New Biweekly Series: The 12 Most Common PD Pump Issues in Fertigation & Chemigation
Solving the Top 12 PD Pump Problems in Fertigation – Part 1 of 4
This is Part 1 of a new biweekly technical series by I-Feeder Global Dosing Systems, aimed at solving the 12 most common PD pump issues we see in fertigation and chemigation systems.
Every second week over the next two months, we’ll cover 3 problems at a time, with practical diagnostics and solutions straight from the field. Whether you’re an irrigation engineer, agronomist, or operations manager, this is for you.
Let’s begin with three common—and costly—problems:
🔹 Issue 1: Pump Losing Prime
Symptoms:
No flow despite motor running
Bubbles in outlet line
Erratic dosing
Long re-priming after shutdowns
Root Causes:
Suction air leaks (often invisible)
Pump mounted above fluid level
Cavitation from vapor-lock or viscous media
Incomplete wet-priming
Solutions:
✅ Position pump 30 cm above tank outlet
✅ Use chemical-rated, non-collapsing suction tubing
✅ Add foot valve + strainer to avoid backflow
✅ Test regularly for micro-leaks with vacuum hold tests
✅ Use air release valve or priming assist chamber in complex setups
🔹 Issue 2: Crystallization in Lines
Symptoms:
Injection point blockages
Stiff or cracked tubing
Pressure spikes or low-flow alarms
Fluctuating EC in fertigation zones
Root Causes:
Acid or high-salt fertilizers drying in place
No flushing or automatic purge
Incompatible mixing (e.g., phosphate + calcium)
High summer temps in stagnant pipes
Solutions:
✅ Flush lines with clean water post-dosing
✅ Automate flush cycles with 3-way solenoids or timers
✅ Use non-reactive injection quills (PVDF or SS316)
✅ Avoid in-line mixing of incompatible products
✅ Design short dosing circuits to reduce stagnation time
🔹 Issue 3: Inaccurate Calibration
Symptoms:
Over- or under-dosing nutrients
Discrepancies between controller flow and real output
Yield issues tied to nutrient misapplication
Root Causes:
Calibrating with water instead of actual fluid
Not accounting for pressure variations
No inline flow feedback
Seasonal viscosity changes affecting output
Solutions:
✅ Always calibrate with the actual formulation
✅ Recheck calibration monthly or when switching products
✅ Install calibration cylinder + flow verification meter
✅ Include viscosity adjustments into the dosing curve
✅ Set alarms on major variance between controller and inline meter
📆 Coming in 2 Weeks – Part 2:
4. Viscosity-induced flow reduction
5. Pressure relief valve design faults
6. Cavitation & suction-side restrictions
📩 Subscribe or send your questions: technical@ifeederglobal.com
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