How To Test Hot Tub Pump With Multimeter: A Step-By-Step Guide

Have you ever found yourself in a situation where you needed to quickly figure out how to test a hot tub pump with a multimeter but have no clue where to begin? Testing the hot tub pump correctly with a multimeter is an important step for ensuring that your hot tub will stay in great condition for years to come. With the right knowledge and a few easy steps, you can check the hot tub pump using a multimeter with ease. In this article, we’ll go over how to test a hot tub pump with a multimeter, as well as explain voltage drops and troubleshooting hot tub pump issues. Let’s jump in!

How to Test Hot Tub Pump with Multimeter

If you own a hot tub, it’s important to regularly check its pump to ensure it is functioning properly. Testing the pump with a multimeter is an effective and fairly simple way to make sure your hot tub pump is working as it should. This guide will walk you through exactly how to use a multimeter to test your hot tub pump, including instructions on measuring the start/run windings, the ground windings and calculating voltage drops. Read on to find out more and securely troubleshoot any potential issues with your hot tub pump.

Set Your Multimeter for AC Voltage Measurement

To set your multimeter for AC voltage measurements, locate the port labeled “VΩmA” or “VΩmA” on your multimeter and select the “Voltage DC/AC” function. At this stage, it is important to also check the input impedance; this should be set to at least 10 MN. Input impedance ensures that small measurements, such as resistance or voltage, will not overload the multimeter.

To set your multimeter to the right range, follow these steps:

1. Make sure the switch, usually located on the left upper side of the multimeter, is set to the “VΩmA” knob.
2. After that, press the “Range” button to select the correct range for your measurement.
3. Use the switch located near the top of the multimeter to select the AC voltage measurement.
4. Finally, turn the knob to the right side to set the desired voltage range.

In order to make a successful measurement, it is important to choose the correct voltage range. Common ranges include 200V (low), 1000V (mid-high), and 10100V (high). The ranges are typically denoted by different marking, therefore pay close attention to the markings when choosing the range.

It is important to note that some old-style multimeters may have a different method of setting the range than the one outlined above. If you have an old-style meter, consult your manual to ensure you have the right setup.

Remember to always use the highest range when testing AC voltage. This will avoid any damage to your multimeter or the device you are testing.

Measuring the Start/Run Windings

Testing the start/run windings of a hot tub pump with a multimeter is a straightforward process. First, make sure to turn off the pump at the breaker or power source, then take your multimeter and set it to AC voltage measurements. Once the multimeter has been set, you can attach the probes to the start/run windings of the pump. You will usually see two or four of these windings, labeled S and R if there are two, or S1, S2, R1, and R2 if there are four. Each pair should read the same voltage. If the voltage readings are different, then the winding may be burned and replacement of the pump is necessary. Be careful when measuring the start/run windings, as electric shock is always possible in these situations. Never measure these windings with more than 50VAC and make sure to check for voltage before touching the pump. If the voltage is present, the windings may be magnetically charged and the current needs to be discharged by a qualified electrician.

Measuring the Ground Windings

Measuring the ground windings of a hot tub pump is one of the most important steps in testing the device, and one of the most difficult to execute. To do this, attach the multimeter’s probes to each of the pump’s ground windings, then slowly increase the range until the multimeter indicates the correct voltage. It’s best to start on the lowest range, then slowly go up until the appropriate voltage is found. Be careful when increasing the range, as tampering with any of the ground wiring may result in an electric shock. If any of these steps feel unsafe, it is best to contact a certified electrician to ensure the work is correctly and safely completed.

When finished, all of the ground windings should measure the same value. If one of the windings reads a significantly higher voltage than the others, it is likely that something is wrong with the ground wiring and needs to be looked into further.

Once all of the ground windings have been tested and the correct voltage has been found, it is important to note the value and move on to the next step — calculating the voltage drop. Usually, the voltage drop during this step should not exceed 3 percent of the total value, so be sure to pay attention to any changes that occur during the process and re-measure as necessary.

Calculating Voltage Drops

Calculating voltage drops on a hot tub pump allows you to check for potential problems. Voltage drops can indicate issues with wiring, connections, fuses, or other components. Follow these steps to check voltage drops on a hot tub pump:

  • Measure the voltage of each winding with the multimeter set to AC.
  • Subtract the highest voltage from the lowest voltage.
  • Divide the result by the highest voltage.
  • Multiply the result by 100 to calculate the voltage drop percentage.

