General Assist Technical Reference
Roof Top Packaged Unit Commissioning Guide
Danfoss controller setup, external inputs, economiser configuration, Modbus and commissioning checks
Applicable to Fujitsu General single-skin and double-skin RTPU systems
This guide consolidates the key settings and checks required when commissioning or servicing a Fujitsu General roof top packaged unit. Confirm the unit construction type before using terminal assignments, passwords or input/output tables, as single-skin and double-skin units differ.
Qualified technicians only: RTPU commissioning involves live three-phase electrical systems, rotating equipment, refrigerant pressures and control circuits. Isolate power before wiring or resistance checks and follow site safety procedures.
1. Commissioning quick reference
| Item | Recommended setting or action |
|---|---|
| Phase-fail relay - blue voltage dials | Rated 415 V. Set under-voltage and over-voltage to approximately 30 V where site conditions require adjustment. |
| Phase-fail relay - orange percentage dials | Rated 415 V. Recommended 12.5% over-voltage and 12.5% under-voltage. |
| Initial compressor oil heating | The controller can delay startup for 3 hours to heat compressor oil. Override only after confirming safe startup conditions. |
| Blackout time | Recommended 2 minutes. |
| Time off after restart | Recommended 2 or 3 minutes. Add a 1-minute offset between multiple RTPUs to avoid simultaneous startup. |
| Cooling proportional band rC1 | Factory 5 K; recommended 2 K, subject to application and design conditions. |
| Modbus | Default address 10, 19200 baud, 8N1. Power-cycle the RTPU after changing its Modbus address. |
2. anywAiR iO and SMT-770 wiring
| Equipment | Terminal | Connection |
|---|---|---|
| RTPU terminal X5 | 24V and 2 | 24 V AC for Smart Temp wall controller. 24V = active; 2 = neutral. |
| D1+ and D1- | RS485 / Modbus communication for SMT-770. | |
| 0V and 240V | 240 V supply for the 24 V DC transformer. | |
| SMT-770 | COMS A / COMS B | COMS A = RS485 positive; COMS B = RS485 negative. |
| POWER 24 / 24C | POWER 24 = 24 V AC active; POWER 24C = 24 V AC neutral. | |
| Rubix Compute | Power | 24 V DC power terminals. |
| 485-1 + / - / ground | Use for RS485. Do not use 485-2. | |
| ETH-1 | Use ETH-1 when an optional modem is fitted. |
3. External input terminals
Single-skin unit
- Pins 1 and 2: remote start when closed, or forced stop when open. When open, iOFF displays on the Danfoss controller.
- Pins 5 and 6: heat/cool selection. Heating when closed.
- Pins 7 and 8: emergency stop when open circuit.
Double-skin unit
- Pins 1 and 2: emergency stop when open circuit.
- Pins 3 and 4: remote start when closed, or forced stop when open.
- Pins 5 and 6: heat/cool selection. Heating when open; last command retained when closed.
Fire trip: On applicable units, fire trip or emergency stop may be connected to terminals 7 and 8. Activation may generate a supply fan or phase-loss alarm and a circuit 1 high-pressure or compressor-protection alarm.
4. Danfoss controller operation
Turn the unit on
MENU → START → TURN ON
Carter oil timer bypass
For an authorised forced start after verifying compressor oil-heating requirements:
LOGIN → password 5653 → START → FORCED TURN ON
Change operating mode
Hold the DOWN ARROW until the mode icon in the top-right corner changes between heating and cooling.
Adjust cooling or heating setpoint
PARAMETERS → REGULATION → SET POINT → sC1 or sH1 → ENTER → UP/DOWN → ENTER
sC1 is the cooling setpoint. sH1 is the heating setpoint.
