Page 1 SERVICE MANUAL 3WAY VRF SYSTEM U-72MF1U9 U-72MF1U9E U-96MF1U9 U-96MF1U9E Model No. Outdoor Units Class U-72MF1U9 U-96MF1U9 Model Name U-72MF1U9E U-96MF1U9E Refrigerant R410A is used in the outdoor units. * Salt-Air Damage Resistant Specifications. Indoor Units Class 4-Way Cassette S-12MU1U6 S-18MU1U6...
Page 2: Please Read Before Starting
IMPORTANT! thin aluminum fins on the air conditioner can cut your fingers. Please Read Before Starting When Installing… This air conditioning system meets strict safety and operating standards. As the installer or service person, it Select an installation location which is rigid and strong is an important part of your job to install or service the enough to support or hold the unit, and select a location system so it operates safely and efficiently.
Page 3: Check Of Density Limit
When Servicing • Do not touch the air inlet or the CAUTION sharp aluminum fins of the • Turn the power OFF at the main power box (mains) outdoor unit. You may get injured. before opening the unit to check or repair electrical •...
Page 4: Precautions For Installation Using New Refrigerant
Precautions for Installation Using New Refrigerant 1. Care regarding tubing 1-1. Process tubing Material: Use C1220 phosphorous deoxidized copper specified in JIS H3300 “Copper and Copper Alloy Seamless Pipes and Tubes.” For tubes of ø7/8" (ø22.22 mm) or larger, use C1220 T-1/2H material or H material, and do not bend the tubes. Tubing size: Be sure to use the sizes indicated in the table below.
Page 5: New Refrigerant R410A Cannot Be Used For Earlier Models
3-2. Use R410A exclusive cylinder only. Valve Single-outlet valve (with siphon tube) Liquid refrigerant should be recharged with the cylinder standing on end as shown. Liquid New refrigerant R410A cannot be used for earlier models 1. Compressor specifications are different. If recharging a R22 or R407C compressor with R410A, durability will significantly decrease since some of the materials used for compressor parts are different.
Page 6: Table Of Contents
— CONTENTS — Section 1: CONTROL FUNCTIONS ......... . 1-1 Introduction .
Page 7 Section 4. REMOTE CONTROLLER FUNCTIONS ......4-1 Simple Settings Function ........... 4-2 Detailed Settings Function .
Page 9: Control Functions
3-WAY VRF SYSTEM Control Functions Contents 1. CONTROL FUNCTIONS 1. Introduction ............1-2 2.
Page 10: Introduction
3-WAY VRF SYSTEM Control Functions 1. Introduction The 3-WAY VRF is a system that allows multiple outdoor units to be connected. The outdoor units all contain inverter compressors, and the system does not utilize the sub units that were used in earlier systems. The outdoor unit where the unit No.
Page 11: Selecting Outdoor Unit For Operation
3-WAY VRF SYSTEM Control Functions 2. Selecting an Outdoor Unit for Operation 2-1. Outdoor Unit Operating Rules Because in this system all outdoor units contain an inverter compressor, ordinarily there is no absolute order of priority for compressor operation. Therefore there is no order of priority for the outdoor units. However, it is possible to operate the outdoor units in sequence, beginning with unit No.
Page 12: Compressor Control
3-WAY VRF SYSTEM Control Functions 3. Compressor Control 3-1. Compressors Mounted in the Outdoor Units [U-72MF1U9, U-72MF1U9E, U-96MF1U9, U-96MF1U9E] Capacity Compressor 1 Rotary DC Inverter DC Inverter Installed compressor Compressor 2 Scroll – 5 hp hp = horsepower Constant speed INV...
Page 13: Compressor Capacity Control
3-WAY VRF SYSTEM Control Functions 3. Compressor Control 3-3. Compressor Capacity Control The compressor operating conditions vary depending on the indoor unit operating conditions and on the effects of indoor heat load, outside temperature, and other factors. Unit No. 1 (CCU) calculates the required capacity according to these operating conditions, and allocates the capacity requirement among the outdoor units, according to the compressor start/stop rules.
Page 14 3-WAY VRF SYSTEM Control Functions 3. Compressor Control 3-6-1. Evaporation Temperature (Te) Control: Control of Indoor Units Operating in Cooling Mode 60.8 ˚F Horsepower increase 53.6 Area A permitted 51.9 51.8 51.8 Horsepower increase permitted Area AB 45.5 41.1 41.0 41.0 Horsepower increase Area B...
Page 15 3-WAY VRF SYSTEM Control Functions 3. Compressor Control 3-6-2. Condensation Temperature (Tc) Control: Control when there are indoor units operating in Heating mode PX = 125.6 ˚F Thermostat OFF Area D –0.1 Horsepower decrease Area C 118.5 118.4 118.4 Horsepower increase Area B prohibited 116.6...
Page 16 3-WAY VRF SYSTEM Control Functions 3. Compressor Control Compressor Control Table Condensation Temp. [Tc] High not_UP slow_UP Target STOP DOWN not_UP Evaporation temperature (Te) and condensation temperature (Tc) areas A, B, C, and D are the same as for evaporation temperature control and condensation temperature control. (2) Increasing/decreasing the heat exchanger capacity (when the outdoor unit heat exchanger is functioning as a condenser) •...
Page 17 3-WAY VRF SYSTEM Control Functions 3. Compressor Control (3) Increasing/decreasing the heat exchanger capacity (when the outdoor unit heat exchanger is functioning as an evaporator) • Primarily when both the evaporation temperature (Te) and condensation temperature (Tc) are low This occurs when the cooling capacity (heat intake) is high and the heating capacity (heat discharge) is low. The outdoor heat exchanger capacity is increased, increasing the system evaporation capacity and raising the evaporation temperature (Te).
Page 18: Special Controls
3-WAY VRF SYSTEM Control Functions 4. Special Controls (2) Current protection Inverter compressor current control is composed of primary current control and secondary current control. Current protection control for the inverter compressor is performed by self-protection in the inverter circuit, and does not increase or decrease the compressor capacity.
Page 19 3-WAY VRF SYSTEM Control Functions 4. Special Controls In addition to ordinary heating and cooling operation, this system also includes the following 3 types of special controls for control of the system as a whole. 1. Tube refrigerant recovery control 2.