If there is a voltage drop greater than 10%, that indicates a problem with the wiring, connections, or other components. If the voltage drop is less than 10%, then there is no need for further troubleshooting.

Troubleshooting hot tub pump issues can be difficult, but these calculations make it easy to identify potential problems. Problems that can be identified include loose connections, faulty wiring, and blown fuses. If a higher voltage drop is detected, additional testing may be required to determine the cause.

Troubleshooting Hot Tub Pump Issues

Troubleshooting hot tub pump issues can involve many components, and must be done safely and securely. In order to properly identify any hot tub pump problems and find the most appropriate solutions, it is important to use the correct steps:

1. Check the pump’s power supply. Make sure that it is connected to the correct power outlet and that the correct voltage is being supplied.

2. Check the pump’s wiring and connections. Look for any frayed wires or worn cables, and make sure that the connections are properly secured.

3. Inspect the pump’s impeller. Look for any debris or buildup, then clean and lubricate the shaft to make sure the impeller is turning freely.

4. Check the thermal overload protection switch on the pump. Observe whether the switch is tripped and reset it if necessary.

5. Check the pump’s capacitor rating. If necessary, replace the capacitor with a new one with the correct rating.

6. Use a multimeter to take voltage measurements. Measure between the start/run windings, ground windings, and calculate voltage drops.

By taking all of these steps, you should be able to identify any problems with your hot tub pump and make the necessary repairs. Professional assistance may be required if the problems are too complex, or if the pump is in a dangerous or hard-to-reach area.

Frequently Asked Questions

How do you test a hot tub pump?

1. Shut off the power to the hot tub and remove the pump lid.
2. Disconnect the intake from the pump, and remove the four screws from the pump lid.
3. Inspect the impeller for any debris or damage.
4. Check for any blockages in the piping leading to and from the hot tub to the pump.
5. Connect a standard multimeter to the motor leads and take the voltage reading by setting it to the AC voltage setting.
6. Start up the hot tub and measure the current running through the pump.
7. Take amperage reading and compare it against the manufacturer’s specifications.

How do you know if a hot tub pump is bad?

To determine if your hot tub pump is bad, you should first inspect the pump for any visible signs of damage. You should check for broken or cracked components, as well as any corrosion that might have developed. Additionally, if your hot tub pump is making strange noises, such as grinding or humming, this could be a sign that something is wrong. Finally, you should also check that the pump is receiving adequate power from the hot tub’s breaker. If the breaker trips, this could indicate a problem with the pump.

What voltage is a hot tub pump?

The voltage of a hot tub pump depends on the particular make and model. Hot tubs may operate on either 110-120V or 220-240V, so it is important to make sure you check your pump to determine which voltage it requires.

How do you test a 2 speed hot tub pump?

To test a 2 speed hot tub pump, you will need to turn on the hot tub’s power and set the thermostat to the highest temperature. Then, you should use a multimeter to check that the pump is receiving the correct voltage. Next, you will need to start the pump on it’s low speed and the voltage should match that specified in the owner’s manual. If the voltage is correct, you should then start the pump in high speed and check that the voltage increases as expected. Finally, you should also check for any leakage in the pump, as well as check for any vibration or rattling that may indicate an issue with the pump.


The multimeter is a helpful and valuable tool when troubleshooting hot tub pump issues. By measuring start/run windings and ground windings, it is easy to calculate voltage drops and detect potential problems. No matter the issue, testing hot tub pumps with a multimeter helps to maintain the lifespan and effectiveness of the equipment. So, if you ever encounter any hot tub pump issues, remember this article and how to test a hot tub pump with a multimeter.

Eric Schunk

Hi, I'm Eric Schunk, the main author of OchoWorkshop. I've been working in the hot tub industry for over 15 years, and I'm passionate about helping people find the perfect hot tub for their needs. I've written countless articles and guides on hot tubs, from buying guides to maintenance and repair tips. I pride myself on providing accurate, in-depth information that can help you make an informed decision when it comes to buying and maintaining your hot tub.