Air Management And Air Control In Hydronic Loops
Bladder-type expansion tanks also need good air management and air control to eliminate the air. Air migrates into the hot water boiler loop and air, which leaches out of the water. An air separator is necessary along with an automatic air vent to get rid of air.
It gets rid of air that comes into the hydronic loop and hot water boiler system from the make-up water. Air also comes from separation through heating and cooling. With steel expansion tanks, the air moves into the expansion tank. However, with bladder-type expansion tanks, the air must be eliminated and purged from the hydronic loop system.
The hot water boiler hydronic loop with a bladder-type expansion tank is a completely sealed and hermetic system. Therefore, when the air is introduced into the system by whatever means, it must be eliminated. If not, a hydronic airlock will occur in a hot water hydronic loop itself or a branch hydronic loop.
The airlock will prevent heating by creating a boiler circulation problem. It is thereby essential to have good air management and air control. Especially in hydronic hot water boiler systems which utilize bladder-type expansion tanks.
Expansion Tank Price Factors
Thermal expansion tank cost on a water heater is determined by these factors.
- Who Installs the Tank Most of the cost to install a water heater expansion tank is in the labor. If you can DIY, the savings will be about 75%.
- Type of Tank Support As simple metal or plastic strap to support the tanks weight costs a few dollars. Steel brackets can cost 3-5 times as much as the tank.
- Cost of the Tank There are small cost differences in the prices of the 2-gallon to 5-gallon expansion tanks common to residential installation. Quality is also a factor in tank cost.
- Installation Factors When the water tank is easily accessed and there is room to work, installation charges may be lower than when, for example, the water heater is in a cramped crawlspace or utility closet.
Heating Boiler Expansion Tanks
The photo at page top shows a modern Extrol bladder-type heating system expansion tank. At left over our client’s head is a reddish tan steel heating boiler expansion tank .
In detailed articles listed at the end of this page our information on hot water heating system expansion tanks includes:
How to Drain an Expansion Tank
– Troubleshooting & Repair Guide: Diagnostic Tests for Waterlogged Heating Boiler Expansion Tank
– How to troubleshoot an internal-bladder type expansion tank or How to troubleshoot a traditional bladderless expansion tank or compression tank.
How to diagnose trouble with internal bladder Extrol type expansion tanks – What goes wrong with bladderless expansion tanks – waterlogging & its causes
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Guide To Heating Boiler Expansion Tankshow To Troubleshoot Drain Or Service & Repair The Expansion Tank On Hot Water Heating Systems
- about heating system expansion tanks: their function, size, location, maintenance, and need for draining
InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.
Hot water heating system expansion tank / compression tank installation, troubleshooting, repair:
How to identify, inspect, install, repair, or service heating boiler expansion tanks: here we explain the function of expansion tanks on hot water heating systems.
We discuss what happens if the expansion tank becomes waterlogged, how to drain a waterlogged expansion tank, and what sorts of expansion tanks, like the one shown at page top, should never become waterlogged.
We describe where the expansion tank may be found and we illustrate different sorts of expansion tanks used over the history of hydronic heating in buildings. In this article series we provide a heating system expansion tank / compression tank Troubleshooting & Repair Guide that will address just about any problem traced to this heating system component.
We also provide an ARTICLE INDEX for this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.
Does My Water Heater Need An Expansion Tank
In the Colorado Front Range, the simple answer to the question posed above, is yes. While expansion tanks traditionally have been associated with hot water based home heating, i.e. central boiler systems with hot water baseboards and/or infloor tubing, they are now also standard equipment on all residential water heater installations and replacements.
So whats the big deal? Lets take a closer look at expansion tanks, and learn why they are used with water heaters, as well as with boilers.
Whats An Expansion Tank?
An expansion tank is a relatively small water vessel placed inline in a closed hot water plumbing system to help protect against excessive pressure due to the natural expansion of water as its heated up. The expansion tank provides the extra volume needed in the system during the heating phase. The type of expansion tank used with a water heater is called a potable expansion tank, because its materials are rated for use with domestic drinking water. Standard central heat boiler systems typically use a non-potable rated expansion tank.
Modern expansion tanks vary in size depending on the nature and size of the system theyre installed on, but they are typically much smaller than a standard water heater, on the order of two to four gallons in volume. They can typically be found located in line with cold water piping connected to the water heater or boiler.