Page 20: Defrost Control
3-WAY VRF SYSTEM Control Functions 4. Special Controls 4-2-3. Flow of system refrigerant oil recovery control (1) Simplified flow of system refrigerant oil recovery control System refrigerant oil recovery control follows this flow: Normal operation → 3-minute stop (May stop for 6 minutes.) → System refrigerant oil recovery control (Max. 3 minutes) →...
Page 21 3-WAY VRF SYSTEM Control Functions 4. Special Controls 4-3-3. Frost detection (A) Frost detection does not occur for 5 minutes after operation starts. (B) Frost is detected when either condition 1 or 2 below is met. Condition 1: L2 line or below is detected twice, each time continuously for 4 minutes, when the compressor is operating.
Page 22 3-WAY VRF SYSTEM Control Functions 4. Special Controls 4-3-6. Outdoor unit cycle defrost Outdoor unit cycle defrost is performed in systems where 2 outdoor units are connected to the refrigerant system. (1) Description of outdoor unit cycle defrost With this defrost method, when 1 outdoor unit operates in defrost mode (heat exchanger operating as a condenser), another outdoor unit operates as an evaporator in the same way as in ordinary heating mode.
Page 23 3-WAY VRF SYSTEM Control Functions 4. Special Controls 4-3-7. Defrost end judgment conditions Defrost ends when either of the below defrost end judgment conditions is met. Condition 1: The temperatures are 42.8°F or higher at all temperatures sensors installed on the outdoor unit heat exchangers.
Page 24: Other Controls
3-WAY VRF SYSTEM Control Functions 5. Other Controls 5-1. Oil Control 5-1-1. Oil level Oil level Meaning Oil state Assessment There is more than an adequate amount of oil in the This is the normal operating state Sufficient compressor. of the system and not a problem. Slightly The compressor may contain an adequate amount of oil, but Check that oil control recovers oil.
Page 25: Operation Of Solenoid Valves
3-WAY VRF SYSTEM Control Functions 6. Operation of Solenoid Valves 6-1. Refrigerant Control Valve [RCV] The main purpose of this valve is to detect the flow of refrigerant (refrigerant volume) on the indoor-unit side when the outdoor unit heat exchanger is functioning as a condenser. When the valve determines that there are signs of a low refrigerant level, refrigerant is supplied from the receiver tank to the system.
Page 26 3-WAY VRF SYSTEM Control Functions 6. Operation of Solenoid Valves 6-3. Balance Valve (BALV) This valve moves some of the oil from the oil separator to the balance tube. (1) When unit is stopped This valve is always OFF. (2) When unit is operating (A) This valve is ON when separator oil self-recovery control is in progress.
Page 27: Outdoor Unit Electronic Control Valves [Mov1, Mov2, Mov4]
3-WAY VRF SYSTEM Control Functions 7. Outdoor Unit Electronic Control Valves [MOV1, MOV2, MOV4] 7-1. Types of Electronic Control Valves [U-72MF1U9, U-72MF1U9E, U-96MF1U9, U-96MF1U9E] Capacity Electronic control valve 1 Heat exchanger 1 valve Heat exchanger 1 valve Electronic Electronic control valve 2...
Page 28 3-WAY VRF SYSTEM Control Functions 7. Outdoor Unit Electronic Control Valves [MOV1, MOV2, MOV4] 7-4. SC Circuit Electronic Control Valve [MOV4] (1) Operation to increase SC During cooling operation, or mixed heating/cooling operation when the outdoor unit heat exchanger is functioning as a condenser, the liquid refrigerant which condenses at the outdoor unit heat exchanger flows into the receiver tank, and SC (sub-cool = supercooling) approaches 0°F.
Page 29: Outdoor Fan Control
3-WAY VRF SYSTEM Control Functions 8. Outdoor Fan Control 8-1. Fan mode These outdoor units utilize a DC fan motor that can be controlled in a maximum of 16 steps (16 modes). However, fan modes 15 and 16 can only be used if high static-pressure mode has been set. * For information concerning EEPROM settings, refer to the field application functions.
Page 30: Demand Control
3-WAY VRF SYSTEM Control Functions 9. Demand Control Serial-parallel I/O must be connected in order to perform demand control. The below input is received by serial-parallel I/O, and demand control is performed. The demand values can be set as needed with this device. For more information, refer to the field application functions.
Page 31: Indoor Unit Control Of The Electronic Control Valve
3-WAY VRF SYSTEM Control Functions 10. Indoor Unit Control of the Electronic Control Valve 10-1. Normal Control (1) Cooling operation Position of electronic control valve Outdoor unit Outdoor unit operating stopped Stopped Thermostat Cooling Thermostat Performs SH control in the range of 55 – 480 –...
Page 32: Special Control
3-WAY VRF SYSTEM Control Functions 10. Indoor Unit Control of the Electronic Control Valve 10-2. Special Control Operating Control Subject indoor units Position of electronic control valve mode Fixed pulse for cooling, according to indoor unit Tube refrigerant oil Cooling All indoor units capacity recovery control...
Page 33: Solenoid Valve Kit Control
3-WAY VRF SYSTEM Control Functions 11. Solenoid Valve Kit Control This device connects the solenoid valve kit which is used to switch between indoor unit cooling/heating for 3-WAY types. Operation of the except type E1 solenoid valve kit Discharge Intake Balance EP valve (evaporation valve...
Page 34: Indoor Special Control
3-WAY VRF SYSTEM Control Functions 12. Indoor Special Control 12-1. Switching Control (EC control) If the settings indicate that an RAP valve kit is present (for type E1, the setting on initial shipment from the factory is “present”), then the thermostat does not turn ON for 3 minutes after the indoor unit operating mode is changed from any mode other than heating (including stopped) to heating with thermostat ON.
Page 35: Discharge Temperature
3-WAY VRF SYSTEM Control Functions 13. Discharge Temperature <Alarm Information> (1) Discharge temperature protection alarm This device sets an upper limit discharge temperature of 222°F for all compressors. When the discharge tem- perature reaches 222°F, that compressor is stopped and restarted. If the same high discharge condition occurs 4 times, then an alarm occurs.
Page 36: Current Protection
3-WAY VRF SYSTEM Control Functions 14. Current Protection (1) Fan motor Alarm Description Occurs when the fan motor detects overcurrent, or when the motor is locked and does not turn. (2) Inverter compressor Alarm Description Occurs during ordinary operation when overcurrent (27 A) is detected. Occurs under the same conditions as P16 when the inverter compressor is operating at or above 80 Hz.
