Raypak
Raypak 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
Display shows 'AO' and heater will not fire; may indicate air flow or venting issue on some Raypak models.
Air Flow / Vent Obstruction Fault
AO2
Display shows 'AO2' and heater shuts down; may indicate secondary air/vent fault.
Secondary Air Flow Fault
AO3
Display shows 'AO3' and heater will not start; may be associated with intake air temperature or sensor fault.
Combustion Air Temperature / Sensor Fault
BDS
Display shows 'BDS' and heater will not start; blower may not run on fan‑assisted models.
Blower Draft Switch / Air Proving Fault
FS
Display shows 'FS' and heater will not fire or shuts down shortly after starting.
Flame Sensor / Flame Safeguard Fault
GVC
Display shows 'GVC' and heater will not fire; may indicate gas valve circuit fault.
Gas Valve Circuit Error
HLS
Display shows 'HLS' and heater shuts down or will not fire.
High Limit Switch Open
IF
Display shows 'IF' and heater attempts to light but fails; you may hear clicking or see ignition attempts.
Ignition Failure
IGN
Display shows 'IGN' and heater cycles through ignition attempts without staying lit.
Ignition Lockout
LO
Display shows 'LO' and heater will not fire or shuts down; may be intermittent.
Low Voltage / Line Voltage Fault
PS
Display shows 'PS' and heater will not fire; blower or pump may run briefly then stop.
Water Pressure Switch Open
RAY
Control displays 'RAY' and heater will not fire or respond to thermostat calls.
Control Board Initialization / Standby Display
ROL
Display shows 'ROL' and heater locks out; burner may have lit briefly before shutdown.
Rollout Switch Tripped
ROL1
Display shows 'ROL1' and heater locks out; indicates first rollout circuit open.
Primary Rollout Switch Open
ROL2
Display shows 'ROL2' and heater locks out; indicates secondary rollout circuit open.
Secondary Rollout Switch Open
SEN
Display shows 'SEN' and heater will not operate; may indicate general sensor circuit fault.
Sensor Circuit Error
SFS
Display shows 'SFS' and heater will not fire; may occur on models with stack flue sensor.
Stack Flue Sensor Overtemperature
SFS2
Display shows 'SFS2' and heater locks out; indicates secondary flue temperature fault.
Secondary Stack Flue Sensor Fault
SNS
Display shows 'SNS' and heater will not fire; temperature reading may be erratic or blank.
Water Temperature Sensor Failure
SPK
Display shows 'SPK' and heater repeatedly sparks without establishing flame.
Spark Ignition Failure
SWO
Display shows 'SWO' and heater will not respond to keypad inputs.
Keypad / Switch Overlay Fault
TCO
Display shows 'TCO' and heater shuts down; may reset after cooling.
Thermal Cutoff Open
Symptom
Corrosion or rust visible on burners, heat exchanger, or inside cabinet.
Corrosion from Chemical or Environmental Exposure
Symptom
Heater cabinet or nearby surfaces become excessively hot to the touch during operation.
Overheating Cabinet / Poor Ventilation
Symptom
Heater display is on but unit will not fire; no clicking, no blower, no ignition attempts.
No Call for Heat / Safety Circuit Open
Symptom
Heater display shows erratic or obviously incorrect water temperatures.
Temperature Sensing / Calibration Error
Symptom
Heater emits a strong gas smell around the unit, especially near the gas valve or piping.
Gas Leak at Heater
Symptom
Heater frequently reaches set temperature then overshoots or undershoots before cycling.
Temperature Control Overshoot / Hysteresis Issue
Symptom
Heater is very noisy – loud blower, rattling, or vibration during operation.
Mechanical Vibration / Blower Noise
Symptom
Heater makes loud banging or popping noises during operation.
Kettling / Boiling in Heat Exchanger
Symptom
Heater runs but then shuts off when pump speed is reduced (on variable‑speed pump systems).
Flow‑Related Shutdown with Variable‑Speed Pump
Symptom
Heater runs but water does not heat adequately or takes excessively long to reach set temperature.
Insufficient Heat Output
Symptom
Heater shuts down when it rains or after heavy wind; may restart when dry or calm.
Weather‑Related Nuisance Shutdown
Symptom
Heater starts but shuts off after a few seconds to a minute; may cycle repeatedly.
Short Cycling / Flame Dropout
Symptom
Heater trips the electrical breaker when it tries to start.
Electrical Short / Overcurrent
Symptom
Heater will not start at all – no display, no lights, no sounds.
No Power to Heater
Symptom
Soot or black staining visible on top of heater or around vent outlet.
Sooting / Incomplete Combustion
Symptom
Water leaking from plumbing connections at the heater inlet or outlet.
External Manifold / Union Leak
Symptom
Water leaking from the bottom of the heater cabinet.
