What To Know About Your Expansion Tank This Season

When winter is just around the corner, it’s time to start thinking about what kind of heating system you’re going to use. There are many different heating systems but many of them use an expansion tank.

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Water heaters and boilers alike use an expansion tank. These are both similar as they are used to heat water which will heat your home in one way or another. So learning about an expansion tank can be useful.

What Is An Expansion Tank?

An expansion tank is a tank made to relieve pressure in certain types of heating systems. It monitors the pressure and ensures that constant pressure is present yet not too much pressure damages the pipes.

Without the expansion tank, the pipes could easily burst, requiring major repairs, making a mess, and even injuring people severely. So an expansion tank is important with a boiler as a safety measure.

How Does An Expansion Tank Work? 

Expansion tanks equalize pressure throughout the heating system. It is a small tank that is divided into two sections. One side is connected to the pipes of the heating system. This section contains water.

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Image from Flickr.

The other side is empty, or at least, it simply contains pressurized air. The way it works is that the hot water enters the heating system, and the pressure increases. When this happens, the air is compressed.

So more space is created for the excess water, relieving pressure. This is how the boiler expansion tank prevents damages to the pipes which prevent accidents in the heating system, and why an expansion tank is necessary.

Considerations For Your Expansion Tank

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There are a few things to take into consideration when buying a new expansion tank. While most of the time, a professional will take care of everything, there are occasions where you need to find out a few things first. 

Size Of Expansion Tank 

The size of the expansion tank is probably going to be your first consideration. Now, your water heater will definitely let you know the size of the expansion tank that you need, so check that to find out the size.

But in general, it’s actually the psi that matters. Take the psi recommended and divide it by 20 to get a good idea of the size of the water tank that you need. You can do the same for water heater capacity as well. 

Cost Of Expansion Tank 

Expansion tanks can cost anywhere from $50 to around $200. Of course, the size of the expansion tank affects the price but knowing that you won’t pay more than a couple of hundred dollars is a load off.

That said, if you are replacing your tank every couple of years, the cost over time can add up. If this happens, consider switching to a different heating system with a larger upfront cost that will make it worth it. 

Related: How Much Does A New Boiler Cost In 2021?

Expansion Tank Maintenance 

Expansion tanks can be checked by a professional once a year when your heating system is checked. But you can do self-maintenance really easily as often as you like but at least every few months when in use.

All you have to do is touch the tank. The top of the tank should be warm but not scalding hot. The bottom should be only slightly warm or room temperature. If the entire tank is warm, then call a professional. 

How To Install An Expansion Tank

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About 90% of the time, you will install an expansion tank when you install the water heater. You can install the expansion tank separately, but when you do, it can be difficult to find room for the expansion tank. 

That’s why a lot of people tend to do both at the same time as you will get an expansion tank that is a set with the water heater. This yields the best results so let’s go through this process of installing a water heater. 

Step 1: Get Everything Ready

The first thing you’ll do is go to the circuit breaker and turn the power off, not the water, to the water heater. Use a voltage tester to make sure the power is off then break off the connection to the wires.

Let the water in a faucet run until the water is cold. Then attach a hose to the tank and turn a faucet and let the water drain from the tank. It shouldn’t take long, just make sure it’s draining where you want it to.

Step 2: Remove The Tank

Now that the tank is empty, you can remove the discharge pipe from the temperature and pressure relief valve. You can also disconnect the water from the tank at this point. The tank should be free of anything connected. 

When this happens, you can remove the tank. You shouldn’t move the tank alone nor could you as it will be too heavy. So instead, have someone help you remove it and properly discard it at the appropriate disposal service. 

Step 3: Get New Tank Ready

Put the new water heater in a drain pan. Then, take the temperature and pressure relief valve that came with the new water heater and twist it into place. It should be very easy to do this so if it isn’t, you may be doing it wrong.

Just don’t reuse the old valve. This valve is used to open if the pressure becomes too much in the tank. Now, position the discharge pipe from the temperature and pressure relief valve toward the floor or drain and cut it. 

Step 4: Install Fittings

Use a flexible hose kit and plumbers tape to attach the hoses. Then secure dielectric fittings to reduce corrosion between two different metals. Finally, secure the fitting to the hose and then hold the hose up to the pipe. 

If you don’t have any experience with plumbing then you probably shouldn’t use this as a first attempt. Hire a professional if you are lost at this point because it will only get more complicated from here. 

Step 5: Install Further Fittings

Slide the compression nut and ring onto the pipe. Then push the pipe into the fitting and tighten the nut. Use seismic straps 6 inches from the top of the water heater and 18 inches from the bottom.

Secure one end of the strap to the stud with a socket and ratchet. If blocks cover the studs, use a masonry bit to create a pilot hole. Wrap the strap around the water heater and adjust the size, securing the adjustable bracket on the opposite side. Pull the strap tight and repeat the process on the lower strap.

Step 6: Check Leaks And Fill

Slowly turn on the water supply, having someone check everywhere for leaks as you do. If you don’t see any leaks then you’re good to finish filling the new tank. If there are leaks, turn off the water and find the problem.  

When water runs from the bathroom faucet then the tank is full. Let it run for three to five minutes to get rid of any debris or chemicals in the tank. Then you are ready to use the tank after connecting electricity. 

Step 7: Connect Electric

Remove the junction box cover and attach the ground wire to the green ground screw. Twist the wires together and secure them with electric plugs. Replace the junction box cover and turn the power on.

This should work. If it does not, then turn the power back off and check the connections. Then, set the temperature to 120 degrees Fahrenheit. It will take a while for the heater to get the water ready the first time. 

Step 8: Check Heater

After the heater has been heating for a few hours, you should make sure that everything is working correctly and there are no leaks. Turn the psi to 80 or lower, depending on how big the tank is and how much you need.

If you have any problems, always call a professional as soon as you can. Turn the power and water off to the heater and wait for the plumber to arrive so they can help you with the problem at hand. 

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Do I Have An Expansion Tank?

If you don’t even know if you have an expansion tank, this is easy to check. Go to your hot water heater or boiler and check around it. Most likely, there will be a small, two to four-gallon tank somewhere nearby. 

This is the expansion tank. If it ever needs to be replaced, replace it with the same size for best results. You can check the size by looking at the sticker or stamp on the expansion tank. If all else fails, take the old tank in with you. 

This can work well anyway in case the tank is a specific kind of tank that is difficult to replace. So detach it carefully after the water and heat is shut off from it and then you can take it in to have it looked at.