Page 37: Low Oil Alarm
3-WAY VRF SYSTEM Control Functions 15. Low Oil Alarm Ordinary operation is resumed after system oil recovery control is completed. If a stop occurs again as a result of a low oil level, this alarm occurs. This alarm will not occur if system oil recovery control has not already been performed.
Page 38: Pressure Sensor Failure
3-WAY VRF SYSTEM Control Functions 16. Pressure Sensor Failure This system contains 2 types of pressure sensors: a high-pressure sensor and a low-pressure sensor. (1) High-pressure sensor failure Identification of a failure caused by a loose or displaced connector is based on the relationship between the pres- sure detected by the high-pressure sensor and the operation of the high-pressure switch, and on the relationship between the temperature detected by the high-pressure sensor and the various temperature thermistors.
Page 39: Backup Operation
3-WAY VRF SYSTEM Control Functions 17. Backup Operation <Field Application Functions> 17-1. Automatic Backup Operation This system includes a function for automatic backup operation. An alarm is also displayed to inform the operator that a failure has occurred. (1) Alarms that result in automatic backup operation When compressor trouble or fan motor trouble makes emergency continued operation impossible, automatic backup operation mode is engaged.
Page 40: Manual Backup
3-WAY VRF SYSTEM Control Functions 17. Backup Operation 17-2. Manual Backup If an alarm that does not result in automatic backup occurs frequently, possible causes include failure (such as refrigerant leakage) of a functional part at an outdoor unit other than the unit where the alarm occurs. In this case, because the outdoor unit service valve must be closed, backup operation must be performed manually.
Page 41: Service Maintenance Functions
3-WAY VRF SYSTEM Control Functions 18. Service Maintenance Functions The outdoor unit EEPROM settings can be used for the following functions. 18-1. Outdoor Unit Noise Countermeasure: EEPROM 05 (set at each outdoor unit) This unit includes 3 types of Quiet modes. (However, when they are engaged, operation is in Quiet mode 24 hours a day.) Selecting a Quiet mode results in operation that gives priority to reducing noise.
Page 42 3-WAY VRF SYSTEM Control Functions 18. Service Maintenance Functions 18-5. Automatic Backup Mode: Outdoor EEPROM 49 (set only on outdoor unit No. 1) Two types of automatic backup modes (when multiple outdoor units are installed) can be selected. Setting Operation Condition Backup outdoor units operate only during special control.
Page 43 3-WAY VRF SYSTEM Control Functions 18. Service Maintenance Functions 18-9. Compressor operating sequence: Outdoor EEPROM 46 (set at outdoor units which include CCU functions) When this setting is set to “1,” the compressors start in sequence beginning from the No. 1 outdoor unit. (The setting is “0”...
Page 44: Other Functions
3-WAY VRF SYSTEM Control Functions 19. Other Functions 19-1. Snowfall Sensor Functions: Outdoor EEPROM 04 A unit identified as having a snowfall sensor attached will periodically send a signal indicating the snowfall sensor input status to all outdoor units in the same system (or all wired outdoor units in the case of linked systems). It is therefore unnecessary to install and wire multiple snowfall sensors.
Page 45 3-WAY VRF SYSTEM Control Functions 19. Other Functions (3) Outdoor unit PCB LED indications in judgment mode LED1 LED2 Recommended response Judgment mode Blinking Blinking Normal Insufﬁ cient gas Blinking Charge with refrigerant a little at a time. Overcharge Blinking Recover refrigerant a little at a time.
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Page 47: Outdoor Unit Repair Procedures
3-WAY VRF SYSTEM Outdoor Unit Repair Procedures Contents 2. OUTDOOR UNIT REPAIR PROCEDURES 1. Removing Panels ............2-2 2.
Page 48: Removing Panels
3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 1. Removing Panels Procedures: 1. Removing Panels 2. Removing Electrical Component Box and Duct 3. Discharging Compressor Oil 4. Backup Operation 5. Recovering Refrigerant 6. Checking for Leakage After Repair 7. Evacuating System 8.
Page 49: Removing Electrical Component Box And Duct
3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 2. Removing Electrical Component Box and Duct Be sure to turn off the power before removing the electrical component box. Then check that the power LED (D53) on the control PCB of the outdoor unit is not lit. (1) Remove the electrical component box cover (remove 6 screws).
Page 50 3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 2. Removing Electrical Component Box and Duct (7) Remove the lower duct. (2 screws, 1 tab) (Fig. 2-6) Lower duct Fig. 2-6 (8) Remove the upper duct. (3 screws) (Fig. 2-7) Upper duct Fig.
Page 51: Discharging Compressor Oil
3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 3. Discharging Compressor Oil Discharged oil can be used for checking the condition of the system. Based on the appearance and color of the discharged oil, a judgment can be made on whether the system is operating normally or not. 3-1.
Page 52: Backup Operation
3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 4. Backup Operation This system includes an emergency automatic backup function that allows the A/C to operate during the period after trouble occurs until repairs are made. However, during repair and at other times, use manual backup operation.
Page 53 3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 4. Backup Operation <If the failed unit is the No. 1 outdoor unit (main unit)> If the No. 1 unit (main unit) has failed, a different outdoor unit must be set as the No. 1 unit (main unit). •...
Page 54 3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 4. Backup Operation • After adjusting the amount of refrigerant, turn OFF the power at the failed outdoor unit, release the short-circuit at the vacuum application pin, and close the liquid tube valve at the failed outdoor unit. * Refrigerant recovery is not affected by the power status of the failed outdoor unit.
Page 55: Recovering Refrigerant
3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 5. Recovering Refrigerant The following equipment and tools are required: Jumper wire with clips, adjustable wrench, set of manifold gauge valves specially designed for refrigerant R410A only, vacuum pump, refrigerant recovery unit, pre-purged refrigerant cylinder for recovery, flathead screwdriver, and outdoor unit maintenance remote controller.
Page 56 3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 5. Recovering Refrigerant 5-2. Refrigerant Recovery Procedures (Indoor Unit) The flowchart below shows the refrigerant recovery procedures you must follow when replacing or repairing the indoor unit due to trouble in the refrigerant circuit. START 5-2-1.