Life Without An Expansion Tank?
Annual Maintenance Check
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Installing An Expansion Tank
- As described above, determine your household water pressure with a pressure gauge. If the pressure is above 80 psi, install a pressure reducing valve.
- Check the air pressure on the expansion tank with a tire gauge.
- Adjust the air pressure of the expansion tank to match the maximum household water pressure. Using a hand pump NOT an air compressor.
- Install the tank on the cold water line .
- Open a faucet and allow it to run until you have a steady stream of water. This will remove any trapped air within the tank.
Watch the Video
Renting A Gas Hot Water Tank
If you want to rent a new natural gas water heater and already have a rental tank, contact your current service provider. You may currently be under contract and subject to cancellation fees.
If you own or rent an electric, oil or propane water heater and would like to switch to a natural gas model, confirm that you already have natural gas service and then contact a HVAC Contractor.
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Why You Need An Expansion Tank With A Closed Loop System
The brief answer?
An expansion tank will prevent damage to your water heater and plumbing system.
Heres the more detailed answer…
Like we mentioned in the beginning, a closed system creates a single path for water to flow into your home.
However, when water is heated, its volume expands . When the water volume expands, it puts extra pressure on the tank.
Over time, after continuous expanding and contracting, the tank will weaken .
And thats where an expansion tank comes in.
Excess water flows from the water heater tank to the expansion tank
When you install an expansion tank, the extra water volume created by thermal expansion automatically rushes into the expansion tank, reducing the pressure inside your water heater.
Because it reduces pressure, an expansion tank prolongs the life of your water heater. In fact, some manufacturers may void your water heater warranty if you have a closed plumbing system without an expansion tank.
Now that you know why you need an expansion tank, lets look at how to tell if you have a closed plumbing system.
What Happens Without A Thermal Expansion Tank
The purpose of the thermal expansion tank is to relieve the pressure built when the water expands during heating. Without the extra space supplied for the water expansion, water pressure can build up and cause many problems. One of the most obvious of these problems is the sudden bursting of a pipe, usually caused by ice building up in pipes in the winter.
A lesser-known issue is an undetected, slow leak which causes the deterioration of pipes and fixtures associated with the hot water system throughout the building. This includes everything from showers and faucets to your washing machine and dishwasher. These essential home structures can only handle a certain level of pressure. If a leak goes undetected, the structure can wind up with damages such as a rotting wood frame and growing into toxic mold growth.
The expansion tank is installed on the line going into the water heater and is pressurized to match the hot water systems water pressure. There are two primary categories of thermal expansion tanks for your HVAC system – Compression Type and Bladder Type. The primary difference between the two is that the Bladder Tank contains a membrane isolating the air from the water, and the Compression Tank does not.
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Water Heater Expansion Tanks: What You Should Know
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A water heater expansion tank, also called a thermal expansion tank, is a safety device designed to protect your household plumbing from thermal expansion. The risk of pressure damage from thermal expansion is seldom a concern for tankless water heaters, but if you own a tank-style heater, your plumbing system may be at risk.
When you consider that 50-gallons of cold water will, with the help of thermal expansion, become at least 52-gallons once it’s heated, the additional 2-gallons of water will no longer fit in the water heater’s tank. That’s where a thermal expansion tank comes in.
A Closed Plumbing System
A unit that prevents water from flowing back into the citys water lines once it enters a homes plumbing, is referred to as a closed plumbing system. The Environmental Protection Agency in the United States sets strict standards for public systems under the Safe Drinking Water Act.
The purpose of this closed system is to stop fluid from flowing back through the supply line, which prevents possible contamination from getting into the citys main supply.
The problem with check valves preventing the water from flow back through the supply line, is that pressure builds up. Once it reaches a certain level, there is a risk of damage to the heater and plumbing fixtures.
It is required in Section VIII of the Pressure Vessel Code that heat increase must be addressed in plumbing systems and especially water heater installation. Backflow prevention needs to be in place.
A pressure reducing valve is not considered by the code as a thermal expansion tank. Thermal units with Watt series ET-RA, DETA and ETA all meet the American Society of Mechanical Engineers code and requirements.
