Panasonic 3-Way Service Manual

SERVICE MANUAL

U-72MF1U9 U-72MF1U9E U-96MF1U9 U-96MF1U9E**

3WAY VRF SYSTEM

Model No.

Outdoor Units

9672Class

Model Name

Refrigerant R410A is used in the outdoor units. * Salt-Air Damage Resistant Specifications.

U-72MF1U9 U-72MF1U9E

U-96MF1U9 U-96MF1U9E

Indoor Units

Class 9 12 15 18 2419 36 54487

4-Way Cassette

4-Way Cassette 60×60

1-Way Cassette

Low Silhouette Ducted

Slim Low Static Ducted

High Static Pressure

Ducted

Ceiling

Wall Mounted

Floor Standing

Concealed Floor

Standing

** Necessary to install the External Electronic Expansion Valve Kit (Optional:CZ-P56SVK1U).

85464849301000

S-07MD1U6

S-07MF1U6

S-07MM1U6

S-07MK1U6

S-07MP1U6

S-07MR1U6

S-09MD1U6

S-09MF1U6

S-09MM1U6

S-09MK1U6

S-09MP1U6

S-09MR1U6

S-12MU1U6

S-12MY1U6

S-12MD1U6

S-12MF1U6

S-12MM1U6

S-12MT1U6

S-12MK1U6

S-12MP1U6

S-12MR1U6

S-15MF1U6

S-15MM1U6

S-15MP1U6

S-15MR1U6

S-18MU1U6

S-18MY1U6

S-18MF1U6

S-18MM1U6

S-18MT1U6

S-18MK1U6

S-18MP1U6

S-18MR1U6

S-19MS1U6**

S-24MU1U6

S-24MF1U6

S-24MT1U6

S-24MK1U6

S-24MP1U6

S-24MR1U6

S-36MU1U6

S-36MF1U6

S-36ME1U6

REFERENCE NO.

S-48MF1U6

S-48ME1U6

S-54MF1U6

SM830201-00

IMPORTANT! Please Read Before Starting

This air conditioning system meets strict safety and operating standards. As the installer or service person, it is an important part of your job to install or service the system so it operates safely and efficiently.

For safe installation and trouble-free operation, you must:

Carefully read this instruction booklet before beginning. Follow each installation or repair step exactly as shown. Observe all local, state, and national electrical codes. Pay close attention to all warning and caution notices

given in this manual.

This symbol refers to a hazard or

WARNING

CAUTION

If Necessary, Get Help

These instructions are all you need for most installation sites and maintenance conditions. If you require help for a special problem, contact our sales/service outlet or your certified dealer for additional instructions.

In Case of Improper Installation

The manufacturer shall in no way be responsible for improper installation or maintenance service, including failure to follow the instructions in this document.

SPECIAL PRECAUTIONS

WARNING

Do not supply power to the unit until all wiring and tubing • are completed or reconnected and checked.

Highly dangerous electrical voltages are used in this • system. Carefully refer to the wiring diagram and these instructions when wiring. Improper connections and inadequate grounding can cause accidental injury or death.

•

Ground the unit following local electrical codes. Connect all wiring tightly. Loose wiring may cause •

overheating at connection points and a possible fire hazard.

To prevent possible hazards from insulation failure, • the unit must be grounded.

When Transporting

Be careful when picking up and moving the indoor and outdoor units. Get a partner to help, and bend your knees when lifting to reduce strain on your back. Sharp edges or

When Wiring

ELECTRICAL SHOCK CAN CAUSE SEVERE PERSONAL INJURY OR DEATH. ONLY A QUALIFIED, EXPERIENCED ELECTRICIAN SHOULD ATTEMPT TO WIRE THIS SYSTEM.

unsafe practice which can result in severe personal injury or death.

This symbol refers to a hazard or unsafe practice which can result in personal injury or product or property damage.

thin aluminum fins on the air conditioner can cut your fingers.

When Installing…

Select an installation location which is rigid and strong enough to support or hold the unit, and select a location for easy maintenance.