Page 57 3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 5. Recovering Refrigerant 5-2-1. Cooling operation (for all units) (1) If the remote controller (CZ-RTC2) is used for maintenance of the outdoor unit ➀ Connect the outdoor unit maintenance remote controller to the RC connector (CN006) (3P) (BLU) on any one of the outdoor unit control PCBs.
Page 58 3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 5. Recovering Refrigerant (6) Recover the remaining refrigerant from the indoor unit using the refrigerant recovery unit. Ball valve (separately purchased) Service port NOTE Suction tube Outdoor To determine completion of refrigerant Discharge tube unit recovery, follow the instructions that side...
Page 59 3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 5. Recovering Refrigerant ➈ Using hoses with Schrader-type push-to-release valves, connect the manifold gauge valves to the suction line service port, the discharge line service port and the liquid line service port in the next outdoor unit to undergo pump down.
Page 60: Checking For Leakage After Repair
3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 6. Checking for Leakage After Repair 6-1. Pressure Check for Leakage of Outdoor Unit After completing repair of the outdoor unit, carry out the following leakage check. (1) Check that all service valves for suction tube, discharge tube, liquid tube, and balance tube in the repaired outdoor unit are fully closed.
Page 61: Evacuating System
3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 7. Evacuating System This procedure is carried out to ensure there is no remaining refrigerant or other gases (nitrogen, etc.) in the repaired outdoor unit and tubing. 7-1. Evacuating Repaired Outdoor Unit (1) Check that each service valve of the suction tube, discharge tube, liquid tube, and balance tube in the outdoor unit are fully closed.
Page 62: Charging Compressor Oil
3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 8. Charging Compressor Oil 8-1. If Refrigerant Has Already Been Charged to Outdoor Unit Be sure to use an exclusive oil-charging tank for charging compressor oil. Prior to charging, carry out vacuum drying inside the tank and take care that no air (in the form of bubbles) is permitted to enter the tank. The oil charging procedures are given below.
Page 63 3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 8. Charging Compressor Oil (2) Charging compressor oil into oil-charging tank Connect a piece of pipe to the lower valve and then insert the other end deeply into the bottom of the oil container.
Page 64 3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 8. Charging Compressor Oil Next follow the instructions in “5-2-1. Cooling operation (for all units)” at the outdoor unit where oil will be charged, and start cooling operation at all units. When the operating conditions have stabilized, perform steps 1, 2, and 3 in sequence and open the valves.
Page 65 0.50 U-72MF1U9E (Inverter-controlled rotary compressor) C-9RVN273H0U 0.50 (Inverter-controlled rotary compressor) U-96MF1U9 U-96MF1U9E JT160G-KTTJ 0.55 (Constant-speed scroll compressor) When replacing a faulty compressor, be sure to first measure the amount of remaining oil in the compressor. Charge additional new oil equal to the difference in the remaining oil and the rated amount as listed above.
Page 66: Pumping Out Refrigerant From Outdoor Unit
3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 9. Pumping Out Refrigerant from Outdoor Unit 9-1. If Remote Controller (CZ-RTC2) is Used for Maintenance of Outdoor Unit (1) Refer to “4. Backup Operation” and perform backup operation. (2) Connect the manifold gauge valves at the Lo side to the low-pressure outlet port of the outdoor unit to be repaired.
Page 67 3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 9. Pumping Out Refrigerant from Outdoor Unit 9-2. If Remote Controller (CZ-RTC2) is Not Available for Maintenance of the Outdoor Unit (1) Refer to “4. Backup Operation” and perform backup operation. (2) Connect the manifold gauge valves at the Lo side to the low-pressure outlet port of the outdoor unit to be repaired.
Page 68 3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 9. Pumping Out Refrigerant from Outdoor Unit Faulty outdoor unit Other outdoor unit High-pressure outlet port Low-pressure outlet port Liquid tube service port (For 5/16" (7.94mm-dia. (For 5/16" (7.94mm-dia. (For 5/16" (7.94mm-dia. Manifold gauge connector) connector) connector)
Page 69: Compressor
3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 10. Compressor 10-1. Compressor Trouble Diagnosis and Check Methods Generally, compressor failures can be classified into the following categories. → (1) Mechanical trouble (A) Locking (intrusion of foreign objects, galling, etc.) (B) Pressure rise failure (damaged valve, seal, bearing, or other component) (C) Noise (damaged stator rotor, valve, or other component) →...
Page 70 3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 10. Compressor 10-2. Replacing the Compressor(s) 10-2-1. Replacing only the failed compressor If backup operation is required, follow the instructions in “4. Backup Operation” and engage backup operation. Follow the instructions in “10-3. Removing and Installing Compressors” and replace the failed compressor. Fully close the high- and low-pressure gauge valves on the manifold gauge, then stop the vacuum pump.
Page 71 3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 10. Compressor 10-2-2. Replacing all compressors in a failed unit Follow the instructions in “3. Discharging Compressor Oil” and drain the oil from the oil separator in the failed unit. Measure the amount of drained oil. If backup operation is required, follow the instructions in “4.
Page 72 3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 10. Compressor 10-2-3. Replacing all compressors in a system Follow the instructions in “3. Discharging Compressor Oil” and drain the oil from the oil separators in all outdoor units. Measure the amount of drained oil. Follow the instructions in “10-3.
Page 73 3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 10. Compressor 10-2-4. Dry core cleaning If burning or other failures occur repeatedly at compressors within the same system, in many cases the cause is acid, sludge, carbon, or other substances that remain in the refrigeration cycle as the result of insufficient cleaning. If, when the oil is inspected, there is an outdoor unit where the oil color phase is 4.0 or higher, or where a sharp odor is present, carry out all steps below to perform dry core cleaning.
Page 74 3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 10. Compressor (15) At all outdoor units where dry cores were removed, pressurize with 522.1 psi of nitrogen from the liquid tube service port and check for leaks. (16) After evacuating all nitrogen gas from the tubing, apply vacuum to all outdoor units where dry cores were removed until the pressure is –14.7 psig (5 Torr) or less.
Page 75: Replacing Compressors
3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 10. Compressor 10-3. Removing and Installing Compressors When removing and installing compressors, use sufficient caution to ensure that moisture or other substances do not enter the refrigerant tubing system. 10-3-1. Replacing compressors * For all types 72 and 96, follow the replacement procedure below. (A) Replacing the inverter compressor (Compressor 1 on remote controller alarm display) ■...
