QA

Question: What Happens When An Expansion Tank Fails

Oftenthe diaphragm dividing the two systems will fail, causing the two systems to become one. When this happens, the expansion tank turns into a “dead leg” that will eventually cause damage and premature failure to your water heater.

How do you know if your expansion tank is bad?

If it makes a dull thud rather than a hollow sound, your tank is full of water and needs repair or replacement. You can also gauge this by feeling the tank, which will be cool where it’s holding air and warm where it’s holding water. If more than half the tank is warm, you have a problem.

What happens when an expansion tank goes bad?

An expansion is meant to handle the thermal expansion of water. If the pressure rises to uncontrollable limits, it can damage joints in supply pipes, valves in plumbing fixtures, and even the water heater. A leaky temperature and pressure relief valve is one sign that your expansion tank has failed.

How often should expansion tank be replaced?

Between five and 10 years is the average lifespan of your tank. If your home’s water pressure matches the air pressure in your expansion tank, you can extend the life of your tank.

How much does it cost to replace expansion tank?

The job of the thermal expansion tank is to absorb the extra water volume so that the excess pressure does not cause undue wear and tear on the water heater and other fixtures in the home. The cost to install a new Thermal expansion tank can range from $279 to $443.

Why does my expansion tank keep failing?

The most common expansion tank problem in a diaphragm tank is losing small amounts of air through the valve. When this occurs, more air needs to be added to the tank. If the tank does not hold its air pressure after you complete this fix or it fills with excess water, you may need to replace the diaphragm.

How do you bleed an expansion tank?

Turn the boiler off, and wait a couple of hours to let the water cool down. Find the shutoff valve and the drain valve on the expansion tank. (The shutoff valve goes into the furnace; the drain valve is on the bottom of the tank.) Close the shutoff valve.

Can an expansion tank explode?

In fact, the tank may explode! Thermal Expansion Can Cause Hot Water Heaters to Explode! A typical hot water heater in an “open” sys- tem has only a temperature and pressure (T&P) valve to prevent a rupture of the hot water heater (figure A). Open systems allow expanding hot water to push into the cold water line.

Will a bad expansion tank cause low water pressure?

Before installing an expansion tank, measure the tank’s air pressure charge. When taken from the box, the air pressure in the expansion tanks will likely be lower than your home’s water pressure.

Do expansion tanks need to be drained?

Draining the expansion tank should be done periodically, usually once or twice a year. We recommend doing this maintenance before the cool season so you don’t have to work with hot water and risk getting burned. Turn off the boiler and close the water supply valve. Allow the tank to cool if necessary.

Why would an expansion tank leak?

And sometimes, as water expands after being heated, it outgrows the space within the tank. When this happens, excess water is immediately sent to the expansion tank to lower pressure levels inside the water heater. But sometimes, due to wear and tear, your expansion tank may start leaking.

Can a bad expansion tank cause high water pressure?

The most common source of high water pressure is actually the municipal water supplier. It’s also possible that you have a faulty expansion tank on your water heater. At the end of the day, the cause of high water pressure is usually something outside of your control.

How long do expansion tanks last?

But expansion tanks can wear out. 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.

Is an expansion tank necessary on a water heater?

While expansion tanks are required by code in most closed-loop water heater systems, they have a reputation for failing. Common expansion tank issues include: Rubber Diaphragm Wear Out.

What’s the purpose of 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.

How do you fix a leaking expansion tank?

The only way to fix this type of leak is by opening the pipe joints and dry any water around the joints. With a cleaning agent and a scratcher pad, preferably plastic, carefully clean the threads on the pipe and joints. Cover the threads of the pipe with plumber’s putty and screw into the joint.

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

$145 – $350, Installed The cost to install a water heater expansion tank ranges from $55 and up for the rare DIY project, to about $350 when a pro adds an expansion tank to a large residential water heater.

What is a waterlogged expansion tank?

When an expansion tank is waterlogged, it’s useless. Water can’t expand. Once that happens, the pressure relief valve on the boiler gets a chance to do its job, and it relieves pressure. This is typically called leaking, but pressure relief valves take offense at that term.

Can a bad expansion tank cause water hammer?

An expansion tank contains a rubber bladder and compressed air that absorb the energy wave as water flows through a pipe. As this device cushions the shock wave, it prevents water hammer. After years of use, the expansion tank can fail as the rubber bladder bursts.