General Assist Technical Reference
VRF Check List - Powering Up
Pre-power checks, address verification and cooling test-run checks
For VRF commissioning and service personnel
Use this checklist before energising the VRF system and again after power is applied. It consolidates the source test-run checks for power supply, outdoor and indoor unit setup, addressing, cooling test-run operation and basic operating measurements.
Important: All electrical, refrigerant and commissioning work must be completed by suitably qualified personnel. Confirm power is isolated before checking wiring, terminals, DIP switches, valves or PCB connections.
1. Check items before Power ON
Power source
| Check item | Judgement standard | Check |
|---|---|---|
| Circuit breaker capacity | Outdoor unit: 50 A (AJ*144/126/108), 30 A (AJ*9072) Indoor unit: 20 A | ☐ |
| Power source wiring - circuit breaker | 30 A = 4 mm²; 50 A = 10 mm²; 60 A = 16 mm²; 80 A = 22 mm²; 100 A = 38 mm² | ☐ |
| Power source wiring - outdoor unit | 10 mm² (AJ*144/126/108), 4.0 mm² (AJ*9072) | ☐ |
| Power source wiring - indoor unit | 2.5 mm² | ☐ |
| Supply power source - outdoor unit | Using a phase tester, etc., check the phase of the power source. R-S: AC 400 V (380-415 V) S-T: AC 400 V (380-415 V) T-R: AC 400 V (380-415 V) | ☐ |
| Supply power source - indoor unit | AC 230 V (220-240 V) | ☐ |
Outdoor unit
| Check item | Judgement standard | Check |
|---|---|---|
| Appearance | No scratches or deformation. Be careful of deformation of the front panel. | ☐ |
| Serial No. | Check and enter in the check sheet. | ☐ |
| Outside air temperature | Check and enter in the check sheet. | ☐ |
| Power source wiring connection | Check connection points and loose terminal-panel screws. | ☐ |
| Communication line | 0.33 mm² shielded wire used (22AWG). Check connections and loose terminal-panel screws. | ☐ |
| Connection piping | Check whether heat-insulation material is installed without a gap. | ☐ |
| DIP-SW setting | Outdoor unit address setting (SET: 3-1, 2) Number of slave units (SET: 3-3, 4) Number of outdoor units installed (SET: 5-1, 2) Terminal resistor setting (SET: 5-4) | ☐ |
| Rotary SW setting | Refrigerant circuit address setting (SET: REF AD x10 & x1) | ☐ |
| Additional refrigerant amount | Compare calculated value and value written on the electric box. Enter in check sheet. | ☐ |
| 3-way valves | MASTER gas pipe: fully open MASTER liquid pipe: fully open SLAVE1 gas pipe: fully open SLAVE1 liquid pipe: fully open SLAVE2 gas pipe: fully open SLAVE2 liquid pipe: fully open | ☐ |
3-way valve warning: The source states that if the system is operated with a 3-way valve closed, oil discharged from the compressor will not be returned and trouble may result.
Indoor unit
| Check item | Judgement standard | Check |
|---|---|---|
| Appearance | No scratches, deformation, tilting, etc. | ☐ |
| Serial No. | Check and enter in the check sheet. | ☐ |
| Drain cap installation | Installed positively. | ☐ |
| Power source wiring | Check connections and loose terminal-panel screws. | ☐ |
| Communication line | 0.33 mm² shielded wire used (22AWG). Check connections and loose terminal-panel screws. | ☐ |
| Remote controller wiring | 0.33 mm². Check connections and loose terminal-panel screws. | ☐ |
| Connection piping | Check whether heat-insulation material is installed without a gap. | ☐ |
| Rotary SW setting | Refrigerant circuit address (REF AD) Indoor unit address (IU AD) At automatic address setting, IU AD / REF AD shall be [0] Remote controller address (RC AD) | ☐ |
| DIP-SW setting | Function setting - remote controller custom code / external input switching / auxiliary heater ON-OFF. | ☐ |
2. Check items after Power ON
Cooling test-run note: Complete a cooling test run for each refrigerant circuit. If multiple refrigerant circuits are test-run at the same time, refrigerant circuit address-setting errors cannot be detected.