Access levels
| Unit type | Level 1 | Level 2 | Level 3 |
|---|---|---|---|
| Single skin | 1000 | 3000 | 5653 |
| Double skin | 1000 | 3000 | 2299 or 6357 |
Read live inputs and outputs
MAIN MENU → UNIT STATUS → INPUT / OUTPUT
5. Input and output reference
Single-skin analogue inputs
| AI | Function | Minimum | Maximum |
|---|---|---|---|
| 1 | Discharge pressure - circuit 1 | 0.0 | 45.0 |
| 2 | Discharge pressure - circuit 2 | 0.0 | 45.0 |
| 3 | Supply-air temperature | -50.0 | 110.0 |
| 4 | Remote cooling/heating | 0 | 100 |
| 5-6 | Blank | 0.0 | 100.0 |
| 7 | Return-air temperature | -50.0 | 110.0 |
| 8 | Outdoor temperature | -50.0 | 110.0 |
Single-skin digital inputs
| DI | Function | Polarity |
|---|---|---|
| 1 | High-pressure switch - circuit 1 | N.C. |
| 2 | High-pressure switch - circuit 2 | N.C. |
| 3 | Low-pressure switch - circuit 1 | N.C. |
| 4 | Low-pressure switch - circuit 2 | N.C. |
| 5 | Condenser fan protection | N.C. |
| 6 | Supply filter | N.C. |
| 7 | Supply fan alarm | N.C. |
| 8 | Remote ON/OFF | N.C. |
Single-skin analogue outputs
| AO | Function | Signal |
|---|---|---|
| 1 | Condenser fan 1 | 0-10 V |
| 2 | Blank | |
| 3 | Supply fan | 0-10 V |
| 4 | External damper | 0-10 V |
Double-skin reference
The source commissioning guide identifies double-skin analogue input 16 as Supply temperature (?) and analogue output 1 as Source-side regulation valve (EEV?). Confirm these points against the specific unit wiring diagram and controller configuration before relying on them.
| Type | Point | Function |
|---|---|---|
| Analogue input | 1 | Return-air temperature |
| 2 | Outdoor temperature | |
| 3 | Suction pressure | |
| 5 | Discharge pressure | |
| 7 | Suction temperature | |
| 12 | Setpoint | |
| 16 | Supply temperature - verify on unit documentation | |
| Digital input | 1 | Remote ON/OFF |
| 3 | High-pressure switch - circuit 1 | |
| 7 | Compressor 1 protection - circuit 1 | |
| Analogue output | 1 | Source-side regulation valve - verify function |
| 3 | Supply fan |
6. Condenser fan and cooling control
Condenser fan settings
- Fan off below: 2800 kPa / 28 bar.
- FCS - condenser setpoint in cooling: Modbus ADU 7152.
- Fan at 100%: setpoint plus 800 kPa / 8 bar.
- FCd - condenser proportional band in cooling: Modbus ADU 7153.
- Units without fan-speed control switch the condenser fan on or off. Units with a speed controller modulate from 0% to 100%.
- The source guide reports stable operation at settings of 28 and 6 where a speed controller is fitted. Adjust to suit ambient and design conditions.
Cooling deadband / proportional band
| Parameter | rC1 - cooling regulation proportional band |
| Range | 0.1 to 20 K |
| Factory setting | 5 K |
| Recommended setting | 2 K, subject to application requirements |
| Modbus ADU | 7086 |
Example: With a 20°C setpoint and rC1 set to 5 K, the compressor stops at 20°C and restarts at 25°C.
7. Economiser and outside-air damper
Enable economiser temperature control
- Remove the fitted 10 kΩ resistor.
- Install an NTC 10 kΩ temperature sensor to measure outside air.
- On the outdoor controller, enter the level 3 password.
- Navigate to PARAMETERS → ROOFTOP → EXTERNAL DAMPER → CONFIGURATION.
- Change configuration from NO to TEMP.
Set minimum outside-air opening
MENU → LOGIN LEVEL 3 → PARAMETERS → ROOFTOP → EXTERNAL DAMPER → CONFIGURATION → MINIMUM OPENING
The fresh-air and return-air dampers operate together. For example, if the fresh-air damper is open 20%, the return-air damper should be open 80%.
Damper motor direction
| Damper | Specified rotation |
|---|---|
| Fresh-air servomotor | Clockwise |
| Return-air servomotor | Anti-clockwise |
If the dampers operate opposite to the intended sequence, check the direction setting on each servomotor and confirm the installation orientation.
