Jandy Pool Heater Error Code 12: How to Fix It
Medium 30-60 minutes Medium Severity
Verified June 2026
- Error Code
- 12
- Brand
- Jandy
- Product Type
- pool_equipment
- Severity
- Medium
- DIY Difficulty
- Medium
- Estimated Fix Time
- 30-60 minutes
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Tools You'll Need
- Multimeter
- Screwdriver (flathead and Phillips)
- Pool filter cleaning tools (if applicable)
How to Fix Error Code 12
-
Turn Off Power and Gas
Always cut power and gas before servicing to avoid electric shock or gas leaks. -
Check Pool Pump and Filter
-
Inspect Water Flow Switch
-
Test the Flow Switch with a Multimeter
-
Check Wiring and Connections
-
Replace Faulty Flow Switch
Use only approved replacement parts to maintain safety and warranty.
Parts You May Need
Water flow switch
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Water flow switch
Check Price on Amazon
Water flow switch
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Water flow switch
Check Price on Amazon
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When to Call a Professional
If you've replaced the flow switch and the error persists, or if you're uncomfortable working with gas or electrical components, call a certified pool heater technician.Frequently Asked Questions
What does error code 12 mean on a Jandy pool heater?
Error code 12 means the water flow switch is not detecting sufficient water flow through the heater, preventing it from operating.
Can a dirty filter cause error code 12?
Yes, a dirty filter can reduce water flow, causing the flow switch to not close and triggering error code 12.
How do I reset a Jandy pool heater after error 12?
Turn off the heater, fix the flow issue, then turn it back on. Error code 12 usually clears automatically once proper flow is restored.
Where is the water flow switch on a Jandy heater?
It's typically located on the water inlet pipe near the heater, often with a tee fitting and two wires attached.
How much does a Jandy flow switch replacement cost?
The part costs $20-$50, and professional installation adds $100-$200 if you hire a technician.