| Check item | Judgement standard | Check |
|---|---|---|
| Outdoor unit circuit breaker ON | Check lighting of PC board LED101 and 7-segment display. | ☐ |
| Indoor unit circuit breaker ON | Check whether indoor-unit OPERATION and TIMER lamps flash alternately. | ☐ |
| Outdoor unit PC board push-button SW setting | Confirm all necessary functions are set. | ☐ |
| Automatic address setting | Addresses assigned to all indoor units. Check for unset or duplicated addresses. | ☐ |
| Address read | All indoor and outdoor units in the same refrigerant circuit can be checked on the service tool. | ☐ |
| Address record | Enter the set addresses in the check sheet. | ☐ |
| Address hold check | Check that no address setting is held by the service tool after indoor/outdoor circuit breakers are turned OFF then ON. | ☐ |
Indoor power: Turn on all indoor units in the same refrigerant circuit address. The source notes that operating the system with indoor units remaining without power can cause malfunction.
3. Cooling test run - after approximately 30 minutes
Operate the outdoor unit from the master push-button switch. All indoor units in the same refrigerant circuit should enter cooling test-run operation, and the outdoor units corresponding to the operating capacity of the indoor units should operate.
Service tool values - representative source figures
| Item | Representative value | Check |
|---|---|---|
| High pressure | HPS: 2.7 MPa | ☐ |
| Low pressure | LPS: 0.8 MPa | ☐ |
| Discharge pipe temperature - outdoor unit | TH1 (TH2): 87°C | ☐ |
| Suction pipe temperature - outdoor unit | TH4: 17°C | ☐ |
| Subcool | TH6 - TH7: 10°C or greater | ☐ |
| Indoor inlet air temperature | TH21: 27°C | ☐ |
| Indoor heat-exchanger inlet temperature | TH22: 11°C | ☐ |
| Indoor heat-exchanger outlet temperature | TH24: 13°C | ☐ |
| Compressor operation | Operate corresponding to the operating capacity of the indoor units. | ☐ |
| Data output | Using service tool, output CSV to Excel. | ☐ |
Representative values only: The source states that the starred figures are representative values for AJYA90LALH at standard conditions of indoor 27°C and outdoor 35°C. Values will vary with outdoor-unit capacity, indoor/outdoor temperature, indoor-unit capacity, pipe length and other conditions.
Outdoor-unit operational checks
| Check item | Judgement standard | Check |
|---|---|---|
| PC board / 7-segment display | The 7-segment display of all outdoor units in the same refrigerant circuit shall display. | ☐ |
| Operating voltage | R-S: AC 400 V (380-415 V) S-T: AC 400 V (380-415 V) T-R: AC 400 V (380-415 V) | ☐ |
| Abnormal sound / vibration | No abnormal sound or abnormal vibration. Outdoor fan shall not make a moaning sound. No discharge-air leakage from the outdoor duct. No pipe chattering sound or flute sound. | ☐ |
Indoor units - system-wide check
| Check item | Judgement standard | Check |
|---|---|---|
| Outlet air temperature | Inlet-air and outlet-air temperature difference shall be 10°C or greater. | ☐ |
| Abnormal sound / vibration | No abnormal sound or abnormal vibration. | ☐ |
| Water leakage | No water leakage and no condensation on the drain, cabinet, piping or discharge port. | ☐ |
| Remote controller operation | Operate according to settings - ON/OFF and set-temperature change. | ☐ |
4. Individual indoor-unit operation
| Check item | Judgement standard | Check |
|---|---|---|
| Fan operation | Fan shall be switched to all fan speeds in cooling mode. | ☐ |
| Louver operation - except duct | Louver shall switch to all positions and also swing. | ☐ |
| Outlet air temperature | Inlet-air and outlet-air temperature difference shall be 10°C or greater. | ☐ |
| Abnormal sound / vibration | No abnormal sound or abnormal vibration. | ☐ |
| Water leakage | No water leakage and no condensation on the drain, cabinet, piping or discharge port. | ☐ |
| Remote controller operation | Operate according to settings - ON/OFF and set-temperature change. | ☐ |
Commissioning completion: Record serial numbers, addresses, refrigerant charge information and test results on the applicable commissioning/check sheet before handover.