Pump Controller Problems Explained – Troubleshooting Guide for Water-Fed Pole Systems

Modern water-fed pole systems rely on pump controllers to deliver steady flow, protect your pump, and keep your day running smoothly. When a controller starts behaving unpredictably—reduced pressure, pulsing, flashing error codes or cutting out—it can stop a job in its tracks. The good news is that these issues usually come from simple causes such as calibration, voltage drop, blocked hoses, or pressure-switch faults. This guide explains the most common problems professional window cleaners face and shows you how to resolve them quickly.

Q: "My pump is coming on and going off every few seconds"

Q: "My controller won't work properly, the pressure at the pole is not enough"

Q: "My pump won't run when I plug the pole in"

Q: "My pump won't run when I plug the hose reel in"

Pump controllers play a key role in keeping your water-fed pole system running smoothly. When a controller behaves unpredictably—low pressure, pulsing, or failing to run—it's almost always caused by calibration, flow restriction, or a simple power issue. New controllers ship with default settings that rarely match real-world van setups, so proper calibration is essential.

• Every new controller needs accurate calibration before you can expect stable performance. Manufacturers ship them with generic values, but each system has a different hose length, pump model, pole height, and jet size. You must set your controller to match your exact working environment.
• In most cases, the controller works once you increase the “CAL” value and set the Dead End Detection correctly. Follow the manufacturer’s calibration instructions exactly.
• If the pump cuts in and out every few seconds, the controller usually thinks it has reached a “dead end” and is shutting down to protect the pump. Calibration will normally fix this.

Q: "My Variflo V16 Digital Controller is flashing 'DE'"

• “DE” means the Dead End Detection has activated. The controller senses that water has stopped flowing, so it cuts power to protect the pump. This often happens when the CAL setting is too low or when the system has a restriction.
• Check for closed or partially closed valves, a twisted or kinked hose, a blocked strainer, a faulty tap, or dirt in the hose line.
• If everything is clear, increase the controller’s CAL setting as described in the manual. Many issues come from not raising CAL enough when the weather gets colder.

Q: "My controller works in the morning but not in the afternoon"

Q: "My controller has been working fine for months and now is playing up"

• The most common cause is low battery voltage. As the day progresses, the battery drops and the controller reduces power to protect the system.
• Re-check your calibration. Slight variations in temperature, water flow, and hose pressure can cause a controller that worked in summer to struggle in winter.
• Cold water thickens and flows less easily. Even with the same pump, colder weather increases resistance through hoses and jets. Increasing the controller’s CAL setting usually solves this.

Q: "There's nothing on the screen of my controller"

• This almost always points to a power supply problem. Inspect the battery, wiring, fuse holders, inline fuses, crimps, and any isolation switches between the controller and the battery.
• Vibration from driving can loosen terminals or damage poor connections, so check the wiring carefully.

Q: "My Variflo V16 Digital controller has the 'BAT' symbol on the screen"

Q: "My Variflo Analogue controller has the red light flashing"

Q: "My Varistream has just cut out and refuses to come back on"

• A “BAT” warning tells you that the controller is not receiving enough voltage to run safely. Low voltage is the second most common cause of pump controller problems after poor calibration.
• Low voltage can come from several sources:
  1. The battery genuinely needs charging.
  2. A poor-quality charger that never fully restores the battery.
  3. A split-charge relay that does not send enough charge from the vehicle’s alternator.
  4. Undersized wiring that cannot carry enough current to the pump.
  5. Runs of cable that are too long.
  6. Dirty, loose, or corroded cable connections that create voltage drop.
• If the controller shuts down during the day, this almost always means the battery voltage has fallen too low. Charge the battery fully before the next working day.

Q: "My Variflo V16 Digital controller has the 'PS' sign on the screen"

Q: "My Variflo Analogue controller has an orange flashing light"

• “PS” indicates a break or fault in the electrical path between the controller and the pump. The controller is detecting a problem with the pump’s internal pressure switch.
• A pressure switch can burn out, stick shut, or become stuck due to trapped water pressure.
• Inspect every connection from controller to pump: terminals, butt connectors, inline fuses, switches, and any plug-and-socket joints.
• In many cases, the quickest fix is simply replacing the pump’s pressure switch.

Conclusion

Pump controller issues can look complicated, but most problems come down to calibration, restrictions, voltage drop, or pressure switch faults. Once you understand what each warning means and how the controller protects the pump, diagnosing faults becomes much easier. With good wiring, a healthy battery, and a properly calibrated controller, your water-fed pole system will run reliably throughout the year—even in cold weather. Keep your setup clean, check fittings regularly, and don’t ignore early signs of pulsing or low pressure. A few minutes of maintenance prevents most mid-day breakdowns.