Properly cleaned and maintained sprayers will make mid-season application smooth.

Weed escapes haven't made their presence known yet, but soon enough, there will be reason to dust off the spot sprayer and clean up trouble spots. That's not to mention the mid-summer spray around the farmstead to keep fence rows, bins and buildings looking good and less inviting for rodents. If your sprayer won't wake up after its winter slumber, here are a few troubleshooting tips to get back into business.

The motor runs but will not prime

1. Check all screens first. There are three in the system.
2. Pull the suction hose from the bottom of the tank, remove the suction screen, and with a garden hose run water into the pump. This will flush any small objects which may be under the check valve or diaphragm.
3. Still won't prime or pump? Locate a set screw, with hex head, in the center of the pump head and screw it in several times. This may free up the check valve. If it is still stuck, remove the screw and spray inside the pump with WD-40. Re-install the screw and let the pump soak for a while and retry.
4. If the pump still won't prime, disassemble the pump, checking the check valve springs and seals as well as the diaphragm seal. Look for two springs stuck together, or seals cracked or deformed. Replace parts as needed.

How to check the switch if the 12-volt motor will not run.
Remove the red wire connected to the switch assembly (wire goes into the motor) and connect it to the terminal prior to entering the switch. If bypassing the switch causes the motor to run, the switch assembly is bad. If the motor does not run and there are 12 volts present, the problem is within the motor. It will need to be returned to a factory representative.

The motor cycles on and off very rapidly.

1. The pressure switch senses the outlet pressure of the pump. It will turn the electrical power off to the pump at a predetermined high pressure point. As the outlet side of the pump is opened, the pressure starts to drop to a predetermined setting (typically 15 to 20 psi), at which point the contacts in the switch will close, causing the pump to start automatically. The pump will then "pump up" until it reaches shut-off pressure. If the flow demand is very low, the pump may reach the high pressure point and cause "cycling" (the pump turns on and off rapidly). This is not a problem unless the pump is subject to continuous cycling within 1-second intervals for long periods of time. The pressure switch comes pre-adjusted from the factory, but can be fine-tuned for specific applications. However, excessive adjustment could cause damage to the pump. Depending upon the design, the motor could be subject to severe overloads.
2. The pressure switch is adjustable within a pressure range (follow pressure range on pump). Adjustment can be done by turning the 5/64-inch hex-head set screw in the center of the switch body. By turning the set screw counter clockwise you are decreasing both the shut-off point and turn-on point of the pump. For example: If you have a 40 psi shut-off and a 20 psi turn-on, by adjusting the set screw clockwise, shut-off can be adjusted to 45 psi and turn-on will be 25 psi. Usually the differential will not change. Always install a pressure gauge (for reference) in the outlet side of the pump when adjusting the shut-off point of the pressure switch.

CAUTION! Do not turn the set screw more than two turns maximum in clockwise direction. We do not recommend that output pressure be adjusted higher than the maximum pressure rating as so noted on the pump label.