Page 76 3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 10. Compressor ■ Installation Remove the rubber stopper and tube cap (brazed) from the new compressor. Install the crankcase heater onto the new compressor. Place the 2 pieces of cushioning rubber in the designated positions on the compressor. Place the 2 pieces of cushioning rubber onto the legs of the new compressor.
Page 77 3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 10. Compressor (B) Replacing the constant-speed compressor (Compressor 2 on remote controller alarm display) ■ Removal Connect the manifold gauge to the high- and low-pressure outlet ports at the outdoor unit where the compres- sor will be replaced.
Page 78 3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 10. Compressor ■ Installation Remove the 2 brazed tube caps (2 pieces) from the compressor. Remove hexagonal caps from the compressor. * When removing the hexagonal caps, hold the fixing nut at the main unit side so as not to loose it with a wrench or spanner.
Page 79 3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 10. Compressor Brazing locations (3) Bolt Washer: 1 Rubber washer: 1 (1 each at the 3 locations) Protect the oil equalizer tube connectors Cushioning rubber guide Front view Fig. 2-28 Set the remaining cushioning rubber beneath the new compressor leg at the locations shown in the figure 2-28. Remove the bolts which are temporarily fastening the 2 pieces of cushioning rubber, and anchor the 3 compressor legs using the bolts, washers, and rubber washers.
Page 80 3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 10. Compressor (C) Replacing multiple compressors ■ Removal Follow the instructions in “(A) Replacing the inverter compressor,” “(B) Replacing the constant-speed compressor,” and remove the compressors. * There is no predetermined sequence for removal; any compressor may be removed first. ■...
Page 81: High And Low Pressure Sensors
3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 11. High and Low Pressure Sensors The outdoor unit connection ports for the high and low pressure sensors employ Schrader-type push-to-release valves. Therefore it is not necessary to recover refrigerant when removing and installing them. 11-1.
Page 82: Replacing 4-Way Valve
3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 12. Replacing 4-way valve When replacing 4-way valve of type 72 (for type with the inverter compressor), be sure to protect check valves, which are located adjacent to the 4-way valve, while performing replacement work. Type 96 (for type with 1 or 2 compressor) is not located near to the check valves, therefore no protection is necessary.
Page 83 3-WAY VRF SYSTEM Outdoor Unit Repair Procedures 12. Replacing 4-way valve 12-2. When the replacement is not available from the right side of the unit Follow the instructions of “10. Compressor” and remove the constant-speed compressor. Connect the manifold gauge to the high and low-pressure outlet ports at the outdoor unit where the 4-way valve will be replaced.
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Page 85: Outdoor Unit Maintenance Remote Controller
3-WAY VRF SYSTEM Outdoor Unit Maintenance Remote Controller Contents 3. OUTDOOR UNIT MAINTENANCE REMOTE CONTROLLER 1. Overview ............. . 3-2 2.
Page 86: Overview
3-WAY VRF SYSTEM Outdoor Unit Maintenance Remote Controller 1. Overview [Service Checker Section] OUTDOOR UNIT MAINTENANCE REMOTE CONTROLLER (CZ-RTC2) for 3-WAY VRF ■ About the outdoor unit maintenance remote controller The outdoor unit utilizes nonvolatile memory (EEPROM) on its PCB. This allows EEPROM data to replace the setting switches that were present on previous PCBs.
Page 87: Functions
3-WAY VRF SYSTEM Outdoor Unit Maintenance Remote Controller 2. Functions ■ Functions on the ordinary display (1) Functions: Button operations can be used to perform the following functions. • Start/stop of all indoor units • Switching between cooling and heating •...
Page 88: Ordinary Display Controls And Functions
3-WAY VRF SYSTEM Outdoor Unit Maintenance Remote Controller 3. Ordinary Display Controls and Functions ■ Functions on the ordinary display • Connect the special service checker wiring to the outdoor unit PCB. The connection is shown in the figure below. Outdoor unit PCB RC (3P, BLU) PCB connector (3P, BLU)
Page 89 3-WAY VRF SYSTEM Outdoor Unit Maintenance Remote Controller 3. Ordinary Display Controls and Functions ● All units start/stop (Fig. 3-1) <Operation> (ON/OFF operation) button can be used to start and stop all the indoor units. • The LED turns ON when 1 or more indoor units is operating.
Page 90 3-WAY VRF SYSTEM Outdoor Unit Maintenance Remote Controller 3. Ordinary Display Controls and Functions ■ Display (functions) • Use the temperature setting buttons to change the item code. Item code Item Remarks ➀ Outdoor unit alarm ➁ Alarm code display No.
Page 91 3-WAY VRF SYSTEM Outdoor Unit Maintenance Remote Controller 3. Ordinary Display Controls and Functions (3) XX-YY R.C. ➀ ➁ ➂ Locations where , and are displayed Displays the outdoor unit sub-bus address which is as shown in Fig. 3-3. currently selected. XX = Outdoor system address on main bus line (1 –...
Page 92 3-WAY VRF SYSTEM Outdoor Unit Maintenance Remote Controller 3. Ordinary Display Controls and Functions ■ Concerning the 7-segment, 4-digit display remote controller timer display The connected unit Nos. are displayed as shown below, using the 7-segment 4-digit ( ) display and the colon.
Page 93: Monitoring Operations
3-WAY VRF SYSTEM Outdoor Unit Maintenance Remote Controller 4. Monitoring Operations Display the indoor unit and outdoor unit sensor temperatures. <Operating procedure> ➀ Press and hold the (CHECK) button and buttons simultaneously for 4 seconds or longer to switch to temperature monitor mode. During temperature monitoring, is lit.
Page 94 3-WAY VRF SYSTEM Outdoor Unit Maintenance Remote Controller 4. Monitoring Operations ■ Display of unit No. 1 (main unit) Description Remarks Intake temp. °F °F °F °F Indoor unit Discharge temp. °F Discharge temp. setting °F Indoor unit electronic control valve position STEP Discharge temp.
Page 95: Outdoor Unit Alarm History Monitor
3-WAY VRF SYSTEM Outdoor Unit Maintenance Remote Controller 5. Outdoor Unit Alarm History Monitor • Displays outdoor unit alarms only. Does not display indoor unit alarms. • Check the indoor unit alarm histories separately using the indoor unit remote controllers or other control device. <Operating procedure>...
