Pool Heater Error Codes
Decode fault messages and diagnostic codes for all heater brands
Quick Answer
Pool heater error codes are safety shutdowns protecting equipment and users. Common codes include E01-E05 (ignition failures), LO/FLO (low flow), HI/HL (high limit), and ERR (general faults). While 30% are simple flow issues you can fix, most require professional diagnosis to safely resolve electrical, gas, or sensor problems.
Professional service recommended for this issue
Understanding Pool Heater Error Codes
Why Error Codes Exist
- • Safety protection: Prevent dangerous conditions
- • Equipment preservation: Avoid costly damage
- • Diagnostic aid: Pinpoint specific problems
- • Regulatory compliance: Meet safety standards
- • User notification: Alert to service needs
Code Display Types
- • Digital displays: Show alphanumeric codes
- • LED sequences: Flash patterns indicate errors
- • Service lights: Simple on/off indicators
- • Remote displays: Automation system messages
- • Combination codes: Multiple issues shown
Local Area Note: During extreme Texas weather in Southlake, Westlake, and surrounding areas, error codes spike due to power fluctuations, gas pressure variations, and rapid temperature changes affecting sensors.
Common Error Codes by Category
Flow & Pressure Errors
Common Codes:
- LO/FLO: Low water flow detected
- PS/PRS: Pressure switch open
- E06: Flow sensor fault
- FLS: Flow switch stuck
Typical Causes:
- • Dirty filter (most common)
- • Pump not running full speed
- • Closed or restricted valves
- • Air in system
Quick Fix: Clean filter, check pump speed, verify all valves open
Temperature & Limit Errors
Common Codes:
- HI/HL: High limit exceeded
- E01/HOT: Overheating detected
- LIM: Limit switch tripped
- SEN: Sensor reading error
Typical Causes:
- • Low water flow
- • Scaled heat exchanger
- • Failed temperature sensor
- • Bypass valve issues
Safety Alert: Temperature errors indicate overheating risk - professional service required
Ignition & Combustion Errors
Common Codes:
- E02-E05: Ignition sequence failures
- IGN: Ignitor fault
- FLM: No flame detected
- GAS: Gas valve error
Typical Causes:
- • Dirty flame sensor
- • Failed ignitor
- • Gas supply issues
- • Control board problems
Gas Safety: Ignition errors involve gas systems - professional required
Electrical & Control Errors
Common Codes:
- E00/ERR: General control fault
- COM: Communication error
- MEM: Memory/EEPROM fault
- POW: Power supply issue
Typical Causes:
- • Power surges (common in Texas)
- • Control board failure
- • Loose connections
- • Water damage to electronics
Electrical Safety: Control errors require qualified technician diagnosis
Error Codes by Heater Brand
Hayward Error Codes
- LO: Low water flow/pressure
- IF: Ignition failure
- CE: Communication error
- AO: Air flow restriction (heat pumps)
- BO: Bypass operation active
Pentair/Sta-Rite Codes
- E01-E05: Ignition sequence errors
- E06: Flow/pressure switch
- ERR: System error
- AGS: Automatic gas shutoff
- SFS: Stack flue sensor
Jandy/Zodiac Codes
- Fault 1-3: Temperature sensor faults
- Fault 4: High limit fault
- Fault 5: Stack flue fault
- FLO: Flow detection error
- IGN: Ignition control fault
Raypak/Rheem Codes
- SNS: Sensor failure
- HLS: High limit switch
- ROL: Rollout switch open
- PRS: Pressure switch stuck
- FAN: Fan proving error
Note: Error codes vary by model year and series. Always consult your specific manual or contact manufacturer support for exact code meanings.
