AstralPool
AstralPool 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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E01
Heater shows E01 and will not start; often on heat pump models.
Low Refrigerant Pressure / Low-Pressure Switch Open (Heat Pump)
E02
Heat pump heater shows E02 and stops; unit may be very hot to touch.
High Refrigerant Pressure / High-Pressure Switch Open (Heat Pump)
E03
Heat pump heater shows E03; unit may run but not heat effectively.
Evaporator Temperature Sensor Fault
E04
Heat pump heater shows E04 and stops; may occur in cold, humid conditions.
Defrost Sensor / Defrost Protection Fault
E05
Heat pump heater shows E05; unit may not start the compressor.
Compressor Overload / Thermal Protection
E06
Heat pump heater shows E06; water temperature reading is erratic.
Water Inlet Temperature Sensor Fault (Heat Pump)
E07
Heat pump heater shows E07; unit may shut down unexpectedly.
Water Outlet Temperature Sensor Fault (Heat Pump)
E08
Heat pump heater shows E08; unit may not respond to commands.
Communication Fault Between Display and Main Board
E09
Heat pump heater shows E09; unit may trip breakers or not start.
Current Protection / Overcurrent Fault
F1
Heater shows F1 and stops; may occur intermittently during operation.
Flow Switch Open During Run
F2
Heater displays F2 and will not start; often after wiring changes or new automation install.
External Control / Thermostat Input Fault
F3
Heater shows F3; fan may run but ignition does not occur.
Ignition Lockout (Retries Exceeded)
F4
Heater displays F4; may occur immediately after start command.
Limit String Open (Safety Chain Open)
F5
Heater shows F5 and shuts down; may be associated with strong wind conditions.
Flame Proving / Flame Signal Weak
F6
Heater displays F6; fan may not start or may start then stop quickly.
Fan Motor / Fan Proving Fault
F7
Heater shows F7; may be associated with very low ambient temperatures.
Freeze Protection / Low Temperature Fault
F8
Heater displays F8 and will not respond to keypad inputs.
Keypad / User Interface Fault
F9
Heater shows F9; may occur after incorrect wiring or polarity issues.
Power Supply / Line Voltage Fault
H1
Heater will not start; display shows H1 shortly after a call for heat.
Water Flow Fault / Low Water Flow
H2
Heater attempts to ignite but shuts down with H2 error on the display.
Ignition Failure / No Flame Detected
H3
Heater starts then quickly shuts down with H3 error; may cycle on and off repeatedly.
Flame Loss During Operation
H4
Heater locks out with H4 error; fan may run briefly then stop (on forced-draft models).
Air Pressure Switch / Fan Proving Fault
H5
Heater displays H5 and will not fire; may occur after long run times.
High Limit Temperature Fault
H6
Heater shows H6 and shuts down; may occur during very hot operation.
Exhaust Overheat / Flue Temperature Fault
H7
Heater displays H7 and will not start; no ignition attempt is heard.
Water Temperature Sensor (NTC) Fault
H8
Heater shows H8; temperature reading on display is obviously wrong (e.g., 0°C or 99°C constantly).
Outlet Temperature Sensor / Differential Fault
H9
Heater displays H9 and will not fire; may occur after a power surge or lightning event.
Internal Control Board Fault
Symptom
Heat pump heater ices up excessively on the outdoor coil and stops heating.
Excessive Frost / Defrost Failure
Symptom
Heat pump heater runs but fan does not spin, or spins very slowly.
Outdoor Fan Motor Failure (Heat Pump)
Symptom
Heater causes noticeable vibration or rattling noises in the equipment area.
Mechanical Vibration / Loose Components
Symptom
Heater display works but buttons do not respond or respond intermittently.
Keypad Button Failure
Symptom
Heater emits a strong gas smell around the unit, especially at startup.
Gas Leak or Incomplete Combustion
Symptom
Heater fan runs but there is no ignition sound or flame, and no error code is displayed.
No Ignition Command / Control Logic Issue
Symptom
Heater is leaking water from the base or inside the cabinet.
Internal Water Leak
Symptom
Heater makes loud banging or popping noises during operation.
Kettling / Boiling in Heat Exchanger
Symptom
Heater runs but occasionally shuts down when the pump speed is reduced (variable-speed pump).
Flow Sensitivity with Variable-Speed Pump
Symptom
Heater runs but pool does not reach set temperature or heats very slowly.
Insufficient Heating Capacity / Performance Issue
Symptom
Heater starts then shuts off after a few minutes without showing an error code.
Short Cycling / Premature Shutdown
Symptom
Heater trips the electrical breaker shortly after starting.
Electrical Short or Overload
Symptom
Heater will not start at all; display is blank and no lights are on.
No Power to Heater
Symptom
Soot or black staining is visible around the flue terminal or on the heater casing.