…In a Room

Properly insulate any tubing run inside a room to prevent “sweating” that can cause dripping and water damage to

walls and floors.

Keep the fire alarm and the air

CAUTION

…In Moist or Uneven Locations

Use a raised concrete pad or concrete blocks to provide a solid, level foundation for the outdoor unit. This prevents water damage and abnormal vibration.

…In an Area with High Winds

Securely anchor the outdoor unit down with bolts and a metal frame. Provide a suitable air baffle.

…In a Snowy Area (for Heat Pump-type Systems)

Install the outdoor unit on a raised platform that is higher than drifting snow. Provide snow vents.

outlet at least 5 feet away from the unit.

When Connecting Refrigerant Tubing

Ventilate the room well, in the event that is refrigerant • gas leaks during the installation. Be careful not to allow contact of the refrigerant gas with a flame as this will cause the generation of poisonous gas.

Keep all tubing runs as short as possible.• Use the flare method for connecting tubing.• Apply refrigerant lubricant to the matching surfaces of •

the flare and union tubes before connecting them, then tighten the nut with a torque wrench for a leak-free connection.

Check carefully for leaks before starting the test run.•

When performing piping work do • not mix air except for specified refrigerant (R410A) in refrigeration cycle. It causes capacity down, and risk of explosion and injury due to high tension inside the

WARNING

Do not leak refrigerant while piping work for an • installation or re-installation, and while repairing refrigeration parts. Handle liquid refrigerant carefully as it may cause

frostbite.

refrigerant cycle. Refrigerant gas leakage may • cause fire. Do not add or replace refrigerant •

other than specified type. It may cause product damage, burst and injury etc.

When Servicing

Turn the power OFF at the main power box (mains) • before opening the unit to check or repair electrical parts and wiring.

Keep your fingers and clothing away from any moving • parts.

Clean up the site after you finish, remembering to check • that no metal scraps or bits of wiring have been left inside the unit being serviced.

WAR NI NG

Do not clean inside the indoor and • outdoor units by users. Engage authorized dealer or specialist for cleaning.

In case of malfunction of this • appliance, do not repair by yourself. Contact to the sales dealer or service dealer for a repair.

Others

CAUTION

Do not touch the air inlet or the

• sharp aluminum fins of the outdoor unit. You may get injured. Ventilate any enclosed areas when • installing or testing the refrigeration system. Escaped refrigerant gas, on contact with fire or heat, can produce dangerously toxic gas.

Confirm after installation that no • refrigerant gas is leaking. If the gas comes in contact with a burning stove, gas water heater, electric room heater or other heat source, it can cause the generation of poisonous gas.

Do not touch the air inlet or the

• sharp aluminum fins of the outdoor unit. You may get injured. Do not sit or step on the unit, • you may fall down accidentally.

Do not stick any object into the • FAN CASE. You may be injured and the unit may be damaged.

Check of Density Limit

The room in which the air conditioner is to be installed requires a design that in the event of refrigerant gas leaking out, its density will not exceed a set limit.

The refrigerant (R410A), which is used in the air conditioner, is safe, without the toxicity or combustibility of ammonia, and is not restricted by laws imposed to protect the ozone layer. However, since it contains more than air, it poses the risk of suffocation if its density should rise excessively. Suffocation from leakage of refrigerant is almost non-existent. With the recent increase in the number of high density buildings, however, the installation of multi air conditioner systems is on the increase because of the need for effective use of floor space, individual control, energy conservation by curtailing heat and carrying power, etc. Most importantly, the multi air conditioner system is able to replenish a large amount of refrigerant compared to conventional individual air conditioners. If a single unit of the multi air conditioner system is to be installed in a small room, select a suitable model and installation procedure so that if the refrigerant accidentally leaks out, its density does not reach the limit (and in the event of an emergency, measures can be made before injury can occur).

