How To Test A Pool Motor Capacitor

6 min read Jun 26, 2024
How To Test A Pool Motor Capacitor

How to Test a Pool Motor Capacitor

A pool motor capacitor is an essential component of your pool's motor system, responsible for storing electrical energy and providing a boost to the motor when needed. However, like any other electrical component, it can fail over time, causing issues with your pool's motor. In this article, we'll guide you on how to test a pool motor capacitor to identify any potential problems.

Why Test a Pool Motor Capacitor?

Testing a pool motor capacitor is crucial to ensure the proper functioning of your pool's motor. A faulty capacitor can cause a range of issues, including:

  • Reduced motor efficiency: A malfunctioning capacitor can reduce the motor's efficiency, leading to increased energy bills and reduced performance.
  • Motor overheating: A faulty capacitor can cause the motor to overheat, leading to premature wear and tear.
  • Motor failure: In extreme cases, a faulty capacitor can cause the motor to fail completely, resulting in costly repairs or replacement.

Tools Needed

To test a pool motor capacitor, you'll need the following tools:

  • Multimeter: A digital multimeter (DMM) or an analog multimeter is necessary for measuring the capacitor's voltage and capacitance.
  • Capacitor tester: A capacitor tester is a specialized tool designed specifically for testing capacitors. It's optional but recommended for accurate results.
  • Safety gloves and safety glasses: Always wear protective gear when working with electrical components to ensure your safety.

Step-by-Step Testing Procedure

1. Disconnect Power to the Motor

Before starting the test, ensure the power to the motor is disconnected. Switch off the circuit breaker or remove the fuse to prevent any accidental startups.

2. Identify the Capacitor

Locate the capacitor in your pool motor system. It's usually a cylindrical or rectangular component with two or three terminals.

3. Measure the Capacitor's Voltage

Using your multimeter, set it to the voltage measurement mode (V). Touch the leads to the capacitor's terminals, making sure to respect the polarity (if marked). Take note of the voltage reading.

4. Measure the Capacitor's Capacitance

Using your multimeter, set it to the capacitance measurement mode (F or μF). Touch the leads to the capacitor's terminals, following the same polarity rules as before. Take note of the capacitance reading.

5. Compare the Readings to the Manufacturer's Specifications

Consult your pool motor's manual or the manufacturer's website to find the recommended voltage and capacitance ratings for the capacitor. Compare your readings to these specifications.

6. Perform a Visual Inspection

Visually inspect the capacitor for signs of damage, such as:

  • Swelling or bulging: If the capacitor is swollen or bulging, it's likely faulty.
  • Leaking or corrosion: Check for signs of leakage or corrosion around the terminals or casing.
  • Burn marks or discoloration: Look for burn marks or discoloration on the capacitor's surface or terminals.

Interpreting the Results

If your readings are within the manufacturer's specifications, the capacitor is likely functioning properly. However, if your readings deviate significantly from the recommended values, it may indicate a faulty capacitor.

In case of a faulty capacitor, consider replacing it with a new one that meets the manufacturer's specifications.


Testing a pool motor capacitor is a relatively simple process that can help you identify potential issues before they cause more serious problems. By following this guide, you'll be able to diagnose and potentially replace a faulty capacitor, ensuring your pool's motor runs efficiently and safely.

Remember to always exercise caution when working with electrical components, and consult a professional if you're unsure about any aspect of the testing procedure.