Troubleshooting - Overflow Filler Nozzles and Inconsistent Fills

Overflow filling machines are used to create an aesthetic quality where bottles are filled to the same level regardless of minor differences in the interior volume of the containers. There is likely nothing more frustrating to the user of an overflow filler than seeing uneven fills coming from the machine. While not a common occurrence, there are several factors that can lead no non-level fills. Luckily, a quick solution almost always exists for such an issue. Checking the overflow nozzles themselves is always a good place to start.


To reach a specific level in a bottle, nozzle spacers are used to allow the fill head to dive to a specific depth in the container. When bottles or products are changed over, the spacers will often need to be adjusted for the fill level. When uneven fills occur, the operator of the machine should always check to ensure each nozzle is using the same set of spacers. This is especially true if one fill head is consistently over- or under-filling. A quick addition or removal of a section of the spacer can correct the issue.

Height Adjustment

Similarly, when changeover includes a different bottle size, the starting height of the nozzles will need to be adjusted. This simple process involves lining up bottles and manually diving the fill heads until the nozzle springs are properly compressed, to a point where a fingernail or dime will fit between the coils. When unlevel fills occur, a packager can also check the height and easily adjust it with the turn of knob.

Nozzle Seals

Overflow fillers achieve level fills by creating a seal over the bottle opening during a fill and allowing product to return to a holding tank via an overflow port. The nozzle seals are a contact part and can require replacement over time. While packagers should not be replacing seals on a regular basis, these seals should be checked when the fills produced are not level across all fill heads. If wear can be seen on the seals, or if leaking seems to be occurring at bottle openings, the time has probably come to replace the seals.

Tubing Connections

Overflow fillers may run up to sixteen fill heads on a single machine. Each of these fill heads will include a product pathway with tubing and connections. In the event of non-consistent fills, packagers should also check these connections, including not only those running to the fill heads, but any other connections from the tanks, fill bar or other locations. Tightening a loose fitting may be all that is necessary to return to reliable level fills.

Pump Speed

While the overflow nozzles include several components that may be the cause of inconsistent fill levels, sometimes the issue stems from something other than the nozzle. Liquid Packaging Solutions overflow fillers allow the operator to ramp pump speeds up and down throughout the fill. The settings for the pump speed will normally be found on the operator interface on the control panel. Running a pump at full speed for the entire fill, for example, can lead to a pressure build up that can compromise the seal created by the machine, leading to a leak and inconsistent fills. If the nozzles, seals, spacers and connections all appear a go, a packager should check the pump speeds and adjust accordingly to bring the fills back to level.

While the above fixes will solve a majority of issues for uneven fills on an overflow filling machine, they are not an exhaustive list of possible causes. For anyone having issues with a fill-to-level system, LPS representatives are always available to assist in troubleshooting and solving inconsistent fills. LPS Packaging Specialists can be reached Monday through Friday from 8am to 4pm Central Time at 1-219-393-3600.