Diaphragm pumps are great pumps for weed control spray rigs, deep root feeding rigs and landscape sprayers. The pumps can handle a wide variety of materials while supplying good volume and pressure. These pumps require oil for lubrication. Most have an external oil reservoir that is visible to the spray tech. The first lesson is that techs MUST check the oil reservoir BEFORE starting the pump. If there is no oil, or there is a white milky liquid, do not start the pump. The photo shows what happens if you do.
The second lesson is that sometimes the diaphragms fail while the applicator is working. The pump will continue pumping. There may be a change in pressure or the sound that the pump is making. Train technicians to be aware of these things and to return to the vehicle and check the pump if they think there may be a problem.
The third lesson is don't wait for diaphragms to fail. Perform preventative maintenance regularly. Replace diaphragms (and other key parts) BEFORE they fail.
Finally, the pressure control valve on this pump was stuck in the highest possible position. The technician was spraying weeds at 360 psi! Technicians must be advised that if they have a problem, they are to report it promptly. This expensive issue could have been avoided had the technician been better trained.
