2 Reasons Why You Need A Water Heater Expansion Tank

Residential hot water heater expansion tank

Look at your water heater. Above your tank-style water heater, you may see a little metal tank. It resembles a small propane tank. This is your water heater expansion tank. What's it for?

The shortest and simplest explanation regarding the purpose of an expansion tank is this: Against the possibility of excessive pressure build-up in your home’s water heater tank, it offers protection. As the water heater heats up, the contents (water) expand.

Here's an example: Let's say you have a water heater tank full of 50 gallons of cold water. When it heats up, it expands to 52 gallons. Where will that excess water go? The excess water can be taken on by the expansion tank. Resulting from the incoming water supply, extra pressure can also be absorbed by this tank.

So there you go – the two reasons you need a water heater expansion tank:

  • Take on excess water.
  • Absorb extra pressure.

But what happens if you don't have an expansion tank?

Homes Without Expansion Tanks

If an expansion tank isn't present, the home’s water main will likely have a check valve. Depending on the house’s plumbing design, the absence of an expansion tank may cause excessive pressure buildup, but possibly not.

If water is dripping from the water heater’s relief valve, or if you've noticed a rapid deterioration of plumbing fixture washers, adding an expansion tank is probably a good idea. Compared to the price you'll pay for your home’s plumbing system repairs, an expansion tank could be a low-cost solution.

What Could Happen?

If you have a faulty expansion tank or no expansion tank at all, what's the worst that could happen? Your home could be damaged by the water heater’s excess pressure. The water heater itself and fittings could be damaged, and water could overflow damaging anything in its path. The water heater may possibly explode if the pressure release valve is also damaged.

What About Tankless Water Heaters?

Is an expansion tank necessary for a tankless water heater? Very simply… No. Only when hot water is demanded does a tankless water heater actually heat it. Hot water is not stored in this system. Talk to a professional to decide which system works best for your situation – a tankless water heater or the standard, traditional tank-style water heater (with an expansion tank).

Water Heating Direct Can Help Answer Questions about Expansion Tanks and More

At Water Heating Direct, we understand that making the decision to purchase a new water heater is just the beginning. From there you will require a selection of high-quality models from which to choose, water heater accessories, good advice, and possibly technical assistance. We can help with all of those.

We offer a selection of premier water heating equipment. Witness, for yourself, how we beat the competition with our service plans, specials, and honest pricing. We also have a page on our website that allows you to download technical documents. What's more, our specially designated applications/engineering team can assist you with inquiries and issues.

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