Brand: DAIKIN
Category: Air Conditioning
Document Type: Manual
Language: EN
Manual for VRV
Uploaded: Sept. 12, 2025, 4:15 a.m.
Manual Publish Date: 2011-09-01
Warranty Information
Refer to the user's manual for important safety instructions and warnings before use.
This manual is a Service Diagnosis Pocket Manual for DAIKIN VRV systems. It provides information on troubleshooting symptoms, error codes, and applicable models.
Key sections include:
- Symptom-based Troubleshooting: Lists common symptoms and their supposed causes and countermeasures.
- Troubleshooting by Indication on the Remote Controller: Details various error codes and their meanings, including thermistor and pressure sensor characteristics, and wiring checks.
- Applicable Models: Lists the series of VRV indoor and outdoor units.
The manual is intended for service personnel to diagnose and resolve issues with VRV air conditioning systems.
Troubleshooting and error codes
| Symptom | Supposed Cause | Countermeasure |
|---|---|---|
| 1 The system does not start operation at all. | Blowout of fuse(s) | Turn OFF the power supply and then replace the fuse(s). |
| Cutout of breaker(s) | • If the knob of any breaker is in its OFF position, turn ON the power supply. • If the knob of any circuit breaker is in its tripped position, do not turn ON the power supply. |
|
| Power failure | After the power failure is reset, restart the system. | |
| 2 The system starts operation but makes an immediate stop. | Blocked air inlet or outlet of indoor or outdoor unit | Remove obstacle(s). |
| Clogged air filter(s) | Clean the air filter(s). | |
| 3 The system does not cool or heat air well. | Blocked air inlet or outlet of indoor or outdoor unit | Remove obstacle(s). |
| Clogged air filter(s) | Clean the air filter(s). | |
| Enclosed outdoor unit(s) | Remove the enclosure. | |
| Improper set temperature | Set the temperature to a proper degree. | |
| Airflow rate set to "LOW" | Set it to a proper airflow rate. | |
| Improper direction of air diffusion | Set it to a proper direction. | |
| Open window(s) or door(s) | Shut it tightly. | |
| [In cooling] Direct sunlight received | Hang curtains or shades on windows. | |
| [In cooling] Too many persons staying in a room | The model must be selected to match the air conditioning load. | |
| [In cooling] Too many heat sources (e.g. OA equipment) located in a room | The model must be selected to match the air conditioning load. | |
| 4 The system does not operate. | The system stops and immediately restarts operation. | Normal operation. The system will automatically start operation after a lapse of 5 minutes. |
| Pressing the TEMP ADJUST button immediately resets the system. | The system is controlled with centralized controller. Blinking display indicates that the system cannot be operated using the remote controller. | |
| The remote controller displays "UNDER CENTRALIZED CONTROL", which blinks for a period of several seconds when the OPERATION button is depressed. | The system is in preparation mode of micro computer operation. | |
| 5 The system makes intermittent stops. | The remote controller displays error codes "U4" and "U5", and the system stops but restarts after a lapse of several minutes. | The system stops due to an interruption in communication between units caused by electrical noises coming from equipment other than air conditioners. |
| Remove causes of electrical noises. If these causes are removed, the system will automatically restart operation. |
||
| 6 COOL-HEAT selection is disabled. | The remote controller displays "UNDER CENTRALIZED CONTROL". | This remote controller has no option to select cooling operation. |
| The remote controller displays "UNDER CENTRALIZED CONTROL", and the COOL-HEAT selection remote controller is provided. | COOL-HEAT selection is made using the COOL-HEAT selection remote controller. | |
| Use the COOL-HEAT selection remote controller to select cool or heat. | ||
| 7 The system conducts fan operation but not cooling or heating operation. | This symptom occurs immediately after turning ON the power supply. | The system is in preparation mode of operation. |
| Wait for a period of approximately 10 minutes. | ||
| 8 The airflow rate is not reproduced according to the setting. | Even pressing the AIRFLOW RATE SET button makes no changes in the airflow rate. | In heating operation, when the room temperature reaches the set degree, the outdoor unit will stop while the indoor unit is brought to fan LL operation so that no one gets cold air. Furthermore, if fan operation mode is selected when other indoor unit is in heating operation, the system will be brought to fan LL operation. (The fan LL operation is also enabled while in oil return mode in cooling operation.) |
