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Water Heater Expansion Tanks

Expansion Tank

Why do I need and expansion tank? Water heaters are fitted with expansion tanks to control thermal expansion created when water is heated by your water heater. They prevent water heater damage and malfunctions in closed loop systems. If water heater failure occurs you can have property damage from water. If your water heaters internal flue collapses your water heater can give off deadly carbon monoxide. Which can poison you and make you very ill or worse you could die. Call All Around Plumbing & Leak Detection Frisco, Plano, McKinney and Allen if you have questions.

What is closed loop system? A closed loop system is any domestic water system that does not have a way for water to flow back towards the meter or city supply. This is done when you or your city places a backflow devise in the domestic system after or in your water meter. These are more common than you might think. Todays newer homes have PRV’s pressure reducing valves which only let water flow one way. Double check valves which do the same thing for your sprinkler systems to keep you from poisoning your self by adding lawn chemicals to your lawn only allow water to flow in one direction also. Some cities place check valves in the water meters to protect the public water supply.

So if you have a closed loop system your water heater will heat the water in the water heater and the water pressure will increase. This is thermal expansion. This not only affects your water heater but all your appliances. When your water heater heats the hot side of the system it also puts pressure on the incoming cold side of the system to. This can lead to all kinds of system failures like faucets, toilets, washer machines, ice makers, dishwashers and any thing else connected to the water supply in your home.

Expansion Tank

Expansion tanks work very simple. Your water heater heats the water and it expands. Your expansion tank has a rubber bladder that is filled with air. This air filled bladder acts like an air cushion that gives the water somewhere to go. Remember water is not compressible. It is that simple but could make a big difference in the life of your plumbing fixtures and your water heater.

Where do I install an expansion tank and what size do I get? Each manufacture has recommendations as to the location and orientation of the expansion tank. The other information you will need when installing an expansion tank for your water heater are? The size of your water heater and the water pressure at residents or place of business. The reason this is important is the more water your water heater holds the greater the volume your expansion tank has to handle. An average 40 gallon water heater when it heats water from 50 degrees to 120 will add about ½ gallon of water from thermal expansion. The reason you need to match the water pressure is so the air bladder function properly in your expansion tank. If the pressure coming in is greater than what your tank is rated for it will fill up and do nothing but fail prematurely.

Expansion Tank Chart

This is nothing new expansion tanks are requires by all plumbing codes where you have a closed loop system. If you have questions call All Around Plumbing & Leak Detection Frisco 972-313-4659.


When was the last time your water heater was changed? Can you afford water damage a water heater makes when the tank starts leaking. Even if your insurance covers it there are things that can’t be replaced at any cost when a water heater goes out. Even if you are covered you still have a deductable. Have you ever been on vacation and came home to a home flooded by a hot water heater? When you’re looking for a new water heater, keep in mind that the money you spend now may well be an investment that pays off in the long run.

Did you know water heaters require a city inspection? Did you also know over 500 water heaters explode in Texas each year, due to improper installations? No wonder the State of Texas requires an inspection on water heaters. Don’t let your families well being and safety depend on any plumber. Statistics provided by TSBPE

Do you know your cities requirements for water heater installations? Lets us help you at All Around Plumbing & Leak Detection in Frisco, Plano, Allen and McKinney TX.

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