GENERAL AIRSTAGE | SERVICE AND COMMISSIONING
Rooftop Package Unit Commissioning
Danfoss Controller, Operating Parameters, Alarms and Troubleshooting
Applicable to the single skin PREMIUM / RAQ rooftop range. Instructions are based on the RTPU Commissioning Guide Version 1.4.
1. Pre-Commissioning Checklist
| Check | Requirement |
|---|---|
| Unit identification | Record model, serial number, refrigerant and configuration. |
| Installation | Verify supports, clearances, panels, ductwork, filters and condensate drains. |
| Electrical | Check supply voltage, phase sequence, protective devices, terminations and earthing. |
| Refrigerant circuit | Inspect for leaks, damage and abnormal circuit conditions. |
| Compressor heating | Confirm crankcase-heater operation and initial start delay. |
| External controls | Check remote start, emergency stop, mode inputs and any BMS connection. |
| Airflow | Verify supply fan operation and design airflow against the installation requirements. |
2. Phase Failure Relay
Some rooftop units have adjustable phase-monitoring relays. Two versions are identified in the commissioning guide.
| Dial Colour | Adjustment Type | Guide Recommendation |
|---|---|---|
| Blue | Voltage-based | 30 V undervoltage and overvoltage adjustment |
| Orange | Percentage-based | 12.5% overvoltage and 12.5% undervoltage |
These recommendations relate to the documented 415 V design relays. Confirm the fitted relay type, permissible operating range and actual site voltage before making adjustments.
3. Danfoss Controller Access
The Danfoss controller is located within the rooftop unit and is used for commissioning, viewing system operation, changing parameters and identifying alarms.
| Single Skin Access Level | Password |
|---|---|
| Level 1 | 1000 |
| Level 2 | 3000 |
| Level 3 | 5653 |
Installer passwords are technical-service information and should only be available to authorised personnel. The supplied guide lists different Level 3 passwords for double skin units; those are outside the scope of this article.
Starting the Unit
MENU → START → TURN ON
Ensure the system has a valid run command, no active emergency stop, correct operating conditions and no unresolved safety faults.
Changing Heating and Cooling Mode
The commissioning guide identifies a shortcut: hold the DOWN ARROW until the operating-mode icon changes. Alternatively, use the controller's Start / Heat-Cool menu where available.
Changing Temperature Setpoints
PARAMETERS → REGULATION → SET POINT
- sC1: Cooling setpoint.
- sH1: Heating setpoint.
Select the required parameter, press ENTER, adjust using the arrows and press ENTER to confirm.
4. Reading Controller Inputs and Outputs
MAIN MENU → UNIT STATUS → INPUT / OUTPUT
This section allows technicians to inspect system input and output values and determine the operating conditions being recognised by the controller.
Typical values include:
- Discharge pressure and other refrigerant circuit readings.
- Supply-air temperature.
- Return-air temperature.
- Outside-air temperature.
- Supply-fan and condenser-fan outputs.
- External damper control output, where installed.
Use the model-specific input/output tables in Commissioning Guide V1.4, pages 14–17, when identifying channel numbers. Do not assume double skin assignments are identical.
5. Cooling Regulation
The commissioning guide identifies cooling regulation proportional band rC1.
| Parameter | Value |
|---|---|
| Parameter | rC1 – Cooling regulation proportional band |
| Factory setting | 5 K |
| Guide recommendation | 2 K, where suitable for the application |
| Modbus ADU | 7086 |
Example from the guide: with a 20°C cooling setpoint and a 5 K proportional band, the compressor stops at 20°C and restarts at 25°C, subject to other control and protection logic.
6. Condenser Fan Regulation
Commissioning Guide V1.4 identifies the following cooling parameters:
| Parameter | Function | Modbus ADU |
|---|---|---|
| FCS | Condenser setpoint in cooling | 7152 |
| FCd | Condenser proportional band in cooling | 7153 |
The guide reports successful field operation with FCS = 28 bar and FCd = 6 bar in certain applications. These are field recommendations, not universal factory settings. Confirm suitability for the fitted fan-control equipment, refrigerant and site operating conditions before adjustment.
7. Modbus Communication
The documented default settings for the Danfoss Modbus RTU slave connection are:
| Modbus address | 10 |
| Baud rate | 19200 (bAU = 192) |
| Data format | 8N1 – 8 data bits, no parity, 1 stop bit |
After changing the unit's Modbus address, the commissioning guide instructs that the rooftop unit power be reset for the address change to take effect. Carry this out only through the appropriate shutdown and isolation procedure.
8. Alarms and Fault Diagnosis
Checking Active Alarms
MENU → ALARMS STATUS → ACTIVE ALARMS
Viewing Alarm History
MENU → ALARMS STATUS → ALARMS HISTORY
Resetting Alarms
MENU → ALARMS STATUS → RESET ALARMS
The guide also documents a long press of ESC for alarm reset.
Selected Alarm References
| Code | Description in Commissioning Guide |
|---|---|
| A01 | General alarm |
| A02 | Phase loss alarm |
| A04 | Condenser flow switch alarm |
| AE1 | Evaporator 1 antifreeze alarm |
| AE2 | Evaporator 2 antifreeze alarm |
| AH0 | General high pressure alarm |
| AH1 | Circuit 1 high pressure or compressor 1 protection alarm |
Note: The published commissioning alarm table includes generic controller functions that may not be fitted to every rooftop configuration. Always interpret alarms against the actual unit, current controller programming and applicable electrical diagram.
9. Troubleshooting Quick Checks
| Symptom | Initial Checks |
|---|---|
| Unit will not start | Remote enable, emergency stop, alarms, phase relay, controller mode, start delay and BMS command. |
| iOFF displayed | Check the external remote start / forced-stop circuit and control demand. |
| Phase fault | Supply voltage, phase availability, phase sequence and phase-monitoring relay. |
| High pressure alarm | Condenser airflow, fans, coil condition, refrigerant pressures and safety circuit. |
| Insufficient cooling | Setpoint, proportional band, supply airflow, filters, pressures, compressor stages and external demand. |
| Temperature reading incorrect | Sensor resistance, wiring, location, corresponding analogue input and calibration. |
| No BMS communication | RS485 polarity, termination, address, baud rate, parity, controller power and BMS mapping. |
10. Commissioning Records
Complete and retain the commissioning report. Record at minimum:
- Model, serial number, installation location and commissioning date.
- Electrical supply and individual phase readings.
- Compressor and fan currents.
- Return, supply and outdoor air temperatures.
- Refrigerant circuit readings and operating conditions.
- Safety protection tests, control inputs and BMS operation.
- Setpoints and altered parameters.
- Alarm history, outstanding issues and corrective actions.
Commissioning report template: Pages 32–36 of the same guide.
GENERAL AIRSTAGE | Service and commissioning reference for qualified technicians.