Raypak Professional Heat Pump Diagnostic Guide
Want a guided diagnosis? Open the Raypak Heat Pump Troubleshooter.
Raypak Professional Heat Pump Diagnostic Guide
Read and record the front-panel code before calling for service. Several entries are operating states rather than failures. Refrigerant-pressure faults and repeated lockouts require qualified HVAC service after basic water-flow checks.
Safety: Disconnect electrical power and follow the manual before opening equipment. Gas, combustion, line-voltage, pressurized-water, and refrigerant work belongs to qualified service personnel.
Control-board codes
| Display or symptom | What it means | Manual-backed check |
|---|---|---|
| OFF | The programmed setpoint is below 50°F. | Raise the setpoint if heating is intended. |
| LP | Low refrigerant, a faulty low-pressure control, or cold ambient air. | Confirm ambient conditions; refrigerant and pressure-control diagnosis requires qualified service. |
| LP3 | Three LP faults occurred in one call for heat. | The unit shut down for protection; call for service. |
| HP | Low water flow or a faulty high-pressure control. | Check pump operation, valves, baskets, filter condition, and backwash if appropriate. |
| HP6 | Six HP faults occurred in one call for heat. | The unit shut down for protection; restore proper flow and call for service if it remains. |
| PSd | The water-temperature sensor is open or defective. | Inspect the sensor circuit and replace the sensor if confirmed faulty. |
| dSd | The suction-line temperature sensor is open or defective. | Inspect the sensor circuit; qualified service should replace it if faulty. |
| FLO | No flow proof. | Check that the filter is not in backwash, the pump is running, the filter is clean, the pump has water, and the flow switch works. |
| FL3 | Three FLO faults occurred in one call for heat. | The unit shut down for protection; correct water flow and call for service if it remains. |
| FS / FS5 | Defrost is active, or five defrost cycles caused a protective shutdown. | FS alone is an operating state. FS5 requires service if ambient and airflow conditions are normal. |
| COL / HEA | The unit is cooling or heating. | No repair is indicated. |
| HOT | A fault occurred during cooling. | Record operating conditions and call qualified service. |
| -- | Both keypad buttons are being pressed. | Free the buttons; replace the keypad if the condition remains. |
Source and model boundary
Source: Raypak Professional Series PS10353–PS10355 Heat Pump Installation and Operation Manual, Control Board Fault Codes. This guide summarizes only the listed model family. Confirm the model number and use the current manufacturer manual before service.