However, if you have a traditional tank-style water heater , you will most definitely need to consider if an expansion tank is needed. First, you must understand how your water heater works. When water is heated inside your water heater, it expands.
This process is called thermal expansion and it can cause strain on your plumbing system. The way that it works is this: if your water heater holds 50 gallons of cold water, it will expand to about 52 gallons when it is heated. If the extra volume has nowhere to go it pushes on the walls of your plumbing. You can think of this process as bending a paper clip; with enough bending, the paper clip will break.
Your water heater is this paper clip; given enough pressure from the expanding and contraction, the tank itself can start leaking or possibly even burst. Unfortunately, many homes have closed water supply systems, wherein the water supply has a one-way valve. Many cities where homes have closed systems require the home owners to invest in an expansion tank.
As a matter of fact, the manufacturer of your water heater may even void your warranty if you do not have an expansion tank with your closed system. There are ways to test this and determine if you have a closed or open water supply system, but the process may be difficult because the backflow prevention devices tend to vary in appearance. However, you can always contract a plumber to perform this particular task.
Then where does the expansion tank come into play? Your expansion tank can help you to save your system. The expansion tank serves to take on the extra volume as well as any fluctuations in the incoming water supply pressure. If, over time, the bladder begins to leak some air, a Schrader valve, identical to the fill valve found on bicycle and car tires, can be used to add more air. Expansion tanks are considerably smaller than water heaters, usually holding about two gallons in residential systems, although tank sizes vary in relation to the water volume of the hot water supply system they serve.
The design pressure for which a tank is rated is marked on a label on the tank, commonly pounds per square inch PSI for a residential tank. InterNACHI inspectors should check that tanks are positioned high enough above the water heater that water will easily drain back down into the water heater tank.
It is best positioned near the water heater and may be installed vertically, either above or below the horizontal supply pipe, but can also be positioned horizontally. Horizontally-hung tanks will need additional support to reduce the stress on the copper piping. The expansion tank should be inspected for proper location and support, corrosion and leakage.
Although many jurisdictions now require an expansion tank to be installed at the same time that a water heater is installed, an expansion tank has not always been required in the past and may still not be required in some regions.
TPR valves are capable of reducing water pressure at a rate greater than the capacity of the water heater to raise it, thus eliminating the possibility that water will become superheated greater than degrees and pose a serious threat. The importance of this valve cannot be overstated, and it is crucial that it is examined periodically for rust or corrosion, and the release lever should be exercised monthly by the homeowner, not by the inspector. Pressure will continue to build in the water heater tank as water temperature rises past the boiling point and water becomes superheated.
Eventually, pressure in the tank will exceed the ability of the weakest part of the water heater to contain it and the tank will rupture, exposing the superheated water to air and causing an instantaneous and explosive expansion of steam. Posted by Ohio Heating. Why are people installing water heater expansion tanks? An expansion tank is installed on the water supply pipe to the water heater in order to deal with thermal expansion of water as it heats up in your tank.
This is to prevent water pressure from getting too high. If water pressure gets too high it can damage valves in plumbing fixtures, the joints in your supply pipes and even damage the tank itself. The tank serves as an overflow receptacle by absorbing excess water volume that is created when water is heated.
Your water heater creates extra water volume every time it heats water. The extra volume creates excess pressure in the plumbing system. Over time, this can damage your heater and your system. In the past, the expanding water tanks could push some water back out of the house into the public water main.
The water main could then absorb the pressure. This no longer works as a solution. Check valves, a one-way valve that prevents back flow of water, are now installed on all connections to public water supplies.
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