Always check the pressure rating of non-drip check valves before purchase or installation.

One of the causes of nozzle bodies that are slow to shut off, or that continue to drip after the boom section has been turned off, could be the pressure rating of the non- drip check valve. Some non-drip check valves are rated to open at pressures as low as 0.75 bar. 

It is very useful to have the highest pressure rated non-drip check valve that will match the nozzle types being used and the minimum setting on the rate controller (e.g. a 2.0 bar rating for use with low-pressure air-induction nozzles). 

An alternative to the check valve is to use either an electric nozzle shut-off or an air nozzle shut-off system. Both electric and air shut-off systems provide positive shut-offand turn-on of nozzles.