ASHRAE and the International Mechanical Code of the ICC as well as CSA provide guidance and define safeguards related to the use of refrigerants, all of which define a Refrigerant Concentration Level (RCL) of 25 pounds per 1,000 cubic feet for R410A refrigerant. For additional guidance and precautions related to refrigerant safety, please refer to the following documents:

International Mechanical Code 2009 (IMC-2009) (or more recently revised) ASHRAE 15 ASHRAE 34

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.

Use a tube cutter when cutting the tubing, and be sure to remove any flash. This also applies to distribution joints (optional).

When bending tubing, use a bending radius that is 4 times the outer diameter of the tubing or larger.

Use sufficient care in handling the tubing. Seal the tubing ends with caps or tape to prevent dirt, moisture, or other foreign substances from entering. These substances can result in system malfunction.

Unit: in. (mm)

OMaterial

over 5/128 (1.0)

1/2 H, H

7/8 (22.22) 1 (25.4) 1-1/8 (28.58) 1-1/4 (31.75) 1-1/2 (38.1) 1-5/8 (41.28)

5/128 (1.0) 5/128 (1.0) 5/128 (1.0) 3/64 (1.1)

over 3/64 (1.15)

Unit: in. (mm)

over

3/64 (1.20)

Copper tube

CAUTION

Outer diameter 1/4 (6.35) 3/8 (9.52) 1/2 (12.7) 5/8 (15.88) 3/4 (19.05)

Wall thickness 1/32 (0.8) 1/32 (0.8) 1/32 (0.8) 5/128 (1.0)

Material

Outer diameter

Wall thickness

1-2.

Prevent impurities including water, dust and oxide from entering the tubing. Impurities can cause R410A refrigerant deterioration and compressor defects. Due to the features of the refrigerant and refrigerating machine oil, the prevention of water and other impurities becomes more important than ever.

2. Be sure to recharge the refrigerant only in liquid form.

2-1.

Since R410A is a non-azeotrope, recharging the refrigerant in gas form can lower performance and cause defects in the unit.

2-2. nce decreases when gas leaks, collect the remaining

Since refrigerant composition changes and performa refrigerant and recharge the required total amount of new refrigerant after fixing the leak.

3. Different tools required

3-1.

Tool specifications have been changed due to the characteristics of R410A. Some tools for R22- and R407C-type refrigerant systems cannot be used.

R407C tools

New

Item

Manifold gauge Yes No Types of refrigerant, refrigerating machine

Charge hose Yes

Vacuum pump Use a conventional vacuum pump if it is equipped

Leak detector Leak detectors for CFC and HCFC that

Flaring oil For systems that use R22, apply mineral oil (Suniso oil)

* Using tools for R22 and R407C and new tools for R410A together can cause defects.

compatible

tool?

with R410A?

Yes

Yes No

Yes

oil, and pressure gauge are different.

To resist higher pressure, material must be changed.

with a check valve. If it has no check valve, purchase and attach a vacuum pump adapter.

react to chlorine do not function because R410A contains no chlorine. Leak detector for HFC134a can be used for R410A.

to the flare nuts on the tubing to prevent refrigerant leakage. For machines that use R407C or R410A, apply synthetic oil (ether oil) to the flare nuts.

Remarks

Manifold gauge

Vacuum pump

Outlet Inlet

iii

3-2. Use R410A exclusive cylinder only.

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.

2. Existing tubing cannot be used (especially R22).

Completely cleaning out residual refrigerating

machine oil is impossible, even by flushing.

Val ve

Single-outlet valve

(with siphon tube) Liquid refrigerant should be recharged with the cylinder standing on end as shown.

Liquid

3. Refrigerating machine oil differs (R22).

Since R22 refrigerating machine oil is mineral oil, it does not dissolve in R410A. Therefore, refrigerating machine oil discharged from the compressor can cause compressor damage.

