Oil tank piping requirements sketch Guide to Oil Tank Gauges
Where is the oil tank gauge? How much oil is in the tank? Remote readout oil tank gauges

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Heating oil storage tank level gauges:

We discuss: How to find the oil tank gauge? How to find out how much oil is in the oil tank. Heating oil tank gauge installation, reading, testing, repair guide: how much oil is in the heating oil tank? How accurate is the oil tank gauge?

This article series escribes how to find, read, and test the oil gauge on a home heating oil tank.

We also discuss: What are the different types of oil tank gauges and indicators of oil level? Types of oil tank gauges to measure how much oil is in the oil tank;

Special gauges for buried oil tanks - underground tanks - tell how much oil is in the tank without having to use a dipstick; Heating oil tank gauge accuracy, inspection, installation, defects, repair guide.

If your oil fired heating boiler, warm air furnace, or water heater has stopped working, one of the first things to check is whether or not you've run out of fuel. If your oil tank is above ground indoors or outside it should have a fuel level gauge installed similar to the one shown in our photo.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

How to Find, Read, and Test an Oil Tank Fuel Level Gauge

Heating oil tank gauge (C) Daniel FriedmanOil tank gauges are pretty simple to find, recognize, and read. If your heating oil tank is above ground outdoors or indoors, look on top of the tank for a device similar to the one in the photos shown on this page.

If the heating oil tank has been enclosed for cosmetic or other reasons, it may be necessary to make an access door that can be opened to give a view of the oil tank gauge.

If the heating oil tank is inaccessible above ground or buried, remote oil level gauges are available. Installing a remote-reading oil tank gauge permits reading of the oil tank level from an readout device inside the building.

[Click to enlarge any image]

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How does an oil tank gauge work?

Oil tank float gauge Evidence of leakage around the oil tank gauge (C) Daniel Friedman

Shown at above left is a typical hinged-type oil storage tank float gauge.

Other oil tank gauges may use a rigid vertical rod and moving float or an electronic oil level sensor method.

A float assembly inside the oil tank moves up and down along with the level of oil inside of the oil tank. As the float assembly moves up or down it pushes a metal rod upwards (oil level in the tank is going up) or lets the metal rod fall down (oil level in the tank is dropping).

On top of the metal rod is an indicator, such as the red plastic disk in our photo below. The red plastic disk forms a line inside the oil tank gauge, showing the level of oil in the tank.

Heating oil tank gauge (C) Daniel Friedman Heating oil storage tank level gauge in cm - New Zealand (C) Daniel Friedman

In the photo of an oil tank gauge at above left the red disk is sitting above 3/4 - showing that the heating oil level in this oil tank is more than 3/4 full.

The gauge is only close to accurate when the oil tank (round or oval in shape) is empty, half-full, and completely full levels.

Oil tank gauges are more accurate on rectangular-shaped oil tanks and still more accurate oil tank measurement systems are available.


At above right the oil tank gauge installed on this Stewart Island, New Zealand oil storage tank reads oil tank level in cm - which works nicely to give an idera of how much oil remains if the tank's height is close to the gauge's operating range. The tank where this particular gauge is installed is shown below.

Oil storage tank on Stewart Island, New Zealand (C) Daniel Friedman

How do we know that the oil tank gauge is working?

Old oil tank gauge (C) Daniel Friedman

Well it's easier than you might think.

On most oil tank gauges, the plastic tube that covers the actual moving gauge parts is just screwed into the cast iron base that holds the gauge assembly. Once in a while when we've wondered if our oil tank was really empty, or when an owner has reported that the oil gauge seems to "stick" we've done this simple test.

Unscrew the plastic cover by hand. Don't grab it with Vise Grips™ or you'll probably break the plastic. The gauge cover turns counter-clockwise to remove it.

If you did break the oil tank gauge cover it's not a catastrophe - the heating system will still work, but you should replace it before your next oil delivery because a broken or missing oil tank gauge cover could lead to a costly oil spill during an oil delivery.

Now that the cover over the oil tank gauge has been removed and set aside (where it won't roll under the oil tank and get lost), and presuming your tank gauge is not already sitting at the bottom of its range of travel (empty), just press the top of the gauge indicator rod downwards slowly and gently.

You will feel a little resistance because you're pushing a rod and float down into the heating oil inside tank. When you have pushed the indicator partly or all the way down, release it.

You should see the tank gauge rise back to about where it was before. This tells you that the hinged mechanism and float are still in place and that they are moving without obstruction.

