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Few things are more frustrating than a hot tub that won’t heat up. You’re ready to relax, but instead you’re sitting in lukewarm water—or worse, cold water.
The good news? Most hot tub heating problems can be diagnosed and fixed with the right parts. Here’s a step-by-step guide to troubleshooting your spa heater.
Common Reasons Your Hot Tub Won’t Heat
1. Tripped Breaker or Power Supply Issue
Always start simple. A tripped breaker or GFCI can cut power to your heater. Reset it, and if it trips again, there may be a deeper issue.
If your breaker keeps tripping, check your heater element or pump—they may be drawing too much power.
2. Faulty Heater Element
The heater element is what physically heats the water. Over time, it can burn out.
Signs:
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Spa runs, but water never gets hot.
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Breaker trips when heater tries to run.
Solution: Replace the heater element. Shop Hot Tub Heater Elements.
3. Bad Temperature or High-Limit Sensor
If your spa’s sensors fail, the system may think the water is hotter than it really is—and refuse to heat.
Solution: Test and replace the temperature sensor or high-limit sensor. Shop Spa Sensors.
4. Circulation Pump Issues
Your heater can’t work if water isn’t moving through it. A failing circulation pump can prevent heating.
Solution: Check the pump for blockages or failure. Shop Spa Circulation Pumps.
5. Control Board Problems
If your control board (the “brain” of your spa) isn’t sending power to the heater, nothing will happen—even if the heater itself is fine.
Solution: Inspect for damage or burnt spots. Shop Spa Control Boards.
Pro Tips for Preventing Heating Problems
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Keep your filters clean so water can flow freely.
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Replace filters every 12–18 months. Shop Spa Filters.
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Don’t run your spa with low water—this can burn out the heater.
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Maintain water chemistry—corrosive water shortens part life.
FAQs About Hot Tub Heating Problems
Q: My jets work but the water stays cold. What’s wrong?
Likely the heater element or sensor. Check both before replacing.
Q: Can I repair a heater element, or do I need to replace it?
Most often, replacement is easier and more reliable than repair.