Internal Water Leak
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| AO |
Display shows 'AO' and heater will not fire; may indicate air flow or venting issue on some Raypak models.
|
Air Flow / Vent Obstruction Fault | View Details |
| AO2 |
Display shows 'AO2' and heater shuts down; may indicate secondary air/vent fault.
|
Secondary Air Flow Fault | View Details |
| AO3 |
Display shows 'AO3' and heater will not start; may be associated with intake air temperature or sensor fault.
|
Combustion Air Temperature / Sensor Fault | View Details |
| BDS |
Display shows 'BDS' and heater will not start; blower may not run on fan‑assisted models.
|
Blower Draft Switch / Air Proving Fault | View Details |
| FS |
Display shows 'FS' and heater will not fire or shuts down shortly after starting.
|
Flame Sensor / Flame Safeguard Fault | View Details |
| GVC |
Display shows 'GVC' and heater will not fire; may indicate gas valve circuit fault.
|
Gas Valve Circuit Error | View Details |
| HLS |
Display shows 'HLS' and heater shuts down or will not fire.
|
High Limit Switch Open | View Details |
| IF |
Display shows 'IF' and heater attempts to light but fails; you may hear clicking or see ignition attempts.
|
Ignition Failure | View Details |
| IGN |
Display shows 'IGN' and heater cycles through ignition attempts without staying lit.
|
Ignition Lockout | View Details |
| LO |
Display shows 'LO' and heater will not fire or shuts down; may be intermittent.
|
Low Voltage / Line Voltage Fault | View Details |
| PS |
Display shows 'PS' and heater will not fire; blower or pump may run briefly then stop.
|
Water Pressure Switch Open | View Details |
| RAY |
Control displays 'RAY' and heater will not fire or respond to thermostat calls.
|
Control Board Initialization / Standby Display | View Details |
| ROL |
Display shows 'ROL' and heater locks out; burner may have lit briefly before shutdown.
|
Rollout Switch Tripped | View Details |
| ROL1 |
Display shows 'ROL1' and heater locks out; indicates first rollout circuit open.
|
Primary Rollout Switch Open | View Details |
| ROL2 |
Display shows 'ROL2' and heater locks out; indicates secondary rollout circuit open.
|
Secondary Rollout Switch Open | View Details |
| SEN |
Display shows 'SEN' and heater will not operate; may indicate general sensor circuit fault.
|
Sensor Circuit Error | View Details |
| SFS |
Display shows 'SFS' and heater will not fire; may occur on models with stack flue sensor.
|
Stack Flue Sensor Overtemperature | View Details |
| SFS2 |
Display shows 'SFS2' and heater locks out; indicates secondary flue temperature fault.
|
Secondary Stack Flue Sensor Fault | View Details |
| SNS |
Display shows 'SNS' and heater will not fire; temperature reading may be erratic or blank.
|
Water Temperature Sensor Failure | View Details |
| SPK |
Display shows 'SPK' and heater repeatedly sparks without establishing flame.
|
Spark Ignition Failure | View Details |
| SWO |
Display shows 'SWO' and heater will not respond to keypad inputs.
|
Keypad / Switch Overlay Fault | View Details |
| TCO |
Display shows 'TCO' and heater shuts down; may reset after cooling.
|
Thermal Cutoff Open | View Details |
| – |
Corrosion or rust visible on burners, heat exchanger, or inside cabinet.
|
Corrosion from Chemical or Environmental Exposure | View Details |
| – |
Heater cabinet or nearby surfaces become excessively hot to the touch during operation.
|
Overheating Cabinet / Poor Ventilation | View Details |
| – |
Heater display is on but unit will not fire; no clicking, no blower, no ignition attempts.
|
No Call for Heat / Safety Circuit Open | View Details |
| – |
Heater display shows erratic or obviously incorrect water temperatures.
|
Temperature Sensing / Calibration Error | View Details |
| – |
Heater emits a strong gas smell around the unit, especially near the gas valve or piping.
|
Gas Leak at Heater | View Details |
| – |
Heater frequently reaches set temperature then overshoots or undershoots before cycling.
|
Temperature Control Overshoot / Hysteresis Issue | View Details |
| – |
Heater is very noisy – loud blower, rattling, or vibration during operation.
|
Mechanical Vibration / Blower Noise | View Details |
| – |
Heater makes loud banging or popping noises during operation.
|
Kettling / Boiling in Heat Exchanger | View Details |
| – |
Heater runs but then shuts off when pump speed is reduced (on variable‑speed pump systems).
|
Flow‑Related Shutdown with Variable‑Speed Pump | View Details |
| – |
Heater runs but water does not heat adequately or takes excessively long to reach set temperature.
|
Insufficient Heat Output | View Details |
| – |
Heater shuts down when it rains or after heavy wind; may restart when dry or calm.
|
Weather‑Related Nuisance Shutdown | View Details |
| – |
Heater starts but shuts off after a few seconds to a minute; may cycle repeatedly.
|
Short Cycling / Flame Dropout | View Details |
| – |
Heater trips the electrical breaker when it tries to start.
|
Electrical Short / Overcurrent | View Details |
| – |
Heater will not start at all – no display, no lights, no sounds.
|
No Power to Heater | View Details |
| – |
Soot or black staining visible on top of heater or around vent outlet.
|
Sooting / Incomplete Combustion | View Details |
| – |
Water leaking from plumbing connections at the heater inlet or outlet.
|
External Manifold / Union Leak | View Details |
| – |
Water leaking from the bottom of the heater cabinet.
|
Internal Water Leak | View Details |
No matching codes found
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