If the gauge is broken, lost, or damaged, the entire assembly can be replaced by your heating oil technician. Remember that a heating oil tank gauge is not lab-grade equipment. It is not precise to the quart, probably not even to the gallon.

We have made a video of the procedure for testing an oil tank gauge and will post it here soon.

What else goes wrong with heating oil tank gauges?

Seeping oil leak at the filler pipe (C) Daniel Friedman

Plastic bottle stuck into top of heating oil tank used outdoors © D Friedman at

Typically the oil tank gauge vial is a screw-in part obtainable from your oil heat service dealer or from online oil tank gauge parts suppliers. - thanks to reader GC for this comment.

Missing oil filler caps (C) Daniel Friedman

Here is a gauge on an outdoor oil tank. The red button resting at the bottom of the plastic tube to left of the galvanized tank vent pipe shows that this oil tank is probably empty.

This is a poorly installed oil tank, exposed to roof runoff, freezing temperatures, improperly closed vent opening, and more.

Watch out: Check to assure that the oil tank gauge is present, and that its protective cover is tight. Loose or broken oil tank gauges can cause spills during tank fill operations.

How to Find Out How Much Oil is in a Buried Oil Tank or an Above Ground Oil Storage Tank that is Missing its Gauge?

Probing a buried oil tank (C) Daniel Friedman

Your oil company can provide a stick, a folding rule, or even a string and weight that can be placed into an oil tank to locate the bottom of the tank and to determine the level of oil in the tank.

The depth of the oil in the tank is measured by marking the top of the tank on the stick or oil tank gauge, then placing the stick into the oil tank and withdrawing it.

The oil level seen on the stick is compared with the distance from bottom of the stick (bottom of the oil tank) to top of the oil tank (which we marked on the stick).

In the old days people kept an oil tank stick that was already marked and calibrated to tell them how much oil was in their tank.

Today if we use a folding measuring rule or a generic "stick" to "stick the oil tank" to check oil level, we need to know the volume and shape of the tank as well as the depth of oil on the stick in order to calculate the number of gallons in the oil tank accurately.

In the photo our client is discovering a surprise buried oil tank at a farm we were inspecting.

Remote Readout Oil Storage Tank Fuel Level Gauges

Antique gauge for buried oil tanks (C) Daniel Friedman

Some buried oil tank systems use an oil tank gauge that measures oil in the tank and gives a reading at a remote location such as indoors near the heating boiler - which is pretty convenient in nasty weather.

Our photo above shows an antique gauge used with a buried oil tank. Modern remote oil tank gauges include sensors which provide an LED, an analog or digital dial, or another form of electronic indication of the level of oil in the buried or remote oil tank. Remote oil tank readout gauges can communicate by wire, by wi-fi, and over the internet.

But roughly, the oil tank stick procedure can tell us if the tank is half full, 3/4 full, or nearly empty.

Remote Readout Oil Tank Fuel Level Gauges

iLevel remote sensor retrofit oil storage tank gauge at, distributed by FuelMinder and othersSeveral companies make sensors and remote-readouot gauges that permit reporting of the fuel level in an inaccessible or buried oil storage tank.

Technologies include (antique) fuel level gauges like the one we show above, operated by an actual oil level liquid tube, hard-wired fuel levek sensors and oil tank gauges, and oil tank level sensors that combine with a wireless technology to report oil tank level.

Illustration: the iLevel remote readout oil storage tank fuel level gauge that retrofits to an existing oil storage tank gauge.

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Most of the remote reading oil tank gauges described below as well as other oil tank sensor products are available from Syba Systems, the first contact link given below. Some of these remote reading oil tank gauges are also sold on Amazon as well as at your local heating equipment parts supplier.

Other product brands besides those in our list include Sentry Tank Monitors, Afriso Unitel pneumatic oil tank gauges, Levelometer, Jarhead Tank Gauges, Petro-Meter oil tank gauges for industrial applications, and others.

Beckett remote readout oil storage tank level gauge at

Smart remote readout oil tank gauge at

How accurate are oil tank gauges & how to read the oil tank gauge accurately

Oil tank parts schematic showing the gauge (C) Carson Dunlop Associates

This topic has moved to OIL TANK GAUGE ACCURACY


Continue reading at OIL TANK GAUGE ACCURACY or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

Or see OIL TANK GAUGE FAQs - questions & answers about oil tank gauges posted originally at this page.


Or see HEATING OIL USAGE RATE to compare oil tank gauge readings with oil consumption rates.

Or see this

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