Heating oil tanks have remained virtually unchanged for decades. And unfortunately, so have the gauges inside them! The most basic type of oil tank gauge, which most heating oil tanks have, is called a float gauge. Float gauges notoriously go bad over time, and in this post, we will talk about the accuracy of a heating oil tank gauge.
How A Float Gauge Works:
A float gauge is a remarkably simple mechanism that is mounted in the top of a heating oil tank. It features a plastic sight at the top, with a disc inside to indicate the level. This disc is attached to an articulating arm with a hinge in the middle. At the other end of the arm is the float itself. While the floats were originally made of cork, they are now usually a plastic material that lasts longer. As the level of oil lowers, the float lowers with it, and the disc is lowered accordingly.
The float only provides an approximate oil level.
How Do I Read A Float Gauge?
The disc in the plastic sight on a float gauge indicates an approximate level. The key word here is approximate! A float gauge is not a precision instrument. When reading a float gauge, you will need to know what size oil tank you have. Most oil tanks are 275 or 330 gallons and look like the one pictured below.
Tip: A 275 gallon home heating oil tank measures five feet long while a 330 gallon heating oil tank measures 6 feet long.
Once you know your tank size, you will have to determine what your float gauge is reading. The levels are primarily fractions of a tank: 1/4, 1/2, 3/4, or Full. Refer to our heating oil tank chart <INSERT LINK> to determine how many gallons are in the tank.
To be safe, always re-order your home’s heating oil at a quarter of a tank when using a float gauge!
When Reading Your Own Tank:
The disk shown to the left indicates roughly how much home heating oil is in the oil tank. Once you know the approximate level, check our Oil Tank Chart <INSERT LINK> to determine the number of gallons.
How Accurate Is My Float Gauge?
Unfortunately, a float type gauge is not a perfectly accurate device. There are two main reasons for this:
Float gauges go bad over time!
After many years sitting in heating oil, the float can actually build upsludge over time. This float below was removed after it was no longerworking properly. Furthermore, the float gauge can occasionally endup getting stuck. If the gauge rotates at all in its fitting, the float armwill get stuck against the side of the oil tank, causing the level not to change.
What To Look For
This is what the float on aheating oil float gauge looks like after years in an oil tank. For this reason, float gauges cannot be counted on to provide an accurate oil level.
Float gauges do not account for tank geometry!
Since float gauges simply work by having the arm go up and down,they do not take into account the curvature of the oil tank. In the middle of the fuel oil tank, the walls are straight up and down. Assuch, there is significantly more oil than in the bottom section of the oil tank where the walls curve in (see below). When an oil tank gauge reads 1/4 or below, the level will suddenly start lowering more quickly without warning.
Avoid this issue entirely when you sign up for our Automatic Delivery Service!
How Automatic Delivery Service Works:
Our internal software tracks your previous oil purchase history and factors in real-time variables like the weather/temperature to accurately predict when youwill be in need of 150 gallons. To put this into context, our system will rarelyhave us deliver (if at all) during the summer but due to colder weather in thewinter, will calculate much more frequent deliveries during that time.
Typically (even to our customers who burn the most oil), we automaticallydeliver about once every 3 to 5 weeks during the winter and maybe once if atall during the summer. The exact time in-between deliveries varies fromcustomer to customer due to the fact that no two households burn oil at exactlythe same rate. The automatic rate is based on the current market price of oilhowever, you will always receive the best price we can offer which is the 150gallon rate. Even if you take less than 150 gallons, as an Automatic customer,you are always guaranteed that price.