R22 refrigerating machine oil Mineral oil (Suniso oil)

R407C refrigerating machine oil Synthetic fluid (ether oil)

R410A refrigerating machine oil Synthetic fluid (ether oil)

—

Section 1: CONTROL FUNCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

2. Selecting Outdoor Unit for Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

3. Compressor Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

4. Special Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11

5. Other Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-16

6. Operation of Solenoid Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-17

7. Outdoor Unit Electronic Control Valves [MOV1, MOV2, MOV4] . . . . . . . . . . . . . . . . . . . . 1-19

8. Outdoor Fan Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-21

9. Demand Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-22

10. Indoor Unit Control of the Electronic Control Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-23

11. Solenoid Valve Kit Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-25

12. Indoor Special Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-26

13. Discharge Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-27

14. Current Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-28

15. Low Oil Alarm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-29

16. Pressure Sensor Failure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-30

17. Backup Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-31

18. Service Maintenance Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-33

19. Other Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-36

Section 2: OUTDOOR UNIT REPAIR PROCEDURES . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

1. Removing Panels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

2. Removing Electrical Component Box and Duct . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

3. Discharging Compressor Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5

4. Backup Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6

5. Recovering Refrigerant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9

6. Checking for Leakage After Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-14

7. Evacuating System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-15

8. Charging Compressor Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-16

9. Pumping Out Refrigerant from Outdoor Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-20

10. Compressor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-23

11. High and Low Pressure Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-35

12. Replacing 4-way valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-36

Section 3. OUTDOOR UNIT MAINTENANCE REMOTE CONTROLLER . . . . . . . . . . . . 3-1

1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2

2. Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3

3. Ordinary Display Controls and Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4

4. Monitoring Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9

5. Outdoor Unit Alarm History Monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11

6. Mode Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12

Section 4. REMOTE CONTROLLER FUNCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

1. Simple Settings Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2

2. Detailed Settings Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4

3. Remote Controller Servicing Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-15

Section 5. TROUBLE DIAGNOSIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1

1. Contents of Remote Controller Switch Alarm Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2

2. Outdoor Unit Control Panel LED Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4

3. Remote Controller Servicing Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5

4. 3-WAY VRF Alarm Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7

5. Blinking Inspection Display on the Remote Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-27

6. Inspection of Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-28

7. Test Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-29

8. Thermister Characteristics Curve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-30

3-WAY VRF SYSTEM

Contents

Control Functions

1. CONTROL FUNCTIONS

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

2. Selecting Outdoor Unit for Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

3. Compressor Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

4. Special Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11

5. Other Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-16

6. Operation of Solenoid Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-17

7. Outdoor Unit Electronic Control Valves [MOV1, MOV2, MOV4] . . . . . . . . . . . . . . . . 1-19

8. Outdoor Fan Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-21

9. Demand Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-22

10. Indoor Unit Control of the Electronic Control Valve . . . . . . . . . . . . . . . . . . . . . . . . . 1-23

11. Solenoid Valve Kit Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-25

12. Indoor Special Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-26

13. Discharge Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-27

14. Current Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-28

15. Low Oil Alarm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-29

16. Pressure Sensor Failure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-30

17. Backup Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-31

18. Service Maintenance Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-33

19. Other Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-36

1 - 1

3-WAY VRF SYSTEM

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. is set to “1” includes the CCU (command controller unit) functions that are used to control the entire system. As a result, the system will not operate if no outdoor unit has been set as unit No. “1.”

Required settings for Test Run

Outdoor unit No. 1 Outdoor unit Nos. 2

At time of shipment On-site setting At time of shipment On-site setting System address 1 System 1 ~ 30 1 Not necessary No. of indoor units 1 1 ~ 40 units 1 Not necessary No. of outdoor units 1 1 ~ 3 units 1 Not necessary Unit No. 1 Unit No. 1 1 Unit Nos. 2

This system can be expanded to connect a maximum of 3 outdoor units. (The system maximum capacity is 24 To n. )

The CCU functions are disabled at all units except the unit that is set as unit No. 1. Therefore no problems will result even if the system address, No. of indoor units, and No. of outdoor units settings are made at the other units. However, making these settings may be convenient for manual backup operation, as it eliminates the necessity of making the settings again if unit No. 1 fails. (If unit No. 1 fails, and the power supply to it is interrupted, it will be necessary to set a different unit as unit No. 1 in order to use manual backup operation.)