| Normal operation. | ||
| 9 The airflow direction is not reproduced according to the setting. | The airflow direction is not corresponding to that displayed on the remote controller. The flap does not swing. | Automatic control |
| Normal operation. | ||
| 10 A white mist comes out from the system. | <Indoor unit> In cooling operation, the ambient humidity is high. (This indoor unit is installed in a place with much oil or dust.) | Uneven temperature distribution due to heavy stain of the inside of the indoor unit |
| Clean the inside of the indoor unit. | ||
| <Indoor unit> Immediately after cooling operation stopping, the ambient temperature and humidity are low. | Hot gas (refrigerant) flown in the indoor unit results to be vapor from the unit. | |
| Normal operation. | ||
| <Indoor and outdoor units> After the completion of defrosting operation, the system is switched to heating operation. | Defrosted moisture turns to be vapor and comes out from the units. | |
| Normal operation. | ||
| 11 The system produces sounds. | <Indoor unit> Immediately after turning ON the power supply, indoor unit produces "ringing" sounds. | These are operating sounds of the electronic expansion valve of the indoor unit. |
| Normal operation. This sound becomes low after a lapse of approximately 1 minute. |
||
| <Indoor and outdoor units> "Hissing" sounds are continuously produced while in cooling or defrosting operation. | These sounds are produced from gas (refrigerant) flowing respectively through the indoor and outdoor units. | |
| Normal operation. | ||
| <Indoor and outdoor units> "Hissing" sounds are produced immediately after the startup or stop of the system, or the startup or stop of defrosting operation. | These sounds are produced when the gas (refrigerant) stops flowing. | |
| Normal operation. | ||
| <Indoor unit> Faint sounds are continuously produced while in cooling operation or after stopping the operation. | These sounds are produced from the drain discharge device in operation. | |
| Normal operation. | ||
| <Indoor unit> "Creaking" sounds are produced while in heating operation or after stopping the operation. | These sounds are produced from resin parts expanding and contracting with temperature changes. | |
| Normal operation. | ||
| <Indoor unit> Sounds like "trickling" or the like are produced from indoor units in the stopped state. | On VRV systems, these sounds are produced when other indoor units in operation. The reason is that the system runs in order to prevent oil or refrigerant from dwelling. | |
| Normal operation. | ||
| <Outdoor unit> Pitch of operating sounds changes. | The reason is that the compressor changes the operating frequency. | |
| Normal operation. | ||
| 12 Dust comes out from the system. | Dust comes out from the system when it restarts after the stop for an extended period of time. | Dust, which has deposited on the inside of indoor unit, is blown out from the system. |
| The inside of the indoor unit should be cleaned. | ||
| 13 Odors come out from the system. | In operation | Odors of room, cigarettes or else adsorbed to the inside of indoor unit are blown out. |
| The inside of the indoor unit should be cleaned. | ||
| 14 Outdoor unit fan does not rotate. | In operation | The reason is that fan revolutions are controlled to put the operation to the optimum state. |
| Normal operation. | ||
| 15 LCD display "88" appears on the remote controller. | Immediately after turning ON the power supply | The reason is that the system is checking to be sure the remote controller is normal. |
| Normal operation. This code is displayed for a period of approximately 1 minute at maximum. |
||
| 16 The outdoor unit compressor or the outdoor unit fan does not stop. | After stopping operation | It stops in order to prevent oil or refrigerant from dwelling. |
| Normal operation. It stops after a lapse of approximately 5 to 10 minutes. |
||
| 17 The outdoor gets hot. | While stopping operation | The reason is that the compressor is warmed up to provide smooth startup of the system. |
| Normal operation. | ||
| 18 Hot air comes out from the system even though it stops. | Hot air is felt while the system stops. | On VRV systems, small quantity of refrigerant is fed to indoor units in the stopped state when other indoor units are in operation. |
| Normal operation. | ||
| 19 The system does not cool air well. | The system is in dry operation. | The reason is that the dry operation serves not to reduce the room temperature where possible. |
| Change the system to cooling operation. |