How To Clean A Heating Oil Tank (Easy Step By Step)

An oil tank should function normally for several years without needing any regular maintenance. However, a heating oil tank does accumulate sludge over time. This sludge needs to be cleaned out about every 3 years, otherwise, it can clog fuel lines and fuel filters.

So below we’ll look at the steps needed to clean a heating oil tank along with the supplies you’ll want to have on hand when doing so.

Why Do I Need To Clean My Heating Oil Tank?

The main reason for cleaning a heating oil tank is because sludge can form inside the tank. Sludge usually occurs when moisture enters the system one way or the other.

The most common reason for moisture in a heating oil tank is due to condensation. This occurs when the oil already in the tank is a different temperature than the oil that is used to fill it. Condensation occurs when these two oils meet and that’s where the moisture comes from.

How To Clean Your Heating Oil Tank

Cleaning your heating oil tank is generally best left to professionals, but you can do it yourself. It will take several hours to complete and you will want to have the following items before starting.

  • Container for oil
  • Towels or rags to clean up
  • Water hose
  • Air hose
  • Trisodium phosphate cleaner
  • Denatured alcohol

Now that you have the materials ready, you can start to clean the tank

1. Drain all oil from the tank

Find the drain valve on your tank and place the container under the valve.

Make sure your container is large enough to hold whatever oil is left in your tank.

Open the valve and let all the oil and sludge run out of the tank. Be patient as you want as much oil to come out as possible.

Next, grab a new container and place it under the drain valve. Now spray water into the tank from your hose to help loosen and remove any residual oil sticking to the inside of the tank.

2. Clean the tanks with TSP

After you have drained and hosed down the tank, close the drain valve. Now fill the tank with water and trisodium phosphate. You want to use about 1 cup of cleaner for every 5 gallons of water put into the tank.

You should have an idea of the capacity of your specific tank, so use this when determining how much TSP to add.

Now, use your air hose to stir up the mixture inside the tank, you want this to go on for a while as the mixture needs to fully dissolve.

Let the mixture sit inside the tank for at least 10 hours. Because of this, you should clean the tank when you know you won’t need it for at least a full day.

3. Drain the cleaner and dry the tank

Now you will want to drain all the mixture of TSP and water out of the tank. Do this the same way you drained the oil out earlier.

When the solution is fully drained, rinse the inside of the tank with the hose to remove any excess cleaning mixture still trapped inside.

Make sure to get all the solution cleaned out.

Allow the tank to air-dry as much as possible on its own. When dry, use 3 to 5 gallons of denatured alcohol to remove the rest of the water.

Pour the alcohol into the tank, making sure to hit all the areas of the inside of the tank.

Take your time here because you don’t want any moisture left inside the tank.

When you’ve used all your alcohol and are sure the tank is fully dry, close the valves and refill the tank with fuel oil.

How Clean Heating Oil Tank

Cleaning Your Heating Oil Tank FAQ

How often should you clean your heating oil tank?

Generally every 3 to 5 years. If you know moisture entered your tank or a cap or valve was faulty and let moisture in, you may want to do it sooner.

Sludge allowed to build up in the tank can damage other parts of the heating system, which could cost you more in the long run.

What causes sludge in an oil tank?

When moisture gets in the tank it can create sludge. Moisture generally enters the heating oil tank when the temperature of the oil in the tank is different than the oil being pumped in.

The temperature difference causes condensation, and this introduces moisture into the tank.

How do you remove oil from a home oil tank?

First, wait until the oil tank is nearly empty by using the fuel left in the tank. Then, locate the drain valve and place a container large enough to hold what oil is left under the valve.

Open the valve and let the oil drain out. Close the valve before refilling with oil.

Can you clean oil sludge?

Yes, a mixture of water and trisodium phosphate can clean oil sludge from most tanks. Very old tanks with years and years of sludge build-up may not clean up as well as newer tanks that were properly maintained.

Make sure to clean your tank at least every 5 years to keep the sludge build up to normal levels.

Final Thoughts On Cleaning Your Heating Oil Tank

Cleaning a heating oil tank can be a tough job that is often best left to professionals. But if you have a DIY spirit, you can tackle this task yourself.

Make sure to allow yourself at least a full day when attempting to clean your heating oil tank for the first time, as it takes quite a bit of effort to complete.

But if you follow the steps in this guide, you should have no problems.

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