Jandy Pool Heater Error Code 9: How to Fix It
Medium 30-60 minutes Medium Severity
Verified June 2026
- Error Code
- 9
- 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
- Phillips screwdriver
- Multimeter
- Air relief valve tool (if needed)
How to Fix Error Code 9
-
Check for Tripped High-Limit Switch
Ensure power to the heater is off before accessing the control board. -
Inspect Water Flow and Valves
Turn off pump before adjusting valves. -
Purge Air from the System
Use caution when opening air relief valve; hot water may escape. -
Clean the Pressure Switch Tube
Ensure heater is off and cool before handling components. -
Test the Pressure Switch Continuity
Disconnect power to the heater before testing wires. -
Replace the Pressure Switch
Use only a Jandy-compatible pressure switch to ensure proper function.
Parts You May Need
Pressure Switch
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Pressure Switch
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Pressure Switch
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Pressure Switch
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When to Call a Professional
If you have checked water flow, purged air, and replaced the pressure switch and the error persists, contact a pool heater technician. There may be internal control board issues or a blocked heat exchanger requiring professional service.Frequently Asked Questions
What does error code 9 mean on my Jandy pool heater?
Error code 9 indicates a pressure switch fault, meaning the heater is not sensing adequate water flow. This can be caused by low pump speed, closed valves, dirty filter, air in the system, or a faulty pressure switch.
How do I reset my Jandy heater after error code 9?
First, fix the underlying issue (e.g., clean filter, open valves). Then turn off the heater breaker for 30 seconds and turn it back on. If the error returns, follow troubleshooting steps.
Can low water level cause error code 9?
Yes, if the pool water level is too low, the pump may lose prime and fail to provide sufficient flow, triggering the pressure switch fault. Check and fill the pool if needed.
How much does it cost to replace a Jandy pressure switch?
A replacement pressure switch costs around $20-$50. If you hire a technician, labor may add $100-$200 depending on your area.
Is it safe to bypass the pressure switch?
No, bypassing the pressure switch can allow the heater to operate without proper water flow, leading to overheating, heat exchanger damage, or fire hazard. Always fix the root cause.