One zone giving variable flow readings

Hi - I installed my flow sensor today. I have 7 zones and six of the zones calibrated fine. But one zone continuously gives very variable readings - fluctuating from 8 gpm to 20gpm within 10-15 second intervals during the calibration. Other zones get to a constant amount and stay there. The zone that is fluctuating is running fine - sprinklers are watering with what appears to be a constant flow and good coverage.

Two questions:

  1. What could be causing the sensor reading variability on that one zone? Support told me I should hire an irrigation professional to open the valve because some dirt or calcium build up could be in there and causing weird vibrations. Is that really possible? Seems odd given the zone is watering correctly…if it is possible, do I really need a professional to do this? I went to my valve box (house was built one year ago so everything is close to brand new) and I found the valve; six screws and it seems the top of the valve comes off but I’m not sure what I’d be looking for in there.

  2. For now I just picked a value for that zone that’s high (e.g. 20gpm) and am hoping it’ll water correctly. Else I’ll turn that zone’s flow sensing off. Open to any other suggestions.

I have this same problem and posted this recently too. No replies to my question either. I’m guessing the flow meter is just inaccurate.

I would suggest reading this thread:

It is possible you are going above the 25gpm limit on the one zone. The other possibility is that your installation is marginal. The asymmetric flow created by a marginal install would get worse with higher flow rates. So, it could work well on low flow zones and then have a problem with a high flow zone.

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