Description Reviews (0) Description. Figure 3 shows several acceptable placements of the tank. The air pressure in the tank increases and so does the water pressure in the system. Expansion tanks (aka Thermal Expansion Tanks) are essentially safety devices to help you minimize the risk of damage to your hot water tank.They are an "add on" to your existing hot water heater and are often installed on the water supply pipe to the water heater.Normally this is on the wall next to or very close by your hot water tank. Pa = correct air side pressure (psi) How an Expansion Tank Works . This is when you will appreciate having a ball valve that can isolate the tank from the remainder of the system. It is simply a closed tank with a connection to the chilled water system. The concept is to add sufficient fluid to the tank during loop pressurization so that the diaphragm is not completely expanded against the inside of the tank until all fluid in the system is at the lowest possible temperature. Just follow the steps below to safely replace your water heater expansion tank. Figure 4 Mounting diaphragm type expansion tank. 8. Taller piping systems require higher air pressures to prevent partial compression of the diaphragm before the fluid is heated. Think of the air in the tank as a spring. Related Topics . Some tanks fail when a leak develops in the diaphragm. With the right tools and this guide you will be able to replace the expansion tank on your water heater without calling a professional plumber. I have all of the details worked out except for an expansion/head tank. Do not assume compatibility: Be sure the expansion tank you select is compatible with the fluid used in the system. Water expands as it heats up, and without an expansion tank attached to the water heater, a closed plumbing system can experience damage from this thermal expansion. This can be a problem in any closed system where water is heated. For example: if the top of the piping circuit was 25 feet above the expansion tank connection and assuming the system is filled with water, the correct air side pressure in the tank would be: Get a low-pressure tire gauge with a scale of 0-30 psi and a bicycle pump or small air compressor. Your email address will not be published. Figure 4 illustrates the differences. 7. Radiant Floor Heating Installation Manuals, Installing Controls for Radiantec Heating Systems, Installing Pex Tubing for Concrete Slab Underfloor Heating, Solar Domestic Water Heater Installation Manual, Solar Domestic Water Heater Owners Manual. Do not create multiple connection points: It is fine to use two or more expansion tanks with a combined volume of a single larger tank. An expansion tank can easily be recognized by the neck and cap used. IMPORTANT PLEASE READ THESE INSTRUCTIONS CAREFULLY BEFORE INSTALLING OR USING YOUR ACCUMULATOR / EXPANSION TANK. tank is hanging from the ceiling, replace it with a No. If an expansion tank is overfilled it will discharge coolant when the system is at operating temperature. Since the tank is under pressure it will require a pressure rated cap and neck, (Shown right). As the system’s water expands this “spring” gets compressed. | Site Designed by Axis Web Design, For more information call 1 800-451-7593 | FAX 802-626-8045, Site Map | Terms & Conditions | Privacy Policy. However, if the tank is properly sized, the increase in system pressure is not enough to cause the pressure relief valve to open, even when all the water in the system reaches its maximum temperature. 1 way out in system. If the tank’s diaphragm is fully expanded against the steel shell at a fluid temperature of perhaps 45F, any further cooling of the fluid could cause negative pressure in the system and possible inflow of air from a float-type vent. A closed plumbing system prevents water from flowing in the reverse direction (i.e., water won’t flow back into city lines once it enters your home’s pipes). I am assuming this would weaken the argument for placing the expansion tank on the discharge side since there is hardly any hammer effect in my opinion. All Rights Reserved. Absorbs increased water volume when water is heated. When water is heated the space required for each molecule increases. If you have more questions about water heater expansion tanks, please give … Doing so reduces changes in system pressure as the fluid temperature varies. 2. To prevent such a result, closed-loop hydronic systems are equipped with an expansion tank. The working pressure inside the water heater tank is approximately 150 PSI, and the tanks are tested to withstand a pressure of 300 PSI. RE: 2 expansion tanks in closed system. To safeguard against a possible dangerous malfunction of the expansion tank, review the installation instructions before At left over our client's head is a reddish tan steel heating boiler expansion tank (or compression tank in some texts). PURPOSE OF EXPANSION TANKS When water is heated it expands. Nearly seven decades after inventing the first diaphragm expansion tank, Amtrol’s lineup now includes specialty models engineered for modern, high-efficiency systems. All Rights Reserved. The closed tank has extra space that is filled with air, when the temperature in the system is cold. Controls thermal water expansion in closed hydronic heating systems. Replacing your water heater expansion tank by yourself can save you a lot of money and time. Both water heaters and boilers for home heating systems can be prone to this kind of damage unless measures are taken to prevent it. Do Pump Away: A detail that was once understood and respected in the hydronics industry, but slowly faded in priority against other packaging or installation “conveniences,” is to connect the expansion tank into a hydronic piping circuit near the inlet of the circulator. As the temperature Order a 2 gallon expansion tank with a 3/4″ or 1″ Plumbing Mechanical Package. The five psi margin prevents the relief valve from “dribbling” as the pressure approaches its rated opening pressure. If the house has a closed plumbing supply, meaning there is a check valve or backflow preventer that prohibits the release of water pressure building back into the water main. Figure 6 Strapping system secures tank shell. Some expansion tank manufacturers offer strapping kits or other hardware to properly support the tank shell. The increase in volume for a 50 per cent solution of propylene glycol heated from 60F to 180F is about 4.5 per cent. The pressure in the tank is adjusted by means of the air valve in the closed end. The expansion tanks are designed to receive the increased water volume and therefore reduce the pressure inside the tank. If ordering the Plumbing Mechanical … The expansion tank uses compressed air to maintain system … Depending on where you live, an expansion tank might be required by the city regardless of the water pressure in order to pass plumbing inspections – such as you would get upon the installation of a new water heater. Without this valve you might have to drain several gallons of fluid from the system just to unscrew the failed tank and screw in a new one. In order to achieve this, a “closed” pressurized system had to be created. An expansion tank will work no matter where it is installed in the system. It also enhances the ability of air vents to eject air from the system. Diaphragm expansion tanks can be sized using charts or software. Order a 4.4 gallon expansion tank with 1 1/4″ or 1 1/2″ Plumbing Mechanical Package. An expansion tank can also be used as a fill point for the system. Sizing Hot Water Expansion Tanks - Hot water expansion volume in open, closed and diaphragm tanks; Sizing of Diaphragm Expansion Tanks - Low temperature diaphragm expansion tank sizing - calculate tank volume and acceptance volume