Heater Error Code Safety
- •Error codes indicate safety shutdowns - never bypass or disable them
- •Gas-related errors require immediate professional attention
- •Repeated errors can damage expensive components
- •Some errors indicate carbon monoxide or fire risks
- •Electrical errors may cause shock hazards
- •Always turn off heater power before any inspection
If you smell gas: EVACUATE immediately and call your gas company's emergency line
DIY Error Code Resolution
Safe DIY Fixes (30% of errors)
- ✓ Clean dirty filters causing flow errors
- ✓ Open closed valves restricting flow
- ✓ Reset after power outages
- ✓ Clear debris from heater area
- ✓ Check circuit breakers
- ✓ Verify gas valve is open
Professional Only (70% of errors)
- ✗ Any gas system errors (E02-E05, IGN)
- ✗ Temperature sensor failures
- ✗ Control board errors (ERR, COM)
- ✗ Electrical component failures
- ✗ Recurring errors after reset
- ✗ Multiple simultaneous errors
Basic Reset Procedure:
- Turn heater OFF at control panel
- Turn OFF power at circuit breaker
- Wait 30 seconds minimum
- Turn breaker back ON
- Turn heater ON and monitor
- If error returns, call professional
Professional Error Code Diagnosis
Record the Exact Error Code
Document the specific code, flashing pattern, or LED sequence
⚠️ Warning: Error codes indicate safety shutdowns - do not bypass or ignore them
Check Basic System Conditions
Verify fundamental requirements before advanced troubleshooting
⚠️ Warning: Many error codes result from simple flow or pressure issues
Reset and Monitor Heater
Clear error and observe restart sequence
⚠️ Warning: If error returns immediately, do not repeatedly reset - call professional
Test Related Components
Check sensors and switches related to error code
⚠️ Warning: Component testing requires electrical knowledge - professionals recommended
Decode Complex Error Patterns
Understand multi-digit codes and LED flash sequences
⚠️ Warning: Complex codes often indicate internal failures requiring professional repair
Professional Diagnosis Required
When DIY troubleshooting reaches its limits
⚠️ Warning: Most error codes require licensed technician for safe resolution
Error Code Repair Costs
🔧 DIY Attempt
⚠️ Risks:
- • Missing serious safety issues requiring professional attention
- • Causing additional damage by incorrect troubleshooting
- • Voiding warranty with improper reset procedures
- • Personal injury from gas or electrical hazards
- • Expensive component damage from repeated errors
👷 Professional Service
✅ Includes:
- • Complete diagnostic testing with professional tools
- • Error code interpretation and root cause analysis
- • Safety system verification and testing
- • Component replacement if needed
- • System calibration and optimization
- • Warranty on repairs and parts
Detailed Cost Breakdown
| Item/Service | Low | High |
|---|---|---|
| Diagnostic service call | $125 | $200 |
| Sensor replacement | $150 | $350 |
| Control board repair/replace | $400 | $800 |
| Ignition component replacement | $200 | $500 |
| Pressure switch replacement | $150 | $300 |
| Total Range | $1025 | $2150 |
💰 Value Tip: CoOpPools offers transparent pricing with no hidden fees. Our worker-owned model means fair prices and invested service.
Prevention Tips
Annual Professional Service
Yearly heater inspection prevents most error-causing failures. Technicians clean sensors, test safety switches, and calibrate controls before problems develop.
Maintain Proper Water Flow
Clean filters monthly and check pump operation. Most pressure-related errors (LO, FLO) result from restricted water flow through the heater.
Monitor Water Chemistry
Keep pH 7.2-7.6 and calcium 200-400 ppm. Poor chemistry causes sensor coating and heat exchanger scaling that trigger temperature errors.
Protect Electrical Components
Install surge protectors and ensure proper grounding. Texas storms cause voltage spikes that damage control boards and sensors.
Regular Sensor Cleaning
Clean flame sensors and thermistors seasonally. Dirty sensors cause false readings that trigger unnecessary error codes.
🏊 Pro Tip: Regular professional maintenance prevents 90% of pool problems.Get your maintenance quote today
This Issue Requires Professional Service
Heater error codes are safety warnings that shouldn't be ignored. Our certified technicians decode all error messages, diagnose root causes, and restore safe heater operation. We service all brands with same-day emergency response.
Mention "heater error codes" when calling for faster service
Related Pool Problems
Heater Won't Ignite
Often RelatedIgnition failures often display E01-E05 error codes
Heater Pressure Switch Error
Often RelatedFLO, LO, and pressure-related error codes
Heater Overheating
Sometimes RelatedHI, HL, and temperature limit error codes
💡 Did You Know? Pool problems often occur together.heater-error-codes can lead to or be caused by these related issues. Understanding the connections helps prevent future problems.