Many clients have asked me this question. Why is my hot tub not heating up? I have talked to people about this process over the phone and sent them a list of information on how to test the spa heater themselves. I do not normally recommend that an end user attempt to troubleshoot their own spa. Working with electricity can be dangerous and working with electricity and water can be deadly. It is always recommended to contact a qualified service technician to troubleshoot any problems. With that said, many people are more than capable of troubleshooting their own spa heater and this guide will help you.
Hot tub and spa heater troubleshooting guide
An easy-to-follow hot tub and spa heater troubleshooting guide. Troubleshooting a spa heater can be a simple procedure if you have the right tools.
Note: This troubleshooting guide is intended for trained spa service professionals. It is not recommended that the spa owner troubleshoot their own spa.
The tools you will need to have are:
A multimeter, to check the voltage, and a clamp on the ammeter, to check the ampere draw on the element. You cannot accurately troubleshoot a spa heating element without these tools.
Multimeter – Used to test the voltage at the terminals of the heating element.
Amp Meter – Used to check the amp draw of the heating element.
You will also need several hand tools. Screwdrivers, pliers, spanners, etc.
Note: The spa must be filled with water and in normal operating condition to perform these tests.
To test the heating element, you must: Check the voltage across the heating element
1. Turn off the spa. (This means turning off the spa’s voltage source at the circuit breaker or disconnecting).
2. Open the equipment area and locate the heater assembly.
3. Open the spa heater assembly to expose the heater terminals.
4. Make sure all other wires and connections are clear of the heater terminals.
5. Open the filter housing of the spa and remove the filter. Replace the filter cap and secure it for operation.
6. Double check the area around the heater terminals to make sure you have access to the terminals with the multimeter probes, without the risk of touching other contacts.
7. Remember, when you reapply power to the spa, it will be running on 240 volts of electricity. Water and electricity don’t mix.
8. Make sure there is no water near the terminals where you will be working. Also, make sure you are not kneeling or standing in the water while testing the voltage at the heater terminals.
9. Reapply power to the spa and turn up the thermostat to turn on the heater. Listen to the spa to see if the operation sounds normal.
10. Turn on the multimeter and plug the probes into the meter as instructed in the meter instructions. It will be testing voltage.
11. Carefully place a probe on one of the element’s terminals.
12. Carefully place the second probe on the other terminal of the heater.
13. Read your multimeter to see the voltage across the element.
14. Remove both probes and write down the voltage you read on your test.
15. Turn off the spa. If you received “0” volts at the heater terminal, your problem is most likely not the heater element. If you received the correct voltage at the heater terminals, you should now check the amp draw on your heater.
Check the amp draw on the heating element
1. Turn off the spa. (This means turning off the spa’s voltage source at the circuit breaker or disconnecting).
2. Find the wires that connect to the spa heater terminals.
3. Clamp a wire that goes to your heating element, with your ammeter.
4. Make sure all cables are tight and safe for operation.
5. Reapply power to your spa and turn up the thermostat to turn on the heater.
6. Check the ammeter to see if the heating element is drawing amps.
7. Turn off the spa.
8. Write down the amp reading on your ammeter. If you received an amperage reading from your heater. Your heating element is working. You need to look elsewhere for trouble.
* If you received the proper voltage at the heater terminals, but did not receive an amperage reading when the spa was running, the heater element is faulty.
What to do if the heating element works fine during these tests, but does not heat the spa, during normal operation. Remember step 5 in the voltage test. You removed the filter. Check the condition of the filter, run the spa for 24 hours without the filter in place to see if the spa heats normally. If the spa heats normally without a filter, replace the filter with a new one.
Now keep in mind that every hot tub / spa is different. If you have a digital system, make a note of the error codes displayed. The new digital systems in today’s spas will do much of the troubleshooting for you if you know what it’s telling you, but let’s save that for another article.