Analysis of the Reasons for the Decrease in Flow Rate of the Power Sprayer

Analysis of the Reasons for the Decrease in Flow Rate of the Power Sprayer 

I. Inflow / Filter Screen Blockage (Most Common)

Filter screen and bottom valve of the suction port are clogged.

Residual drug liquid, water plants, mud, and debris are wrapped in the inlet filter screen, resulting in insufficient inflow and direct cause of reduced and intermittent outflow.

Treatment: Remove the filter screen and bottom valve, clean with clean water; if damaged or deformed, replace directly.

Inlet pipe bent, flattened, aged and cracked

The pipe is bent, leaking air, and the pump body sucks in air, forming an air blockage, resulting in weak outflow and sudden drop in flow rate.

Treatment: Straighten the pipeline, replace the damaged, hardening, or aged water pipes directly; tighten the interface clamps to prevent air intake.

II. Pump Body Failure (Core Components)

One-way valve in the pump gets stuck, accumulates dirt, or wears out.

Drug liquid impurities get stuck on the one-way valve plates, causing the valve to not close tightly or not open properly, resulting in severe backflow, and a decrease in pressure and flow rate.

Treatment: Remove the pump head, take out the valve plates and valve seats for cleaning; if the valve plates are deformed or the sealing surfaces are worn, replace the entire set of one-way valves.

Diaphragm / rubber cup ages, breaks, or hardens.

Most motorized sprayers are diaphragm pumps. The diaphragm cracks and loses elasticity, preventing the pump cavity from forming an effective negative pressure, resulting in the pump not being able to suck in water and having a weak outflow.

Symptom: Normal idle, but no pressure when connecting the water pipe.

Treatment: Replace the diaphragm assembly and sealing ring.

Air remaining in the pump cavity (air blockage)

First use or after changing water, no air was released, and the accumulated air in the pump could not be normally sucked in.

Treatment: Open the water outlet switch, let the machine run unloaded for a moment until the water outlet is continuous and without bubbles.

III. Pipe / Switch / Spray Head Blockage

Spray head, spray plate, filter screen blocked

Pesticide sediment, powder, and impurities block the spray holes, resulting in: the pump is powerful, but the outflow is fine, the range is short, and the flow rate is small.

Treatment: Remove the spray head and spray plate, rinse with clean water, clean the small holes with a soft brush, and never use iron wire to forcefully insert (it is easy to damage the large diameter holes and reduce atomization).

Handle switch, pressure regulating valve blocked / stuck

The valve core of the switch gets clogged with dirt, and the opening is insufficient; the pressure regulating valve fails and the pressure cannot rise, resulting in a decrease in flow rate.

Treatment: Disassemble and clean the valve core, pressure regulating spring, and valve seat, add a small amount of lubricating grease if the movement is not smooth.

Outflow main pipe, diverter blocked

After long-term use, the drug liquid accumulates and impurities accumulate on the inner wall of the pipe, reducing the diameter.

Treatment: Rinse the entire pipe, and if severely clogged, soak with a chemical agent to clear.

IV. Power End Speed Insufficient (Engine / Motor Issues)

(Manual model: Gasoline engine)

Air filter clogged, spark plugs with carbon deposits, poor fuel supply → The engine speed is low, the pump speed is insufficient, and the flow rate is reduced.

The throttle pull wire is not in place, or the air intake valve is not fully open, resulting in insufficient power output.

Treatment: Clean the air filter, spark plugs, and carburetor according to the maintenance method for lawn mowers, adjust the throttle to the maximum opening.

(Electric model)

Battery depleted, insufficient voltage, long power supply lines / thin wire diameter → The motor speed decreases.

Carbon brushes of the motor are worn, and the rotor is dusty, resulting in reduced power.

Treatment: Fully charge the battery, shorten the long lines; inspect and repair the motor carbon brushes and wiring.

V. Sealing and Return Water Issues

Sealing on the suction side is not tight, continuous air intake

The inlet joint and sealing ring are aged and leak water and air, causing the pump to "infiltrate air", resulting in unstable pressure and fluctuating flow rate.

Treatment: Replace the sealing ring and gasket, tighten all pipeline joints.

The pressure regulating valve is set too low

Manually set the pressure knob too low, the outflow flow rate naturally decreases.

Treatment: Gradually increase the pressure regulating valve, observe the water outlet state, and adjust to the normal pressure.

VI. Pesticide Liquid and Environmental Factors during Use

The pesticide concentration is too high, and the powder is not fully dissolved

Pesticide powder and viscous liquid are prone to sediment and block the filter screen, spray head, and valve group.

Treatment: Pre-dissolve the pesticide liquid, stir evenly before pouring into the pesticide box.

The liquid level in the pesticide box is too low

The water level is close to the suction port, easily sucking in air, resulting in a decrease in flow rate.

Treatment: Timely replenish the pesticide liquid to avoid dry suction.