Sooting / Incomplete Combustion
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| E01 |
Heater shows E01 and will not start; often on heat pump models.
|
Low Refrigerant Pressure / Low-Pressure Switch Open (Heat Pump) | View Details |
| E02 |
Heat pump heater shows E02 and stops; unit may be very hot to touch.
|
High Refrigerant Pressure / High-Pressure Switch Open (Heat Pump) | View Details |
| E03 |
Heat pump heater shows E03; unit may run but not heat effectively.
|
Evaporator Temperature Sensor Fault | View Details |
| E04 |
Heat pump heater shows E04 and stops; may occur in cold, humid conditions.
|
Defrost Sensor / Defrost Protection Fault | View Details |
| E05 |
Heat pump heater shows E05; unit may not start the compressor.
|
Compressor Overload / Thermal Protection | View Details |
| E06 |
Heat pump heater shows E06; water temperature reading is erratic.
|
Water Inlet Temperature Sensor Fault (Heat Pump) | View Details |
| E07 |
Heat pump heater shows E07; unit may shut down unexpectedly.
|
Water Outlet Temperature Sensor Fault (Heat Pump) | View Details |
| E08 |
Heat pump heater shows E08; unit may not respond to commands.
|
Communication Fault Between Display and Main Board | View Details |
| E09 |
Heat pump heater shows E09; unit may trip breakers or not start.
|
Current Protection / Overcurrent Fault | View Details |
| F1 |
Heater shows F1 and stops; may occur intermittently during operation.
|
Flow Switch Open During Run | View Details |
| F2 |
Heater displays F2 and will not start; often after wiring changes or new automation install.
|
External Control / Thermostat Input Fault | View Details |
| F3 |
Heater shows F3; fan may run but ignition does not occur.
|
Ignition Lockout (Retries Exceeded) | View Details |
| F4 |
Heater displays F4; may occur immediately after start command.
|
Limit String Open (Safety Chain Open) | View Details |
| F5 |
Heater shows F5 and shuts down; may be associated with strong wind conditions.
|
Flame Proving / Flame Signal Weak | View Details |
| F6 |
Heater displays F6; fan may not start or may start then stop quickly.
|
Fan Motor / Fan Proving Fault | View Details |
| F7 |
Heater shows F7; may be associated with very low ambient temperatures.
|
Freeze Protection / Low Temperature Fault | View Details |
| F8 |
Heater displays F8 and will not respond to keypad inputs.
|
Keypad / User Interface Fault | View Details |
| F9 |
Heater shows F9; may occur after incorrect wiring or polarity issues.
|
Power Supply / Line Voltage Fault | View Details |
| H1 |
Heater will not start; display shows H1 shortly after a call for heat.
|
Water Flow Fault / Low Water Flow | View Details |
| H2 |
Heater attempts to ignite but shuts down with H2 error on the display.
|
Ignition Failure / No Flame Detected | View Details |
| H3 |
Heater starts then quickly shuts down with H3 error; may cycle on and off repeatedly.
|
Flame Loss During Operation | View Details |
| H4 |
Heater locks out with H4 error; fan may run briefly then stop (on forced-draft models).
|
Air Pressure Switch / Fan Proving Fault | View Details |
| H5 |
Heater displays H5 and will not fire; may occur after long run times.
|
High Limit Temperature Fault | View Details |
| H6 |
Heater shows H6 and shuts down; may occur during very hot operation.
|
Exhaust Overheat / Flue Temperature Fault | View Details |
| H7 |
Heater displays H7 and will not start; no ignition attempt is heard.
|
Water Temperature Sensor (NTC) Fault | View Details |
| H8 |
Heater shows H8; temperature reading on display is obviously wrong (e.g., 0°C or 99°C constantly).
|
Outlet Temperature Sensor / Differential Fault | View Details |
| H9 |
Heater displays H9 and will not fire; may occur after a power surge or lightning event.
|
Internal Control Board Fault | View Details |
| – |
Heat pump heater ices up excessively on the outdoor coil and stops heating.
|
Excessive Frost / Defrost Failure | View Details |
| – |
Heat pump heater runs but fan does not spin, or spins very slowly.
|
Outdoor Fan Motor Failure (Heat Pump) | View Details |
| – |
Heater causes noticeable vibration or rattling noises in the equipment area.
|
Mechanical Vibration / Loose Components | View Details |
| – |
Heater display works but buttons do not respond or respond intermittently.
|
Keypad Button Failure | View Details |
| – |
Heater emits a strong gas smell around the unit, especially at startup.
|
Gas Leak or Incomplete Combustion | View Details |
| – |
Heater fan runs but there is no ignition sound or flame, and no error code is displayed.
|
No Ignition Command / Control Logic Issue | View Details |
| – |
Heater is leaking water from the base or inside the cabinet.
|
Internal Water Leak | View Details |
| – |
Heater makes loud banging or popping noises during operation.
|
Kettling / Boiling in Heat Exchanger | View Details |
| – |
Heater runs but occasionally shuts down when the pump speed is reduced (variable-speed pump).
|
Flow Sensitivity with Variable-Speed Pump | View Details |
| – |
Heater runs but pool does not reach set temperature or heats very slowly.
|
Insufficient Heating Capacity / Performance Issue | View Details |
| – |
Heater starts then shuts off after a few minutes without showing an error code.
|
Short Cycling / Premature Shutdown | View Details |
| – |
Heater trips the electrical breaker shortly after starting.
|
Electrical Short or Overload | View Details |
| – |
Heater will not start at all; display is blank and no lights are on.
|
No Power to Heater | View Details |
| – |
Soot or black staining is visible around the flue terminal or on the heater casing.
|
Sooting / Incomplete Combustion | View Details |
No matching codes found
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