Monitoring the return filter (components 3.1 in the hydraulic scheme) is a preventive maintenance function. It reduces unwanted unit downtime by identifying and reporting a blockage in the return filter early on. This function increases the reliability and efficiency of the unit and helps the operator plan maintenance work. A clogged return line filter reduces the flow rate and leads to an unnecessarily high energy requirement.

function

The return line filter monitor function is available in 2 different variants. In the standard version (without additional ZF equipment), the maintenance interval is calculated purely based on operating hours. With the additional ZF equipment, on the other hand, the maintenance interval is calculated based on effective measurement data (pressure drop across the return line filter). To calculate the pressure drop, the additional ZF equipment includes an additional BP 3 pressure sensor in front of the return line filter. The pressure drop above the return line filter is measured with the 2 pressure sensors (BP 3 and BP 1). The higher the measured pressure drop across the return line filter (3.1), the greater the contamination and the longer the indicated maintenance interval.

On the basic screen, the percentage of progress up to the upcoming maintenance is shown under the register symbol (). When the maintenance interval reaches 95%, the required maintenance is signaled by the warning symbol () in the register on the basic screen and a maintenance message appears asking you to check and, if necessary, clean the filter screen in the return line (3.1).

Prerequisite

For both variants, a minimal software version is required so that the function can be used:

  • Standard (without additional ZF equipment), software SW61-1_2238A or newer → Unit software
  • With additional ZF equipment, SW61-1_2311 software or newer → Unit software

Reset maintenance interval

  • With additional ZF equipment, it is not absolutely necessary to reset the maintenance interval manually. After maintenance work has been carried out (filter screen cleaned), the maintenance interval is automatically reset if the [Reset maintenance filter Limit Value] has been exceeded. In case of problems, the maintenance interval can also be reset manual. Procedure → Reset maintenance Interval
  • In the standard version (without additional ZF equipment), the maintenance interval must be reset manual. Procedure → Reset maintenance interval

Adjustment of the return line filter maintenance interval

In the standard version (without additional ZF equipment), the maintenance interval is calculated based on operating hours. If the return line filter act clogged before the default operating time or only very little or not at all dirty after the set operating time has elapsed, this can be adjusted to the respective circumstances using the parameter [Return filter factor Limit].

With additional ZF equipment, the maintenance interval is calculated on the basis of measurement data, so there is no provision for an adjustment to calculate the maintenance interval. Only the [Reset Maintenance Filter Limit Value] can be adjusted.

Limit value factor return filter

The parameter [Limit Value Factor Return Filter] defines the limit value that is used to calculate the maintenance return line filter. The higher the value is set, the longer it takes for a maintenance message to appear.

NOTE!

Setting this parameter only affects the standard built-in maintenance interval for the return line filter.

  1. Select [Service] > [Parameter] > [Maintenance] > [Return line filter] > [Limit Value Factor Return Filter]
  2. Set the parameter to the desired value.

Reset maintenance filter limit value (ZF additional equipment only)

The parameter [Reset Maintenance Filter Limit Value] defines the limit value for automatically resetting the maintenance return line filter.

  1. Select [Service] > [Parameter] > [Maintenance] > [Return line filter] > [Reset Maintenance Filter Limit value]
  2. Set the parameter to the desired value.