Page 96: Mode Settings
3-WAY VRF SYSTEM Outdoor Unit Maintenance Remote Controller 6. Mode Settings ■ Setting mode 1 Display of first 4 digits <Operating procedure> ➀ Press and hold the (CHECK) button and (VENTILATION) button simultaneously for 4 seconds or longer. ➁ Use the temperature setting buttons to change the item code.
Page 97 3-WAY VRF SYSTEM Outdoor Unit Maintenance Remote Controller 6. Mode Settings ■ Setting mode 2 <Operating procedure> ➀ Press and hold the (CHECK) button, button, and button simultaneously for 4 seconds or longer. ➁ Use the temperature setting buttons to change the item code.
Page 98 – MEMO – 3 - 14...
Page 99: Remote Controller Functions
3-WAY VRF SYSTEM Remote Controller Functions Contents 4. REMOTE CONTROLLER FUNCTIONS 1. Simple Settings Function ..........4-2 2.
Page 100: Simple Settings Function
3-WAY VRF SYSTEM Remote Controller Functions 1. Simple Settings Function • This allows the filter lifetime, operating mode [Remote Controller Functions Section] priority change, central control address, and other settings to be made for an individual or group- control indoor unit to which the remote controller used for simple settings is connected.
Page 101: List Of Simple Setting Items
3-WAY VRF SYSTEM Remote Controller Functions 1. Simple Settings Function List of Simple Setting Items Setting data Item code Item Description 0000 Not displayed 0001 150 hours 0002 2,500 hours Filter sign ON time (ﬁ tlter life time) 0003 5,000 hours 0004 10,000 hours 0005...
Page 102: Detailed Settings Function
3-WAY VRF SYSTEM Remote Controller Functions 2. Detailed Settings Function • This allows the system address, indoor unit address, and other settings to be made for the individual or group-control indoor unit to which the remote controller used for detailed settings is connected.
Page 103: List Of Detailed Setting Items
3-WAY VRF SYSTEM Remote Controller Functions 2. Detailed Settings Function List of Detailed Setting Items Setting data Item code Item Description Description Description Low Silhouette Ducted (F1), 4-Way Cassette (U1), 0000 0001 0005 1-Way Cassette (D1) 4-Way Cassette 60×60 (Y1) Slim Low Static Ducted (M1) High Static Pressure 0006...
Page 104 3-WAY VRF SYSTEM Remote Controller Functions 2. Detailed Settings Function Setting data Item code Item Description 0000 5 minutes (1B) Forced thermostat ON time 0001 4 minutes –010 –20°F –009 –18°F Cooling discharge –008 –16°F temperature shift 0010 +20°F –010 –20°F –009 –18°F...
Page 105 3-WAY VRF SYSTEM Remote Controller Functions 2. Detailed Settings Function Setting data Item code Item Description 0000 No forced operation 0001 Forced operation for 1 minute Automatic drain pump operation 0060 Continuous operation 0000 None Ventilation fan operation 0001 Ventilation fan operated by remote controller. 0000 Not used.
Page 106 3-WAY VRF SYSTEM Remote Controller Functions 2. Detailed Settings Function Setting data Item code Item Description DC fan tap operating Purpose mode 0000 Standard Standard (setting at shipment) High ceiling use High ceiling setting 1 (with standard panel) 0001 For low Ultra long-life ﬁ...
Page 107 3-WAY VRF SYSTEM Remote Controller Functions 2. Detailed Settings Function Simple setting items Item code Item Description Filter sign ON time setting Changes the indoor unit ﬁ lter lifetime when a high-performance ﬁ lter or other (ﬁ lter lifetime) optional product is installed. Reduces the ﬁ...
Page 108 3-WAY VRF SYSTEM Remote Controller Functions 2. Detailed Settings Function Item code Item Description Set when using a central control device. Central control address Used when setting the central control address manually from the remote controller. Operating mode priority change Note (1) NOTE (1) Explanation of operation mode priority change...
Page 109 3-WAY VRF SYSTEM Remote Controller Functions 2. Detailed Settings Function When the operating mode at the priority remote controller is changed, the operating modes of other remote controllers change as shown below. Mode change at priority remote controller Operating modes at other remote controllers Current mode New mode Current mode...
Page 110 3-WAY VRF SYSTEM Remote Controller Functions 2. Detailed Settings Function Item code Item Description Unit type Set when the indoor unit EEPROM memory is replaced during servicing. Indoor unit capacity System (outdoor unit) address These are not set at the time of shipping from the factory. These must be set after installation if automatic address setting is not Indoor unit address performed.
Page 111 3-WAY VRF SYSTEM Remote Controller Functions 2. Detailed Settings Function Item code Item Description 1F (Upper limit) Cooling 20 (Lower limit) 21 (Upper limit) This setting changes the temperature range (upper limit and lower limit) Heating 22 (Lower limit) Change to the remote which is set from the remote controller or central control device.
Page 112 3-WAY VRF SYSTEM Remote Controller Functions 2. Detailed Settings Function (Continued from previous page) Item code Item Description Heat exchanger temperature for The heat exchanger temperature control point for prevention of cold air cold air discharge discharge during heating operation can be changed. The indoor unit PCB optional output for the fan can be switched Fan output switching according to the purpose of use.
Page 113: Remote Controller Servicing Functions
3-WAY VRF SYSTEM Remote Controller Functions 3. Remote Controller Servicing Functions • The remote controller includes a number of servicing functions. Use these as needed for test runs and inspections. List of Servicing Functions Functions Description Button operation Reset operation Unit status Operation with Press and hold the...
Page 114: Test Run Function
3-WAY VRF SYSTEM Remote Controller Functions 3. Remote Controller Servicing Functions Test Run Function Operates the unit with the thermostat forced ON. <Procedure> ➀ Press and hold the button for 4 seconds or longer. ➁ “Test” appears on the remote controller LCD display (Fig.
Page 115 3-WAY VRF SYSTEM Remote Controller Functions 3. Remote Controller Servicing Functions ■ Sensor Temperature Display Function (displayed regardless of whether unit is operating or stopped) The procedure below displays the sensor temperatures from the remote controller, indoor unit, and outdoor unit on the remote controller. <Procedure>...
