature and pressure relief valve is used to protect the system from the excessive hot water pressure. It is usually combined with the discharge pipe to an adequate drain.


Drain valve

Drain valveDrain valve

Water heater drain valves are found on every water heater and are made of plastic or brass. The main purpose of the drain valve is for draining, flushing, and maintenance.

The recommendation is to use one made of brass as they are more durable with better quality while plastic drain valves are easy to damage especially around the threads making it more likely to leak.

Air pressure switch

Air pressure switch is used on all gas water heaters that are using the electric-powered blower for venting products of combustion. It is used for all power vent and power direct vent heaters to verify that operational conditions are met.

Insulation

Different foam thicknesses around the tank will provide more or fewer savings in energy and heat waste, efficiency and performance improvement. This is why some manufacturers are designing hot water heaters with 2" or 3" inch high-quality insulation, while with the low efficient heaters it is recommended to use an insulation blanket.

Timer

Electric TimerElectric Timer

Great way to reduce the energy consumption and save money is to install the electric water heater timer. Water heater timer is designed with one goal only; to turn the water heating off during the periods when hot water is not used.


Mixing valves

Hot water mixing valves are used in residential water heating; for showering, bathing or hand-washing, to reduce the point-of-use temperature by mixing hot and cold water in the branch water line.

Recirculating pumps

How to get hot water faster with the recirculating pumps – Importance of installing hot water circulating pumps.

Does it take too long to get hot water in the kitchen and bathroom sink, or a shower? Are you tired of getting the surge of cold water while expecting a nice hot shower?

How to order repair parts

What you should know when ordering gas or electric water heater parts:

  • Have the complete part number and description ready.
  • Have the water heater model, series and serial number ready.

Note: If any part of the water heater has been exposed to moisture, you should contact a qualified service technician for the repair. If the water heater has been subjected to the flood conditions or any of its component parts including gas controls, main burner, pilot light submerged in water, an entire water heater should be replaced.

Related articles

Drain valve - How to replace
Heating elements - Buying guide, testing and replacing
Thermostats - how to set, problems, testing and replacing
How to replace an anode rod
How to replace a thermocouple
Replacing a TPR valve
Dip tube - how does it work and replacing tips
Gas valve
Mixing valve

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