What is a Precharged water system tank?

Asked by: Michael Bland

The main advantage of pressure tanks vs an air-over-water tank is that they can hold the same amount of water in a smaller unit. Pressure tanks are often referred to as pre-charged tanks or bladder tanks because they have a vinyl bladder holding the water with pressurized air around it.

Are expansion tanks Precharged?

Expansion tanks are pre-charged with a 40 PSI air charge. If the inlet water pressure is higher than 40 PSI,the expansion tank’s air pressure must be adjusted to match that pressure but must not be higher than 80 PSI.

What is a pre-charged expansion tank?

Pre-charged Expansion Tanks contain either a bladder or a diaphragm to separate the air charge from the system water. Tanks are design to absorb the expansion forces of heating/cooling system water while maintaining proper system pressurization under varying operating conditions.

What is the difference between a bladder tank and a diaphragm tank?

A bladder tank contains a vinyl tank inside it. A bladder tank can be replaced as and when required. On the other hand, a diaphragm tank contains a rubber flat diaphragm, a butyl tank or a vinyl tank that is mounted on it. The diaphragm is kept attached in the internal area of the tank.

How do you install a precharged expansion tank?

Open the drain or open the valve. And read the pressure on the gauge. Once the pressure is determined in this case let's assume it's 55 psi.

How do pre charged pressure tanks work?

When you turn on the water in your home, the compressed air forces water out of the tank. Once the water level drops to a certain level and the air pressure in the tank hits a pre-set minimum (typically 30 to 40 psi), the pump turns back on and replenishes the tank.

What is the difference between an expansion tank and a pressure tank?

The biggest difference between pressure tanks and expansion tanks is in where they’re used. Expansion tanks are installed above a water heater and help to protect it when hot water expands. Pressure tanks are installed near your well pump and help to protect and extend its lifespan.

What pressure should my expansion tank be set at?

between 50 and 60 PSI

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.

Where should the expansion tank be installed?

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.

How long do expansion tanks last?

between five and 10 years

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.

Will an expansion tank increase water pressure?

The expansion tank contains air, which is highly compressible. Expanding water from the water heater can flow into the expansion tank, where the air compresses, making room for the increased volume of water. Water pressure in the system doesn’t increase significantly.

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.

Why install 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.

What happens if you don’t have an expansion tank on water heater?

In a “closed” plumbing system, water can’t flow back into the city water lines once it enters your home’s plumbing. Now that might not seem so bad but if you don’t have an expansion tank, a closed system doesn’t give expanded water any route for escape, causing damage to your home’s water heater and plumbing.

What size expansion tank do I need for a 50 gallon water heater?

For a 50-gallon water heater, you require a 2-gallon expansion tank. Depending on how high your water pressure is, however, you may need to go up a size to a 4.5-gallon expansion tank.

What size expansion tank do I need for a 75 gallon water heater?

Enter the appropriate information in the boxes below..

What size pressure tank do I need for my home?

General Rule of Thumb for Sizing a Pressure Tank



Generally, as a rule of thumb, one can follow these guidelines when sizing a pressure tank: 0-10 GPM: 1 gallon of drawdown per 1 GPM of flow. 10-20 GPM: 1.5 gallons of drawdown per 1 GPM of flow. 20 GPM+: 2 gallons of drawdown per 1 GPM of flow.

Do I need an expansion tank for my electric water heater?

If your home has a “closed” plumbing system, then yes, you’ll need an expansion tank. You see, homes have either an open or a closed plumbing system. A closed plumbing system prevents water from flowing in the reverse direction (i.e., water won’t flow back into city lines once it enters your home’s pipes).

Can expansion tank cause low water pressure?

To reduce pollution, most plumbing systems are now “closed.” Today, when cold water in your water heater is heated and expands, it dramatically increases the pressure in your home’s pipes which can damage your home’s plumbing system. Thermal expansion happens in your car, too.

How do I know if my expansion tank is working?

Finally, testing your Thermal Expansion Tank is important and should be tested once a year when you flush your water heater. If your Thermal Expansion Tank is hanging from a pipe, you would push the Schrader Valve (air valve), located on the bottom of the tank, if the air is released then the tank is working properly.

Do expansion tanks need to be drained?

Water will get inside of the system, of course, which means that you are going to need to drain expansion tank to make sure that the pressure that the tank absorbs is always at an optimum. This task shouldn’t take very long, and should be done a couple of times a year by you or a professional.

How much does it cost to replace an expansion tank?

$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.

Why would an expansion tank leak?

An expansion tank is a small tank that protects closed and domestic water heating systems from excessive pressure. The changes in pressure inside the expansion tank can bring about the degradation of the water heating system and cause leaks.

How do you fix a leaking expansion tank?

If the leak is located on the expansion tank itself, you will need to call in a professional plumber to replace the tank. If the leak is coming from the pipe or pipe fitting at the top of the tank, you will likely only need to tighten the fitting with a wrench.

What causes an expansion valve to fail?

What causes a TXV valve to go bad? Thermal expansion valves work under extremely high pressure and temperatures that fluctuate up and down. The valve’s parts are bound to wear down over time from the fluctuations. A TXV valve can fail if it’s too open and overfeeding or too closed (underfeeding).

Can you unclog an expansion valve?

Opening of the valve should be relatively quick. Even holding he bulb in your hand should provide enough heat to open the valve. Next, place the TXV bulb into cold water. This should cause the expansion valve to close reducing the amount of refrigerant to pass thought the TXV into the coil.

How do I know if my expansion valve is clogged?

4 Symptoms of a Bad A/C Expansion Valve (& Replacement Cost)

1. #1 – Poor Air Conditioning Performance.
2. #2 – Inconsistent Airflow From Vents.
3. #3 – Air Conditioning Constantly Running.
4. #4 – Frost Forming on A/C Compressor or Vents.