top of page
Search

Pump vs Motor: What’s Really Failing?

  • Writer: Lincoln Jones
    Lincoln Jones
  • 4 days ago
  • 2 min read

A 5-Minute Troubleshooting Guide That Saves You Hours (and Thousands)


ree

You hear the familiar hum… then silence. The chemical feed pump that was running perfectly yesterday is now dead. Your first instinct: “The motor burned out.” 90 % of the time, operators guess wrong — and order the expensive part that wasn’t actually the problem.


Here’s the dead-simple flowchart we use in the field every day to diagnose pump vs motor failure in under 10 minutes.


Step 1 – Is There Power AT the Motor?

  • Check voltage at the motor terminals (not just at the panel).

  • No voltage → wiring, VFD, overload, or control relay issue.

  • Correct voltage → keep reading.


Step 2 – Can You Spin the Shaft by Hand?

  • Disconnect power and remove the pump head (or fan cover on larger motors).

  • Try to rotate the shaft with your fingers or a wrench.


Spins freely → The motor is almost certainly fine. The problem is inside the pump (seals, impeller, check valves, clogged foot valve, etc.). Locked or very stiff → Motor bearings or windings have failed.


Step 3 – Listen for the Tell-Tale Hum

  • Reconnect power for 2–3 seconds only.

  • Humming but no rotation → single-phasing, seized rotor, or bad capacitor (centrifugal pumps).

  • Dead silence → open winding or completely failed capacitor.


Step 4 – Quick Megger Check (if you have one)

  • <1 MΩ to ground → motor is toast.

  • 20 MΩ → motor windings are good → look at the pump.


The Most-Common False Culprits

  • Blown capacitor (sounds like a dead motor but costs $40–$80)

  • Seized or crystallized check valves in the pump head

  • Clogged foot valve or injection quill

  • Air-locked diaphragm pumps


Bottom Line

Before you spend $1,500–$8,000 on a new motor, spend 10 minutes with this checklist. Nine times out of ten the pump is the real problem — and it’s usually the cheaper, faster fix.


Need someone to diagnose it properly the first time? Call or text our service team at (403) 437-7888.


Because the right answer shouldn’t cost you a motor you didn’t need.


Academy Water (403) 437-7888 | academywater.ca

Comments

bottom of page