8. Input calibration
To adjust an input offset, navigate to:
MAINTENANCE → CALIBRATION → SET CALIBRATION
| Input | Sensor |
|---|---|
| AI1 | High-pressure transducer - circuit 1 |
| AI2 | High-pressure transducer - circuit 2 |
| AI3 | Supply-air thermistor |
| AI7 | Return-air thermistor |
| AI8 | Outside-air thermistor |
9. Modbus communication
Commissioning practice: Disconnect the RTPU from the building management system while testing the machine and Danfoss settings. Reconnect the BMS after confirming correct standalone operation.
- Protocol: Modbus RTU slave over RS485.
- Default Modbus address: 10.
- Every node on the network must have a unique address.
- After changing the Modbus address, reset power to the RTPU for the change to take effect.
| Parameter | Value | Meaning |
|---|---|---|
| Cld | Site-specific | CAN serial node address |
| SEr | 10 default | Modbus serial node address |
| bAU | 192 default | 19200 baud |
| COM | 8N1 default | 8 data bits, no parity, 1 stop bit |
Available bAU values: 0 = disabled; 12 = 1200; 24 = 2400; 48 = 4800; 96 = 9600; 144 = 14400; 192 = 19200; 288 = 28800; 384 = 38400 baud.
Available COM values: 8N1, 8E1 or 8N2.
10. Alarm checks and reset
An alarm icon appears on the home screen when a fault is active. Some alarms may also activate an audible warning.
| Task | Menu path |
|---|---|
| Check active alarms | MENU → ALARMS STATUS → ACTIVE ALARMS |
| Check alarm history | MENU → ALARMS STATUS → ALARMS HISTORY |
| Reset alarms | MENU → ALARMS STATUS → RESET ALARMS, or press and hold ESC |
The source deck includes an “Error Codes” section heading but does not provide an error-code table. Record the displayed code and refer to the model-specific technical documentation or escalate through Technical Support.
11. Warranty periods
| Construction | Warranty stated in commissioning guide |
|---|---|
| Single skin | 2 years parts and labour, plus an additional 1 year parts-only warranty |
| Double skin | 1 year parts and labour |
Confirm current coverage: Warranty terms can depend on the equipment, sale date, application and contract. Verify the current warranty policy before making a commitment to a customer.
12. Commissioning and service checklist
Site and installation details
- Unit model and serial number
- Purpose of visit: commissioning or service
- Application: HVAC or process cooling
- Customer, installation name and address
- Technician name, date and activity timeline
Minimum service clearances
| Side | Required clearance | Measured on site |
|---|---|---|
| Electrical cabinet side A | 800 mm | ________ mm |
| Coil side B | 1800 mm | ________ mm |
| Back side C | 1800 mm | ________ mm |
| Coil side D | 1800 mm | ________ mm |
Pre-start checks
- Required clearances achieved and documentation supplied.
- Inspect the unit for transport or installation damage.
- Anti-vibration mounts installed where required.
- Crankcase heaters energised for the required period.
- Electrical screws, terminals and fasteners checked for tightness.
- Condenser fan rotation confirmed.
- Remote controls, airflow switch and supervisory devices confirmed.
- Refrigerant valves open and leak test completed.
Functional and safety checks
- Mechanical and software low-pressure protection.
- Mechanical and software high-pressure protection.
- Antifreeze alarm operation.
- Compressor startup and unloading sequence.
- Available airflow and thermal load adequate for testing.
- Gateway, BMS and other supervisor devices operate correctly.
Record operating data
- Three-phase supply voltages and unit current.
- Compressor voltages and current draw.
- Crankcase heater voltage and current.
- Supply and condenser fan voltage and current.
- Refrigerant type, number of circuits and charge per circuit.
- Air temperatures, airflow, condensing and evaporating pressures.
- Liquid and suction line temperatures, subcooling and superheat.
- Ambient temperature and site conditions during the test.
Source: Roof Top Packaged Unit Commissioning Guide, Version 1.4. Always confirm model-specific wiring diagrams, technical data and current service instructions before changing controller parameters.