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How To Replace A Hot Water Heater Expansion Tank

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If the water from your shower feels too hot or you notice a leak near your hot water heater, it may be time to replace the hot water heater expansion tank, which is commonly located next to the water heater. The expansion tank catches and prevents hot water from backflowing into the city's water system.

It is essential to replace the expansion tank as soon as possible, which can be done by a DIY enthusiast with no plumbing experience. Here are some tips to replace a hot water heater expansion tank.

Prepare to Work

For this project, you need:

  • work gloves
  • bucket
  • garden hose
  • plumber's tape
  • channel locks or pliers
  • bicycle pump
  • water pressure gauge
  • replacement pressure tank

Place a bucket under the area that leaks. Turn off the power to an electric hot water from the breaker, or blow out the pilot on a gas hot water heater. Let the hot water heater cool for about an hour.

Drain the Tank

Attach a hose to the drain valve on the bottom of the water heater, rotate the valve counter clockwise, and empty half the water from the tank outside, in a tub, or through a floor drain.

Turn the drain valve to the right to close it. Open a sink tap to relieve water pressure from the pipes. Let the faucet stay open a minute or two, then shut the tap off.

Replace the Old Pressure Tank

Remove the old pressure tank; loosening the hardware with channel locks or pliers. Use the old tank as a guide to buy a replacement. The new tank should have the same maximum pressure and temperature ratings as the old one.

Connect a water pressure gauge to an exterior faucet. Rotate the faucet until you can no longer turn it. Check the pressure on the gauge, which should read 0. Close the outside tap.

Connect the bicycle tire pump on the Shrader valve on the bottom of the tank. Fill the new tank to the required amount of pressure according to directions.

Wrap plumber's tape around the male connections on the new tank. Skip wrapping tape around the first two connection threads, so tape won't get into the system. Set the new tank in place, and tighten connections.

Turn the and water supply on, and check connections for leaks. If connections are leaking, tighten them. Open a tap to allow water to flow through the hot water heater, and check for leaks again.

Restore power or gas to the hot water heater. Check the system for leaks again after the hot water heater heats. If you don't trust your skill or the hot water heater still leaks, contact a plumber like Cleary Plumbing .