Jandy
Jandy Pool Heaters Error Codes
Complete list of fault codes and troubleshooting guides. Use the search below to find your specific error.
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AO
Heater shows AO and will not fire; blower may not start or may run briefly.
Air Flow / Air Pressure Switch Open
AO
On some Jandy models, AO appears intermittently and heater cycles off and on.
Intermittent Air Flow / Pressure Switch Fault
AO2
Heater shows AO2 and will not fire; blower may run continuously or not at all.
Air Flow Fault – Pressure Switch Closed/Open at Wrong Time
AO3
Display shows AO3; heater locks out and blower behavior is abnormal.
Air Flow Fault – Blower Proving Error
AO4
Heater displays AO4 and will not start heating cycle.
Air Flow Fault – Pressure Switch State Error
AO5
Display shows AO5; heater may attempt to start but shuts down quickly.
Air Flow Fault – Blower Speed / Proving Timeout
AO6
Display shows AO6; heater fails to complete startup sequence.
Advanced Air Flow Diagnostic Fault
ERR
Display shows generic ERR or error; heater is unresponsive or stuck.
General Control Board Fault
FLO
Display shows FLO or similar flow-related message; heater will not fire.
Water Flow Fault
FS
Display shows FS; heater will not fire or shuts down quickly.
Flame Sense Fault
HLS
Heater displays HLS and shuts down; may restart after cooling.
High Limit Switch Open
HS
Heater displays HS and shuts down; may restart after cooling.
High Temperature Sensor Trip
IF
Heater will not fire; display shows IF (Ignition Failure) after several attempts, blower may run briefly then stop.
Ignition Failure Lockout
IGN
Display shows IGN or ignition error; heater attempts to light but shuts down.
Ignition Sequence Failure
LO
Display shows LO; heater will not fire or shuts down shortly after starting.
Low Water Flow / Pressure Switch Open
ROL
Heater shows ROL or rollout error and will not fire.
Flame Rollout Switch Trip
SERVICE
Display shows SERVICE or SERVICE HEATER; heater may still run or may lock out.
Service Reminder / Non-Specific Fault
SF
Heater display shows SF and will not run; blower does not start.
Safety Fault Lockout
SFS
Display shows SFS or stack flue sensor error; heater may shut down after running briefly.
Flue Gas Temperature Sensor Fault
SNS
Heater displays SNS or sensor error; unit may not fire or may shut down erratically.
Temperature Sensor Fault
Symptom
Heater display is on but blower never starts when heat is called.
Blower Fails to Start
Symptom
Heater display shows incorrect water temperature compared to an external thermometer.
Temperature Sensing Inaccuracy
Symptom
Heater display works but keypad buttons do not respond or respond intermittently.
Keypad / User Interface Failure
Symptom
Heater does not respond to automation system commands (e.g., Jandy AquaLink).
Communication / Remote Control Failure
Symptom
Heater emits soot or black stains around the exhaust or cabinet.
Sooting / Incomplete Combustion
Symptom
Heater frequently shuts down with no code when wind is strong.
Wind-Induced Flame or Pressure Disruption
Symptom
Heater leaks water from the bottom of the cabinet.
Internal Water Leak
Symptom
Heater makes loud banging or popping noises during operation.
Boiling or Delayed Ignition
Symptom
Heater produces a whistling or high-pitched noise when running.
Air or Gas Flow Resonance
Symptom
Heater runs but causes plastic smell or burning odor around the unit.
Overheating of Non-Metal Components
Symptom
Heater runs but water does not reach set temperature; very slow heating.
Insufficient Heat Output
Symptom
Heater shuts off when pump speed is reduced on a variable-speed pump.
Flow-Dependent Shutdown
Symptom
Heater starts and runs for a short time, then shuts off and restarts repeatedly (short cycling).
Short Cycling Operation
Symptom
Heater trips the electrical breaker when starting or during operation.
Electrical Short or Overload
Symptom
Heater vibrates excessively or rattles during operation.
Mechanical Vibration / Loose Components
Symptom
Heater will not start at all; no display, no lights, no blower.
No Power to Heater
Symptom
Strong gas smell near the heater, especially during or after operation.
Gas Leak or Incomplete Combustion
Symptom
Visible rust or corrosion inside the heater cabinet; components appear deteriorated.