Control Functions

1 - 2

3-WAY VRF SYSTEM

2. Selecting an Outdoor Unit for Operation

Control Functions

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. 1, by using the outdoor unit maintenance remote controller to change the outdoor unit EEPROM settings.

* For information concerning EEPROM settings, refer to the field application functions.

2-2. Delayed Start of Outdoor Units

(1) Delayed start of outdoor units in the same system If it is necessary to operate the compressors simultaneously at multiple outdoor units, each outdoor unit will

start, beginning with unit No. 1, after a delay of a number of seconds equivalent to the outdoor unit address. The units do not start simultaneously.

This is in order to reduce the load on the power receiving equipment.

Outdoor unit

address 1

Starts after 1 second Starts after 2 seconds

(2) Delayed start for each system At the time of factory shipment, delayed start for each system is not set to occur. Therefore when systems are

linked and multiple systems are selected for start simultaneously by the central control device, all systems will begin operating simultaneously. For this reason, a function is included to delay the start time for each system address when systems are linked and multiple systems are selected for start by the central control device. In order to enable this delay time, it must be set in the EEPROM for each system. Those systems where this setting has been made will start after a delay according to their system addresses.

* For information concerning EEPROM settings, refer to the field application functions.

Outdoor unit

address 2

2-3. Outdoor Unit Stop Rules

(1) Simultaneous stop of multiple outdoor units When all outdoor units, or multiple outdoor units, must stop, the units stop at the same time. However,

depending on the communications timing, a difference of approximately 10 seconds may occur.

(2) Stopping individual outdoor units

●

The last unit to stop operating is the outdoor unit that contains the inverter compressor with the shortest

amount of operating time.

●

If the indoor load decreases, and it becomes necessary to reduce the number of operating outdoor units, the

compressors are stopped individually, in sequence. When all compressors installed in an outdoor unit have stopped, that outdoor unit also stops.

1 - 3

3. Compressor Control

3-1. Compressors Mounted in the Outdoor Units

[U-72MF1U9, U-72MF1U9E, U-96MF1U9, U-96MF1U9E]

Capacity 72 96

Installed

compressor

Compressor 1 Rotary DC Inverter DC Inverter

Compressor 2 Scroll

–

hp = horsepower

Compressor 2 Compressor 1Compressor 1

5 hp

Constant

speed

3-WAY VRF SYSTEM

Control Functions

INVINV

Type 96Type 72

3-2. Compressor Selection Rules

Because all outdoor units in this system contain an inverter compressor, ordinarily there is no absolute order of priority for compressor operation.

(1) Normal compressor operation sequence (set at time of shipment) At least one inverter compressor is always operating in order to make fine adjustments to the system

lower-limit capacity. When multiple outdoor units are connected, each unit contains an inverter compressor. Therefore, the inverter which operates is the inverter with the shortest amount of operating time. After the first inverter compressor has started, the remaining inverter compressors and constant-speed compressors start operating in order of the compressors which have the shortest amount of operating time.

* Immediately after installation, all compressors have an operating time of zero. In this case, the compressors

start in the following sequence: Inverter compressor > Constant-speed compressor.

<Details> The A/C units are selected with consideration for the maximum load. Therefore, in most cases the maximum

capacity is not required. Ordinarily, the operating range of an inverter compressor is approximately 25 Hz – 90 Hz, however operating efficiency declines somewhat in the high-frequency operating range. With consideration for these characteristics, control of inverter compressors in this system is divided into two ranges, according to the frequencies. Ordinarily, for reasons of efficiency, the upper limit for operation is approximately 50 Hz. If greater capacity is required, the next compressor is started. When all compressors are operating and greater capacity is required, the inverter compressors are operated at frequencies above approximately 50 Hz. This control may increase the lifetimes of the inverter compressors and refrigerant oil.

* If the number of connected outdoor units is small, the number of inverter compressors is also small. Therefore,

the compressors may operate at a high frequency even when the load is not large.