Page 116 3-WAY VRF SYSTEM Remote Controller Functions 3. Remote Controller Servicing Functions Outdoor unit sensors Indoor unit sensors Unit No.1 Unit No.2 Intake temp. Discharge temp. 1 Discharge temp. 2 High-pressure sensor temp. Heat exchanger gas 1 Heat exchanger liquid 1 Heat exchanger gas 2 Discharge temp.
Page 117: Trouble Diagnosis
3-WAY VRF SYSTEM Trouble Diagnosis Contents 5. TROUBLE DIAGNOSIS 1. Contents of Remote Controller Switch Alarm Display ......5-2 2.
Page 118: Contents Of Remote Controller Switch Alarm Display
3-WAY VRF SYSTEM Trouble Diagnosis 1. Contents of Remote Controller Switch Alarm Display Blinking: OFF: Wired Wireless remote remote controller control receiver display display Possible cause of malfunction Serial Remote controller is detecting Error in receiving serial communication signal. (Signal from communication error signal from indoor unit.
Page 119 3-WAY VRF SYSTEM Trouble Diagnosis 1. Contents of Remote Controller Switch Alarm Display Blinking: OFF: Wired Wireless remote remote controller control receiver display display Possible cause of malfunction Thermistor fault Outdoor unit Compressor 1 (INV) discharge temp. sensor Compressor 2 (constant speed) discharge temp. sensor Outdoor air temp.
Page 120: Outdoor Unit Control Panel Led Display
3-WAY VRF SYSTEM Trouble Diagnosis 2. Outdoor Unit Control Panel LED Display : ON : Blinking : OFF) LED (RED) Display meaning After the power is turned ON (and automatic address setting is not in progress), no communication with the indoor units in that system is possible. (Both ON) After power is turned ON (and automatic address setting is not in progress), 1 or more indoor units are conﬁ...
Page 121: Remote Controller Servicing Functions
3-WAY VRF SYSTEM Trouble Diagnosis 3. Remote Controller Servicing Functions Sensor temperature display function (displayed both when unit is running and stopped) • Use the following check procedure to display the sensor temperatures from the remote controller, indoor unit, and outdoor unit sensors on the remote controller display.
Page 122 3-WAY VRF SYSTEM Trouble Diagnosis 3. Remote Controller Servicing Functions Sensor Temperature Relationship Table Location where sensor Sensor Sensor Sensor type Sensor type is installed address address Remote controller temperature Discharge temperature sensor Indoor unit intake temperature Indoor unit heat exchanger Indoor unit electronic expansion Indoor unit temperature (E1)
Page 123: Way Vrf Alarm Codes
3-WAY VRF SYSTEM Trouble Diagnosis 4. 3-WAY VRF Alarm Codes With type 72, the INV compressor is compressor 1. With type 96, the INV compressor is compressor 1, and the constant-speed compressor is compressors 2. Alarm code Alarm meaning Page Outdoor unit failed to receive serial communication signals from indoor unit.
Page 124: Way Vrf Alarm Codes
3-WAY VRF SYSTEM Trouble Diagnosis 4. 3-WAY VRF Alarm Codes Compressor 1 discharge temperature trouble 5-23 High-pressure switch activated 5-24 Reverse phase (or missing phase) detected 5-24 Compressor 1 (INV) overcurrent 5-25 Compressor 2 discharge temperature trouble 5-23 Fan motor trouble 5-25 Inverter compressor high-frequency overcurrent alarm 5-26...
Page 125 3-WAY VRF SYSTEM Trouble Diagnosis 4. 3-WAY VRF Alarm Codes E06 Alarm Alarm code Alarm meaning Outdoor unit failed to receive serial communication signals from indoor unit. Alarm conditions Outdoor unit failed to receive serial communication signals from indoor unit. Probable cause (1) The indoor unit power was cut OFF after initial communications were completed.
Page 126 3-WAY VRF SYSTEM Trouble Diagnosis 4. 3-WAY VRF Alarm Codes E16 Alarm Alarm code Alarm meaning Automatic address setting alarm (too many units) Alarm conditions • The number of indoor units was too many when automatic address setting was performed. •...
Page 127 3-WAY VRF SYSTEM Trouble Diagnosis 4. 3-WAY VRF Alarm Codes E25 Alarm Alarm code Alarm meaning Outdoor unit address setting failure (duplication) Alarm conditions Communication by outdoor unit main-sub control wiring was received that contained the same address as that unit 5 times or more within 3 minutes. Probable cause The unit number is set incorrectly.
Page 128 3-WAY VRF SYSTEM Trouble Diagnosis 4. 3-WAY VRF Alarm Codes F04, F05 Alarm Alarm code F04, F05 Alarm meaning Compressor 1 discharge temperature sensor trouble, compressor 2 discharge temperature sensor trouble Alarm conditions (1) Discharge temp. of 212°F or higher was detected 20 minutes or more after that compressor stopped operating.
Page 129 3-WAY VRF SYSTEM Trouble Diagnosis 4. 3-WAY VRF Alarm Codes Check (3) Leakage from the discharge tube check valve Trouble: Although the other compressor is operating and this compressor is stopped, the discharge temperature of this compressor rises together with the temperature of the other compressor.
Page 130 3-WAY VRF SYSTEM Trouble Diagnosis 4. 3-WAY VRF Alarm Codes F08 Alarm Alarm code Alarm meaning Outdoor air temperature sensor trouble Alarm conditions (1) A/D step is 10 steps or less (short circuit). (2) A/D step is 1014 steps or more (open circuit) Probable cause (1) Sensor malfunction (including connector) (2) PCB malfunction...
Page 131 3-WAY VRF SYSTEM Trouble Diagnosis 4. 3-WAY VRF Alarm Codes F16 Alarm Alarm code Alarm meaning High-pressure sensor trouble (abnormal rise in high pressure) (In some cases this may not be the result of a high-pressure sensor malfunction.) Alarm conditions •...
Page 132 3-WAY VRF SYSTEM Trouble Diagnosis 4. 3-WAY VRF Alarm Codes Correction (1) Replace the high-pressure sensor. Caution: Because the high-pressure sensor connection employs a Schrader-type valve, it can be removed and replaced. However, the high-pressure sensor can be easily damaged by high voltage; therefore use sufﬁ cient caution with regard to static electricity.
