How to perform Soil tensiometer maintenance or service?
- Tensiometers are weather proof and generally require very lift the service.
- Servicing is the best performed soon after irrigation (soil is wet) to avoid drawing additional air in the tensiometer.
- Add water (distilled) before pumping vacuum pump or syringe.
- When using a syringe, seat the tip of the syringe into the small opening at the bottom of the reservoir (against O ring). Apply some pressure to the seal the tip and pull on the syringe handle to get a gauge reading in the upper half of the range, typically 70-80 Cbar. Then slowly release and replace cap and tighten only by ¼ turn past the first contact.
- Check out for abnormal amount of air.
- Watch out for tensiometer that accumulate abnormal amounts of air. Their ceramic tips draw in much air at low tension. These tips are usually detective and may need replacement.
- Some tensiometer may require gauge augments. The pointed may need to be zeroed, this is needed to take care of difference in pressure due to elevation change.
- The ceramic tips can mineralize over time and slow down the response. To test such the tensiometer is hang vertically fill with water to the top of the reservoir and allow to drain over 24 hours, when the cap is removed if less than 25mm of water drains the tip should be replaced.
- The stopper/cap can become hard over years of service or damage by frequent over tightening and require replacement. The stopper can be replaced individually.
