Water-powered dilutors: unit maintenance

Remembering a few key points about how your water-powered dilutor works will help troubleshoot any problems and minimise the likelihood of damage or misfunction. Use this short check-list to guide you.   

This information was last updated in 2018.

Simple unit maintenance

While calibrating your dilutor, it is useful to bear in mind some important points about unit maintenance:

• Where appropriate check the basket filter in the unit head (See figure 1) to make sure it is clean. It can become clogged with debris in the water source, or concentrate fertiliser crystals can develop on it during periods of low or no use.

Figure 1. Basket filter removed from the unit head of the proportional dilutor ready for cleaning

• Ideally when a dilutor is not being used it should be washed out with plain water through the concentrate feed intake tube to remove any residual fertiliser solution
• Many dilutors have small O-ring washers on the valve seats which close the flow when injecting the concentrate. They can be ‘blown off’ the valves if initial water pressure exceeds unit tolerance levels.
• O-rings should be checked as part of each calibration to make sure they are in place and not damaged.
• To prevent O-ring displacement, the flow rate of irrigation water should be increased gradually to working pressure when the system is started up.
• When in use, the dilutor (if of the piston type) should make a steady and audible ‘click, click click’, as the piston is driven up and down within the unit.

Acknowledgements

The guidance is based on the content of Bulrush Horticulture Grower Notes GN10. Thanks also go to Russell Woodcock and Gary Woodruffe, Bordon Hill Nurseries, for their time and input into the production of this information and the video dealing with the calibration of water-powered proportional dilutors.