(2) Sequential operation beginning from unit No. 1 By using the outdoor unit maintenance remote controller to change the outdoor unit EEPROM settings, it is

possible to start the units in sequence, beginning from unit No. 1. * For information concerning EEPROM settings, refer to the field application functions.

1 - 4

3-WAY VRF SYSTEM

3. Compressor Control

Control Functions

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. Fine adjustments to system capacity control are made by the inverter compressors. (Depending on the conditions, all inverter compressors may be operating for fine adjustment.)

3-4. Inverter Compressor Capacity Control

(1) The inverter compressor has a center limit value and upper limit value for the operating frequency. These limits

are set for each outdoor unit capacity.

(2) The inverter frequency during operation may be lower than the frequency listed above due to overload current

protection control. In this case, the inverter frequency lower limit is 22 Hz.

* If Quiet mode is selected, the inverter may stabilize at a frequency lower than those stated above.

For information about Quiet mode, refer to the field application functions.

3-5. Forced Compressor Stop

After a compressor stops, it will not start for a period of 3 minutes (3 minutes forced OFF). However, this does not apply when the compressor was forced to stop as the result of a control operation during the special controls (start control, defrost control, refrigerant oil recovery control, etc.) which are described later.

3-6. Roadmap Control

(1) The below controls are performed according to the pressure sensor on the outdoor unit, and the 2 temperature

sensors attached to the indoor unit heat exchanger. * With roadmap control, the pressure detected by the pressure sensor is converted to saturation temperature.

A temperature that has been converted to saturation temperature is called the pressure sensor temperature. (2) These controls are performed every 30 seconds. (3) The temperatures used to determine the area (A, AB, B, C) for the evaporation temperature control shown in

the figure on the next page, and for condensation temperature control, may vary depending on the relationships among factors including the difference between the room temperature setting and the indoor unit air intake temperature (= air intake temperature difference) and the difference between the air discharge temperature

setting and the air discharge temperature (= air discharge temperature difference). (4) Definitions of evaporation temperature and condensation temperature Evaporation temperature (Te): Lowest heat exchanger temperature (E1, E3) at any indoor unit

Condensation temperature (Tc): Highest temperature among the outdoor unit pressure sensor temperature and

the heat exchanger temperatures (E1) at all indoor units where the heating thermostat is ON. Ordinarily, this is the outdoor unit pressure sensor temperature. (If multiple outdoor units are connected, this is the highest outdoor unit pressure sensor temperature.)

* E3 temperature is not used for condensation temperature detection, because it may indicate the temperature

of superheated gas.

1 - 5

3-WAY VRF SYSTEM

3. Compressor Control

3-6-1. Evaporation Temperature (Te) Control: Control of Indoor Units Operating in Cooling Mode

60.8

˚F

Horsepower increase permitted

51.9

51.8 Horsepower increase permitted

41.1

41.0 Horsepower increase prohibited

35.6

Horsepower decrease

35.4

Depending on the maximum requirement level of the indoor unit, the judgment

temperatures for each area may vary as shown in the figure (example).

Area A

Area AB

Area B

Area C

(1) For indoor units that are operating in Cooling mode, if one unit is selected for a test run, then the air

intake temperature difference (difference between the room temperature setting and indoor unit air intake temperature) is ignored, and areas B and C are considered to be area A for control purposes. (This is used for additional charging, test run checks, etc.) For this reason, vapor may be discharged if the test run continues for a long period of time, however this does

not indicate a problem. In addition, the test run is canceled automatically after 1 hour. (2) Even within the same area, the compressor capacity varies depending on the refrigerant temperature. (3) For 6 minutes after the compressors start, area C is considered to be area B for control purposes. (4) During special control, control of the compressor capacity according to Te is not performed. (5) If the thermostat turns OFF while Te is within area C, the next time the compressor starts it may restart from a

lower capacity. (6) When the area changes to area C, area C is considered to be area B for control purposes for the first 6

minutes, even if the horsepower is the minimum value within the range where capacity control is possible

(operation with inverter frequency of 25 Hz only). Subsequently if C area continues, the thermostat turns OFF.

