What does each measurement mean?
A sensor that hangs from a flange needs six numbers. Two of them, the clearance and the sensor length, come from your supplier. The rest you measure on the tank.
| Input | Example | What it is |
|---|---|---|
| Inside depth, H | 870mm | Inside bottom to the inside of the top wall. |
| Top wall, t | 3mm | Tank top thickness at the mounting point. |
| Gasket and flange gap, g | 4mm | Length reference to the outside of the tank top. |
| Head height, h | 0mm | Datasheet length above the flange face. |
| Clearance, c | 15mmtypical | Tip to inside bottom. Supplier rule. |
| Sensor length, L | 1000mmtypical | Datasheet length before any cut. |
Typical value. Replace with your tank measurement or your sensor datasheet value.
How do you cut a fuel level sensor safely?
Find the length reference
The datasheet or the label says where the sensor length starts: the flange face or the top of the head. Everything below depends on it.
Measure the depth
Lower a straight rod through the mounting hole until it touches the bottom. Mark it level with the outside top of the tank, pull it out and measure to the tip. This figure already includes the wall, so enter it as the depth and set the wall to 0.
Measure the gasket gap and the head
Measure how far the length reference sits above the tank top once the gasket is compressed. Enter the head height only if the length is measured from the top of the head.
Enter the values and read the cut
The tool shows the cut, the number of extension pieces and the probe length after the cut. Read the supplier limits on the second tab.
Mark and dry-fit
Mark the cut with tape on the probe. Offer the probe to the tank without sealing it, and check that the tip clears the bottom.
Cut and deburr
Cut at the mark using the method your supplier gives. Cut the free end unless the supplier says otherwise. Remove burrs before the sensor goes in.
Recalibrate
The probe length changed, so the old table no longer matches. Build a new one with the calibration table generator.
How is the cut worked out?
The required length R is measured from the length reference of the sensor down to the probe tip. The set length is the sensor plus the extension pieces. The tool uses the smallest number of pieces n that makes the set at least R long.
Worked example
- Default values: depth 870 mm, wall 3 mm, gasket gap 4 mm, head 0 mm, clearance 15 mm, sensor 1,000 mm.
- Required length: 0 + 4 + 3 + 870 − 15 = 862 mm.
- The sensor alone is long enough, so no extension piece is used. Cut: 1,000 − 862 = 138 mm.
- A deeper tank of 1,900 mm with no wall, gasket or clearance and a 1,000 mm extension piece: the set is 2,000 mm, so cut 100 mm.
Common mistakes
- Counting the wall twice. A rod measured from the outside top already includes the wall.
- Using the wrong length reference. A length measured from the top of the head is longer than one measured from the flange face.
- Forgetting the joint loss. Each joint can shorten the set. Take the figure from the datasheet.
- Skipping the recalibration. After a cut or an extension the old table reads wrong levels.
Assumptions and limits
The tool does plain arithmetic on the values you enter. The defaults are examples and typical installation values, not the specification of a Tracom sensor. Cutting rules, minimum lengths and clearances belong to the sensor supplier. For the next step, build the table with the Fuel Tank Calibration Table Generator and follow the calibration field sheet.