Homes with closed systems should consider installing a pressure reducing hot water heater expansion tank. A water expansion tank can be installed to meet these standards.
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Why You Need A Water Heater Expansion Tank And How It Works
Have you heard of a water heater expansion tank? If you havent, youre in the right place to change that.
According to the IBHS, the average lifespan of a water heater is 10 to 20 years. However, this number goes down as most heater failure is due to slow bursts and leaks, at an astonishing 69% from overall issues. Unfortunately, this is quite a big number.
Its essential to understand why an expansion tank is necessary, how it works, and its benefits. Understanding this is the first step to using the utility and power of the device.
This blog post will provide the information you need to make an informed decision about an expansion tank within your homes plumbing. Keep on reading to learn how installing expansion tanks helps and much more.
Purchasing A Gas Hot Water Tank
- Ask your dealer for the water heater tank’s “first hour rating,” which tells you how much hot water the heater will supply during your “peak demand” in the morning, for example, when most family members use the shower.
- Find a tank size that fits your hot-water needs.
- You may also decide to buy or rent a tankless water heater. These heaters are able to heat water on demand and so you will never run out of hot water.
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Technical Reviewers & References
How To Diagnose An Internal Bladder
Newer type heating system expansion tanks that use an internal bladder keep their water and air separated. These tanks should not need frequent service but might need a small additional air charge every few years, as we explained at WATERLOGGED EXPANSION TANK.
But there are at least three possible conditions for which to check an internal bladder type expansion tank for trouble.
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What Happens If The Expansion Tank Is The Wrong Size
Purchasing the right sized thermal expansion tank is important, but if you’re in doubt, it’s best to error on the side of larger than smaller.
An expansion tank that is too large for your system will still be able to safely handle the extra water. However, a tank that’s too small can trigger the temperature and pressure relief valve to open so the excess pressure is relieved.
Reduce Your Water Temperature
You can save energy and reduce the risk of scalds, by lowering your water heater temperature to 54°C . But dont turn your water temperature down too low the water needs to be at least 50°C to prevent the growth of bacteria.
If you’re not sure how hot the water in your tank is, here’s how to test the temperature:
- Don’t use any hot water for several hours.
- Turn on the hot water let it run for a few minutes, then fill a coffee mug.
- Insert a cooking thermometer into the mug. If the temperature is above 54°C, reduce the water heater temperature.
Important: Leaks get worse over time and can cause serious damage. If youre experiencing a leak, contact your rental provider or a HVAC contractor for repairs.
For more safety tips, visit our appliance safety tips for water heating to keep your family safe and your water heater working efficiently.
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Benefits Of Tank Water Heaters
-
Low Initial Cost
Tank water heaters allow you to keep more money in your wallet through their low initial purchase, installation, and maintenance costs.
-
Easy Installation
The uncomplicated design of tank water heaters rarely requires wiring or piping modifications, resulting in a fast, easy installation process. A. O. Smith strongly recommends that youconsult a professional installer.
-
Hot Water Storage Supply
Tank water heaters store a supply of hot water, making it available when you need it most.
Why Is Maintenance Needed For An Expansion Tank
Expansion tank’s are designed with an internal bladder that separates the air and water. Through a process called “diffusion” the bladder will leak air. The leak can often be at a rate of 1 psi a year, which is enough to make a difference after only 12 months.
If the internal bladder ruptures the expansion tank will fill with water and not properly drain. When this happens, you’ll need to purchase another expansion tank since there’s no way to repair the bladder. The average lifespan of a thermal expansion tank is 6-years, provided it was installed correctly.
Checking the Bladder
We’ll give you an easier method, but if you call a professional to inspect your expansion tank, these are the steps he’ll use:
- Turn off the supply of water to your house and relieve the pressure by opening a faucet.
- Remove the cap to the valve stem on expansion tank and attach a tire pressure gauge. The pressure should be above 75 psi.
- If there is no air pressure within the tank, the expansion tank has failed. You will need to replace it with a new one.
- If there is pressure inside the tank, you’ll need to check the water pressure.
- The expansion tank and water pressure should be similar. If its not similar, you’ll need to use a hand pump to add air to the expansion tank.
However, if you’re looking for a quick and easy way to inspect your tank you can simply press the Schrader valve that’s located on the outside of the tank.
Checking the PSI
Watch the Video
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