53.6

51.8

45.5

Maximum requirement level [L]

41.0

35.6

Control Functions

1 - 6

3. Compressor Control

3-6-2. Condensation Temperature (Tc) Control:

Control when there are indoor units operating in Heating mode

3-WAY VRF SYSTEM

Control Functions

PX = 125.6 ˚FPXThermostat OFF

–0.1

Horsepower decrease

118.5

118.4 Horsepower increase

prohibited

116.6

116.4 Horsepower increase

permitted

113.0

112.8 Horsepower increase

permitted

Depending on the maximum requirement level of the indoor unit, the judgment temperatures for each area may vary as shown in the figure (example).

Area D

Area C

Area B

Area AB

Area A

109.4

107.6100.4

98.6 0

Maximum requirement level [L]

15 30

118.4

116.6

(1) For indoor units which are operating in Heating mode, if one unit is selected for a test run, the air intake

temperature difference is ignored, however Tc control is performed according to the figure above in order to

prevent excessive load. (This is used for test run checks, etc.) (2) Even within the same area, the compressor capacity varies depending on the refrigerant temperature. (3) Temperature PX is the coefficient value used to correct for any deviation with the high pressure or condensation

temperature. It may vary. (At the time of shipment it is 125°F.) (4) If the condensation temperature (Tc) enters area D and the thermostat turns OFF, the next time the compressor

starts it may restart from a lower capacity. (5) When the area changes to area C, area C is considered to be area B for control purposes for the first 6

minutes, even if the horsepower is the minimum value within the range where capacity control is possible

(operation with inverter frequency of 25 Hz only). Subsequently if C area continues, the thermostat turns OFF.

3-6-3. Control of condensation temperature and evaporation temperature during mixed cooling/heating

operation

During mixed cooling/heating operation, the control maintains a heat balance with a target evaporation temperature (Te) for the Cooling mode indoor units of 35 ~ 42°F and a target condensation temperature (Tc) for the Heating mode indoor units of 116 ~ 118°F.

Heat balance control is performed by varying the compressor capacity and heat discharge (heat intake) of the heat exchanger.

(1) Increasing/decreasing the compressor capacity

• When evaporation temperature (Te) is high and condensation temperature (Tc) is low

This occurs when both the cooling capacity (heat intake) and the heating capacity (heat discharge) are low. The compressor capacity and the circulation flow of refrigerant are increased in order to lower the evaporation temperature (Te) and raise the condensation temperature (Tc).

• When evaporation temperature (Te) is low and condensation temperature (Tc) is high

This occurs when both the cooling capacity (heat intake) and the heating capacity (heat discharge) are high. The compressor capacity and the circulation flow of refrigerant are decreased in order to raise the evaporation temperature (Te) and lower the condensation temperature (Tc). * Under conditions other than those listed above, the capacity of the outdoor unit heat exchanger is adjusted.

In some cases the heat exchanger capacity may also be adjusted at the same time when the compressor capacity is varied.

1 - 7

3. Compressor Control

Compressor Control Table

Low Condensation Temp. [Tc] High

3-WAY VRF SYSTEM

Control Functions

AUP

High

Evaporation Temp. [Te]

Low

slow_UP Target

not_UP

STOP

DOWN

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)

• Primarily when both the evaporation temperature (Te) and condensation temperature (Tc) are high

This occurs when the cooling capacity (heat intake) is low and the heating capacity (heat discharge) is high. The outdoor heat exchanger capacity is increased, increasing the system condensation capacity and lowering the condensation temperature (Tc). The amount of heat discharge at the outdoor unit heat exchanger increases, increasing the heat intake at the Cooling mode indoor units and lowering the evaporation temperature (Te).

• 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 decreased, decreasing the system condensation capacity and raising the condensation temperature (Tc). The amount of heat discharge at the outdoor unit heat exchanger decreases, decreasing the heat intake at the Cooling mode indoor units and raising the evaporation temperature (Te).

