Asked by: Magyar Glazovsky
home and garden indoor environmental quality

Is it code to have an expansion tank on water heater?

Last Updated: 28th May, 2020

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An expansion tank is required if a plumbing system is “closed”, which means that the back-flow that normally runs between the house and the main water supply, is blocked. However, when water is heated, it starts to expand, which causes a rise in water pressure. The increased pressure must go somewhere.

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People also ask, do I need an expansion tank on my water heater?

An expansion tank is always highly recommended if you have a 'closed-loop system' caused by any kind of check valve or pressure regulating valve installed on your house's water supply line. A common analogy compares having high water pressure in your home to having high blood pressure.

Beside above, can a pressure tank be used as an expansion tank? An expansion tank usually has a much smaller inlet hole than a pressure tank. But if it has a full open 3/4" port it can work as either an expansion or a pressure tank. The one with the small port will only work as an expansion tank.

In respect to this, where does an expansion tank go on a water heater?

Your expansion tank can be anywhere on your plumbing system and does not need to be installed in close proximity to the water heater. It is most commonly installed using a “T” at the cold inlet to the water heater. But, functionally, it can be installed anywhere on the cold inlet line.

Is an expansion tank required for a water heater in California?

California Plumbing Code Section 608.3 requires an expansion tank to be installed on the water heater when it is a closed system. There are some Water Districts that may not install a check valve or backflow prevention device in every situation.

Related Question Answers

Concha Paunescu

Professional

How much does it cost to install an expansion tank on a water heater?

Water heater expansion tank prices start at around $40 and range up to nearly $200; pricing is largely dependent on the size of the tank. For most residential installations with 40- or 50-gallon water heaters, a simple 2-gallon tank is fine. The tank is quite easy to install with a normal 3/4” threaded connection.

Asma Tchanchikov

Professional

Why do you need an expansion tank on a water heater?

The expansion tank is designed to handle the thermal expansion of water as it heats up in the water heater, preventing excessive water pressure. If water pressure gets to high it can damage valves in plumbing fixtures, joints in supply pipes and the water heater itself.

Nasreen Uguet

Professional

What size expansion tank do I need for a 40 gallon water heater?

Sizing Charts
Static Supply Pressure (psi) Water Heater Size (Gallons)
40 80
40 ST-5 ST-8
60 ST-5 ST-8
80 ST-5 ST-12

Wilfredo Indias

Explainer

How long do water heater expansion tanks last?

The average life of your tank can be anywhere between five and 10 years. You can extend the life of your expansion tank by making sure that your home's water pressure matches the air pressure in your expansion tank. But in some cases, you'll need to replace it.

Earlene Regenthal

Explainer

How do you empty a portable tank?

Using a Crescent Hammer on a Portable Tank (the bottom face of the tank will turn orange) will change the bottom side to automatically eject liquid into whatever is below it, if possible. The tank cannot receive liquid on the bottom side while in this mode.

Martinho Ibias

Explainer

How much pressure should be in a water heater expansion tank?

The recommended water pressure is between 50 and 60 PSI. Thermal Expansion Tanks contain an air bladder which is pressurized with air, and expands and contracts to absorb the expanded water from the water heater. needed. Check the air pressure in the Expansion Tank using a tire gauge.

Quinton Jolita

Pundit

What is an expansion valve on a water heater?

A thermal expansion control valve is essentially a pressure relief valve installed at a water heater to prevent forming excessive pressures in the closed loop of water supply piping and water pressure tank when water is heated at the water heater.

Taneka Borkowsky

Pundit

Can a water heater expansion tank be installed upside down?

2 Answers. In general, the tank can be installed vertically above or below the plumbing, or horizontally. Typically, the tank is only required to be supported when installed in the horizontal position. Most smaller tanks are designed to be supported by the plumbing, when installed in the vertical orientation.

Nacor Trzesnicisk

Pundit

Why does my expansion tank keep filling up?

Expansion Tank. If there is not enough air in the expansion tank, the buildup of pressure will force water out of the safety relief valve located above the boiler. Without enough air in the tank, the tank fills with water. The water expands as it heats up and then escapes through the safety relief valve.

Sambala Lezeta

Pundit

What happens if expansion tank fails?

What Happens if the Expansion / Compression Tank is Not Working? The loss of air cushion in the expansion / compression tank means that at each heating-on cycle the system pressure can be too high, causing the temperature/pressure relief valve to spill.

Dulcelina Shakhlin

Teacher

How do you test an expansion tank?

How to Tell If an Expansion Tank is Working
  1. Tap on the tank. It should be hollow about half way up.
  2. Check the temperature by feeling the top and bottom of the tank. The tank should be warm on the bottom and cool on the top if it is working properly.
  3. Use an air gauge to check the pressure inside the tank.
  4. Check to see if your release valve is spurting water.

Nazariy Marsand

Teacher

How do you replace an expansion tank on a hot water heater?

Just follow the steps below to safely replace your water heater expansion tank.
  1. Step 1 - Identify Your Old Expansion Tank.
  2. Step 2 - Turn Everything Off.
  3. Step 3 - Drain the Water.
  4. Step 4 - Disconnect the Expansion Tank.
  5. Step 5 - Pressurize the Expansion Tank.
  6. Step 6 - Check the Pressure.
  7. Step 7 - Teflon Tape.

Shaila Tovma

Teacher

How do you drain an expansion tank?

How to Drain an Expansion Tank
  1. Step 1 – Shut of the Power and Water Supply. Turn off the water supply to your water heater and also shut off the power supply.
  2. Step 2 – Find the Drain Valve. Find the drain valve on the water heater, the valve is normally at the bottom of the tank.
  3. Step 3 – Connect the Hose.
  4. Step 4 – Open the Drain Valve.

Anny Merayo

Reviewer

How does an expansion tank work on a water heater?

Expansion tanks work by equalizing pressure throughout the system. As hot water enters the heating system, the pressure in the system increases. As pressure increases, the diaphragm in the expansion tank is pushed down. This compresses the air in the tank, creating more space for excess water to enter.

Roumen Autlev

Reviewer

Where should an expansion tank be located?

Contrary to this common practice, the expansion tank can be installed in the cold-water line. It should be located in the largest pipe closest to the incoming main after a pressurereducing valve. Install an isolation valve near the expansion tank so that the tank can be serviced when needed.

Marissa Erraizabal

Reviewer

Do expansion tanks need to be drained?

If the heating boiler expansion tank is heavy (try pushing it up or tapping on it) or if the relief valve is leaking, we probably need to drain the tank and let air return to it. Watch out: don't go pushing the expansion tank all over the place.

Mawdo Gomez Calcerrada

Reviewer

Is expansion tank necessary?

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.

Manoli Yagubov

Supporter

Can expansion tanks go bad?

If you don't have an expansion tank in your system, you really should get one. Expansion tanks will normally wear out after anywhere from 5-10 years. To extend their service life as much as possible, it's vitally important to match your expansion tank's air pressure to your house's water pressure.