Corrosion Damage
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| AO |
Heater shows AO and will not fire; blower may not start or may run briefly.
|
Air Flow / Air Pressure Switch Open | View Details |
| AO |
On some Jandy models, AO appears intermittently and heater cycles off and on.
|
Intermittent Air Flow / Pressure Switch Fault | View Details |
| AO2 |
Heater shows AO2 and will not fire; blower may run continuously or not at all.
|
Air Flow Fault – Pressure Switch Closed/Open at Wrong Time | View Details |
| AO3 |
Display shows AO3; heater locks out and blower behavior is abnormal.
|
Air Flow Fault – Blower Proving Error | View Details |
| AO4 |
Heater displays AO4 and will not start heating cycle.
|
Air Flow Fault – Pressure Switch State Error | View Details |
| AO5 |
Display shows AO5; heater may attempt to start but shuts down quickly.
|
Air Flow Fault – Blower Speed / Proving Timeout | View Details |
| AO6 |
Display shows AO6; heater fails to complete startup sequence.
|
Advanced Air Flow Diagnostic Fault | View Details |
| ERR |
Display shows generic ERR or error; heater is unresponsive or stuck.
|
General Control Board Fault | View Details |
| FLO |
Display shows FLO or similar flow-related message; heater will not fire.
|
Water Flow Fault | View Details |
| FS |
Display shows FS; heater will not fire or shuts down quickly.
|
Flame Sense Fault | View Details |
| HLS |
Heater displays HLS and shuts down; may restart after cooling.
|
High Limit Switch Open | View Details |
| HS |
Heater displays HS and shuts down; may restart after cooling.
|
High Temperature Sensor Trip | View Details |
| IF |
Heater will not fire; display shows IF (Ignition Failure) after several attempts, blower may run briefly then stop.
|
Ignition Failure Lockout | View Details |
| IGN |
Display shows IGN or ignition error; heater attempts to light but shuts down.
|
Ignition Sequence Failure | View Details |
| LO |
Display shows LO; heater will not fire or shuts down shortly after starting.
|
Low Water Flow / Pressure Switch Open | View Details |
| ROL |
Heater shows ROL or rollout error and will not fire.
|
Flame Rollout Switch Trip | View Details |
| SERVICE |
Display shows SERVICE or SERVICE HEATER; heater may still run or may lock out.
|
Service Reminder / Non-Specific Fault | View Details |
| SF |
Heater display shows SF and will not run; blower does not start.
|
Safety Fault Lockout | View Details |
| SFS |
Display shows SFS or stack flue sensor error; heater may shut down after running briefly.
|
Flue Gas Temperature Sensor Fault | View Details |
| SNS |
Heater displays SNS or sensor error; unit may not fire or may shut down erratically.
|
Temperature Sensor Fault | View Details |
| – |
Heater display is on but blower never starts when heat is called.
|
Blower Fails to Start | View Details |
| – |
Heater display shows incorrect water temperature compared to an external thermometer.
|
Temperature Sensing Inaccuracy | View Details |
| – |
Heater display works but keypad buttons do not respond or respond intermittently.
|
Keypad / User Interface Failure | View Details |
| – |
Heater does not respond to automation system commands (e.g., Jandy AquaLink).
|
Communication / Remote Control Failure | View Details |
| – |
Heater emits soot or black stains around the exhaust or cabinet.
|
Sooting / Incomplete Combustion | View Details |
| – |
Heater frequently shuts down with no code when wind is strong.
|
Wind-Induced Flame or Pressure Disruption | View Details |
| – |
Heater leaks water from the bottom of the cabinet.
|
Internal Water Leak | View Details |
| – |
Heater makes loud banging or popping noises during operation.
|
Boiling or Delayed Ignition | View Details |
| – |
Heater produces a whistling or high-pitched noise when running.
|
Air or Gas Flow Resonance | View Details |
| – |
Heater runs but causes plastic smell or burning odor around the unit.
|
Overheating of Non-Metal Components | View Details |
| – |
Heater runs but water does not reach set temperature; very slow heating.
|
Insufficient Heat Output | View Details |
| – |
Heater shuts off when pump speed is reduced on a variable-speed pump.
|
Flow-Dependent Shutdown | View Details |
| – |
Heater starts and runs for a short time, then shuts off and restarts repeatedly (short cycling).
|
Short Cycling Operation | View Details |
| – |
Heater trips the electrical breaker when starting or during operation.
|
Electrical Short or Overload | View Details |
| – |
Heater vibrates excessively or rattles during operation.
|
Mechanical Vibration / Loose Components | View Details |
| – |
Heater will not start at all; no display, no lights, no blower.
|
No Power to Heater | View Details |
| – |
Strong gas smell near the heater, especially during or after operation.
|
Gas Leak or Incomplete Combustion | View Details |
| – |
Visible rust or corrosion inside the heater cabinet; components appear deteriorated.
|
Corrosion Damage | View Details |
No matching codes found
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