7 Easy Steps to Install Water Heater Expansion Tank

Now that you know the right size of the water expansion tank for your system, you should fix one in your building. Luckily, the process does not require special skills. You will only need this guide and a few tools to complete this task.

But first, you will have to head to a store and purchase the tank. You can buy a unit for as low as $40 while larger models go for a few hundred dollars. If you want to use the item with a 40 – 50-gallon heater, choose a 2-gallon model.

You can use a 3/4 threaded connection to fix the expansion tank. For a perfect fit, you will have to place a tee fitting above your water heater. Now here are steps needed to set up a water expansion tank.

How to Install Water Heater Expansion Tank

Step 1: Disconnect the Water and Power Supply

Turn off the water supply to your water heater. If your unit is fixed to a supply line with a shut-off valve, switch off the water flow from the supply line to your building.

If your units run on electric power, switch off the breaker. For a water heater that uses gas, switch off the gas supply. But if you do not know how to perform this task, ring up your local gas provider for assistance.

Step 2: Bring Out Expansion Tank and Accessories

Bring Out Expansion Tank and Accessories

Look for an expansion tank that will suit your unit. You can do this by noting the size of the heater before getting the tank. If you get to the hardware store, you can double-check the size.

Remember to get some plumber’s tape and the tee fitting. You should also add some screws (1 and a half inch) and mounting brackets.

Step 3: Confirm the Water Supply Line for Cold Water

Confirm the Water Supply Line for Cold Water

Head to the line for cold water and find the one that is horizontal to the water heater. You will need this line to make a connection with the unit.

Step 4: Install the Expansion Tank

Install the Expansion Tank

Place the unit above the pipe that supplies cool water to make it close to the heater. Mark a spot on the wall and drill some holes for the mounting pipes. Screw-in the expansion tank and attach the cold water supply line.

Step 5: Attach the Heater Tank

Attach the Heater Tank

Head to the bottom of the connector on the expansion tank and then wrap the spot with plumber’s tape and attach the connector to the tee fitting. Secure this connection with a wrench. Do not make it too tight.

Step 6: Restore the Water and Power Supply to the Heater

Restore the Water and Power Supply to the Heater

Switch on the water supply to your heater. Next, power up your unit by switching on the breakers. If your heater runs on gas, fix the gas supply pipe and turn on the gas.

Step 7: Check the Expansion Tank

Check the Expansion Tank

Test the tank by turning on the faucet. Next, place your hand under the tap to see if the water is hot.

How Do I Know If The Expansion Tank Is Working?

Let’s say the expansion tank keeps water from air with a diaphragm. If It is placed at the end of the water supply line that provides cold water. Gently hit the top and bottom part of the expansion tank.

If the tank sounds hollow, then it’s in perfect condition. But if you hear a thud, this means water has entered into the top chamber because of a damaged diaphragm.

Touch the upper and lower part of the tank to check its temperature. Normally, the lower part should feel warm as it stores heated water from the tank. For the upper part, you should feel a coolness since it maintains cold air.

If the water heater tank has a high pressure while working with a defective expansion tank, water will drip with a TPR valve.

Common Questions about Installing Water Heater Expansion Tank

1. Is It Mandatory By Law To Install A Water Heater Expansion Tank?

Yes, especially if you’re using a closed water supply systems. However, it can be used in buildings with open water supply systems. There is no need to worry about the price as it costs less than $50.

2. Should I Place My Expansion Tank Near the

How Do I Know If The Expansion Tank Is Working

Water Heater?

There is a need to fix an expansion tank near a water heater. You can place it at any spot on the water supply line. Most times, it stays fixed with a T at the cold water inlet that supplies the water heater. However, you can install it on the part of the cold water supply line.

3. What is the Perfect Angle for My Expansion Tank?

You can fix an expansion tank at an angle of your choice. But some manufacturers recommended that you hang it in a vertical position. But any other upright angle is fine.

Bore a hole into the piping and fix the clamps. That way, it aligns with the screw holes of the tank. But this method can be frustrating as it allows you to place it in a single position.

If you purchase an expansion tank, it includes a saddle fitting. This fitting is used to fix the system easily without applying heat or using special tools. It fits the pipe while having features that can connect to the expansion tank.

2 thoughts on “7 Easy Steps to Install Water Heater Expansion Tank”

    • no. (any place is good but with some rules, (reality of your home is not known)
      it only needs to be on the cold line, but way after any ABFV
      the street to home water line has 1 or 2, ABFV, anti backflow valves. (by law)
      this tank expansion must be after any ABFV in the cold lines.
      the exp tank is just a small air tank with a rubber like diaphragm inside.
      one side water other side is 50PSI AIR ,my home has 50PSI, cold line pressure regulator
      due to crazy high city water at 125psi. (in meter box, in lawn)
      so the EXP tank is pumped up to 50 by me. (hand pump or my shop air, and done so before installing the new tank that loves to fail every 3 years.

      in human terms water does not compress, (liquids) and needs to have a place to expand
      and if not present ,huge damage is possible . things crack and now leak.

      the top of the tank expansion has Schroeder valve.
      every 6months I check the pressure with a tire pressure gauge.
      and today this ACT I get water sprayed in my face proof of a FAIL tank, (4th one now in 15 years)

      With tanks like this , how did NASA get to the moon, (Apollo 13:?)



Leave a Comment