Page 133 3-WAY VRF SYSTEM Trouble Diagnosis 4. 3-WAY VRF Alarm Codes H11, H12 Alarm Alarm code H11, H12 Alarm meaning H11: Constant speed compressor 2 overcurrent alarm H12: Constant speed compressor 2 lock current alarm Alarm conditions H11: During operation, the compressor current value exceeded 20 A for 30 seconds or longer. However this alarm is not detected for 4 seconds after the compressor starts.
Page 134 3-WAY VRF SYSTEM Trouble Diagnosis 4. 3-WAY VRF Alarm Codes H03, H13 Alarm Alarm code H03, H13 Alarm meaning H03: Compressor 1 CT sensor disconnected or short-circuit H13: Compressor 2 CT sensor disconnected or short-circuit Alarm conditions Compressor 1: Current value of more than 18.0 A is detected while the compressor 1 is stopped. Compressor 2: Current value at compressor 2 is less than 2.0 A when 2 seconds or more had passed after the compressors began operation and output.
Page 135 3-WAY VRF SYSTEM Trouble Diagnosis 4. 3-WAY VRF Alarm Codes H06 Alarm Alarm code Alarm meaning Abnormal low-pressure drop Alarm conditions A pre-trip occurs during the unit's operation when the low-pressure sensor installed at constant low-pressure parts detects a pressure of 7.25 psi or less continuously for 2 minutes, or an instantaneous pressure of 2.90 psi or less.
Page 136 3-WAY VRF SYSTEM Trouble Diagnosis 4. 3-WAY VRF Alarm Codes H07 Alarm Alarm code Alarm meaning No-oil alarm Alarm conditions This alarm occurs when oil does not ﬂ ow for a speciﬁ ed amount of time in tubing where oil ﬂ...
Page 137 3-WAY VRF SYSTEM Trouble Diagnosis 4. 3-WAY VRF Alarm Codes H08, H27 Alarm Alarm code H08, H27 Alarm meaning H08: Trouble (open circuit) with the oil sensor (connection) at compressor 1 H27: Trouble (open circuit) with the oil sensor (connection) at compressor 2 Alarm conditions This alarm occurs when a connector connection (pins 1 and 2 for compressor 1, pins 4 and 5 for compressor 2 is open.
Page 138 3-WAY VRF SYSTEM Trouble Diagnosis 4. 3-WAY VRF Alarm Codes L04 Alarm Alarm code Alarm meaning Outdoor system address duplication Alarm conditions Communication by inter-unit control wiring was received that contained the same address as that unit 5 times or more within 3 minutes. Probable cause Incorrect outdoor system address settings Check...
Page 139 3-WAY VRF SYSTEM Trouble Diagnosis 4. 3-WAY VRF Alarm Codes P03, P17 Alarm Alarm code P03, P17 Alarm meaning Compressor 1 discharge temperature trouble; Compressor 2 discharge temperature trouble Alarm conditions Inverter compressor 1: Temperature is 222°F or higher and pre-trip stop has occurred. Compressors 2 (constant speed): Pre-trip stop occurs at 222°F or above.
Page 140 3-WAY VRF SYSTEM Trouble Diagnosis 4. 3-WAY VRF Alarm Codes Correction (1) Replace the sensor. (2) Replace the outdoor unit PCB. (3) Correct the problem locations. Example All of the probable causes Notes Operates continuously for a set length of time. Indicates 2.5 minutes or longer for an inverter unit and 30 seconds or longer for a constant- speed compressor.
Page 141 3-WAY VRF SYSTEM Trouble Diagnosis 4. 3-WAY VRF Alarm Codes P16 Alarm Alarm code Alarm meaning Compressor 1 (INV) overcurrent alarm Alarm conditions This alarm occurs when current trouble or current detection trouble occur at an inverter frequency of less than 80 Hz after start (when trouble judgment current is detected in the primary or secondary current, or when an instantaneous secondary current of 48 A or higher is detected.
Page 142 3-WAY VRF SYSTEM Trouble Diagnosis 4. 3-WAY VRF Alarm Codes P26 Alarm Alarm code Alarm meaning Inverter compressor high-frequency overcurrent alarm Alarm conditions This alarm occurs when current trouble or current detection trouble occurs at an inverter frequency of 80 Hz or higher after start (when trouble judgment current is detected in the primary or secondary current, or when an instantaneous secondary current of 48 A or higher is detected).
Page 143: Blinking Inspection Display On The Remote Controller
3-WAY VRF SYSTEM Trouble Diagnosis 5. Blinking Inspection Display on the Remote Controller Blinking inspection display (2) (compressor magnet SW seizing detection) Alarm code (Blinking inspection display) Alarm meaning Compressor magnet SW seizing detected Status: Although an outdoor unit exists where the outdoor unit fan is running, no compressors in the system are operating.
Page 144: Inspection Of Parts
3-WAY VRF SYSTEM Trouble Diagnosis 6. Inspection of Parts (1) High-pressure switch (63PH1, 63PH2) • 63PH1: Disconnect the CN042 connector (3P, WHT) from the outdoor unit control panel. Measure the resis- tance between socket pins 1 and 3. The resistance is OK if the result is 0 Ω. •...
Page 145: Test Pin
3-WAY VRF SYSTEM Trouble Diagnosis 7. Test Pin When the test pin on the outdoor unit control PCB is short-circuited, each part can be operated individually. • After turning OFF the main unit power, short circuit the test pin (CN022, WHT), then turn the power back ON. Output is performed in the sequence shown in the table below, for 0.5 seconds each.
Page 146: Thermister Characteristics Curve
3-WAY VRF SYSTEM Trouble Diagnosis 8. Thermister Characteristics Curve 8-1. Room temp.sensor Temperature sensor Temperature (˚C) 8-2. Indoor heat exch. coil sensor (E1, E3) Indoor Heat Exchanger temperature sensor [E1, E3] Temperature (˚C) Temperature (˚C) 5 - 30...
Page 147 3-WAY VRF SYSTEM Trouble Diagnosis 8. Thermister Characteristics Curve 8-3. Outdoor temp. sensor, Compressor suction gas temp. sensor Outdoor heat exch. coil sensor, Oil temp. sensor Outdoor temperature, Suction gas temperature sensor Heat exchanger temperature, Oil temperature sensor -20 -15 -10 -5 Temperature (°C) Temperature (°C) 8-4.
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