In principle, it eliminates the possibility of overfilling a fuel oil tank. First, the tank truck driver must determine the free capacity – for example, they can do this using the SmartBox®. Based on this value, the mineral oil retailer knows how many litres of fuel oil fit into the tank. If they have miscalculated or the filling level indicator is not displaying correctly, the limit indicator still provides protection. But how do you ensure that the limit indicator will definitely respond when it comes to it?
The limit indicator test device type F-Stop® GWG-PG 1 provides safety. For example, this device allows a specialised company to carry out a test to determine whether the safety device functions correctly against overfilling. The function check of the limit indicator is prescribed as part of a one-off and recurring inspection of the fuel oil system according to AwSV. However, the fitting does not have to be disassembled and removed from the tank.
Special requirement for older limit indicators
Only in the case of existing fuel oil consumer installations with limit indicator in hole design, a visual check must be carried out at least once a year.
Section 46 AwSV stipulates that the operator must perform regular function checks on a safety device.Normally, it is the case that the tank truck driver carries out this check during filling.
Contracting a specialist company
However, if the operator of a fuel oil system has no qualified or competent personnel, they should contract a specialist company to carry out the function check on the limit indicator.The special focus is on checking the shut-down time of the limit indicator. This is clearly defined according to EN 13616 in order to rule out overfilling.
Various types and brands of limit indicator checking and test devices are available on the market.To check the functionality, we recommend the test device type F-Stop® GWG-PG 1. The simpler test devices are no longer sufficient to meet the requirement for shut-down time.
The check takes place as follows:
- The specialist fitter connects the coupling socket of the test device with the connector of the limit indicator. The coupling socket fits the common fittings, such as type GWD and type GWS.
- The tester then starts the heating process by pressing and holding the “TEST” button.
- If the PTC thermistor heats up properly, the LED display changes to enable.
With the “enable” display, the safety fitting fulfils its electrical default values during this simple test. A bit more time-consuming, but all the more important is checking the shut-down time in the so-called dry-wet test to check the function. For this, the limit indicator must be disassembled and immersed in the operating medium.
The time in which the limit indicator sends the shut-down signal to the overfill prevention must not exceed 1.5 seconds. On the display of the F-Stop® GWG-PG 1, the tester can read how many seconds the safety device needed for shut-down. If the shut-down time is over 1.5 seconds, the limit indicator must be replaced immediately.