Outdoor Unit Heat Exchanger Control Table (when the outdoor unit heat exchanger is functioning as a condenser)

High

Evaporation Temp. [Te]

Low

Low Condensation Temp. [Tc] High

STAY

DOWN

Target

STAY

Compressor stop

STAY

1 - 8

3-WAY VRF SYSTEM

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). The amount of heat intake at the outdoor unit heat exchanger increases, increasing the heat discharge at the Heating mode indoor units and raising the condensation temperature (Tc).

• Primarily when both the evaporation temperature (Te) and condensation temperature (Tc) are high

This occurs when the cooling capacity (heat intake) is low and the heating capacity (heat discharge) is high. The outdoor heat exchanger capacity is decreased, decreasing the system evaporation capacity and lowering the evaporation temperature (Te). The amount of heat intake at the outdoor unit heat exchanger decreases, decreasing the heat discharge at the Heating mode indoor units and lowering the condensation temperature (Tc).

Outdoor Heat Exchanger Control Table (when the outdoor heat exchanger is functioning as an evaporator)

Low Condensation Temp. [Tc] High

Control Functions

High

Evaporation Temp. [Te]

Low

STAY

Target

STAY

DOWN

STAY

Compressor stop

STAY

3-6-4. Protection control

Protection control consists of 2 types of protection: air discharge temperature protection and current protection. The limit values from this protection control are incorporated into the output compressor capacity increase/decrease values that were calculated from control based on the temperature at the indoor unit heat exchanger (roadmap control).

* In some cases, the control shown below may stop the compressor, issue a warning, or reduce the compressor

capacity.

(1) Air discharge temperature protection During operation when only a single outdoor unit is installed, the air discharge temperature level is determined

(the highest value is used), and the compressor capacity is limited, by using the air discharge temperature of

the operating compressor (as shown in the tables below).

Air discharge temperature level: Highest level among the air discharge temperature levels of all compressors

Air discharge temp. level Discharge temp. Horsepower limit

The values shown in the table above are reduced to the values calculated by roadmap control.

212 ~ Less than 217

208 ~ Less than 212

221

219

217

Less than 208

1 - 9

Decrease by 2 horsepower

Decrease by 1 horsepower

Decrease by 0.5 horsepower

Prohibit horsepower increase

Permit horsepower increase

No control

3-WAY VRF SYSTEM

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.

Primary current Secondary current

Control Functions

– 75 or (302 °F) Thermostat OFF

– 48 or above Thermostat OFF

26.5 25 ~ 32.5 Horsepower decreased

25 24 ~ Less than 25 Prohibit horsepower increase

24 Less than 24 Permit horsepower increase

3-6-5. Roadmap control after trip

When restarting after trip stop occurs, the horsepower may increase slowly depending on the trip counter value. (1) If Trip counter = 1, the horsepower increases at a speed that is 1/2 of ordinary roadmap control. (2) If Trip counter = 2, the horsepower increases at a speed that is 1/3 of ordinary roadmap control. The trip counter is cleared if no trip occurs within 10 minutes after operation starts.

Operation stops instantaneously due

to activation of hybrid IC

Thermostat OFF. Operation stops for

100 ms for current protection

1 - 10

3-WAY VRF SYSTEM

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. System refrigerant oil recovery control

3. Defrost control

Control Functions

4-1. Tube Refrigerant Recovery Control

This control recovers refrigerant from the tubing when the microcomputer is initialized immediately after power-ON, after warning output occurs, and after a set amount of time has elapsed (standard = 60 minutes) when all outdoor units are stopped. This control is intended to recover refrigerant if refrigerant has accumulated somewhere in the tubing when the units have been stopped for long periods, as well as to compensate for tubing thermal loss during heating start, and is also used for oil recovery.

(1) Control when the outdoor unit heat exchanger is acting as a condenser (when all units are in Cooling mode or

at start of mixed operation when the cooling load is high)

Control time 60 seconds Outdoor units All outdoor units operate at maximum horsepower. Electronic control valve Valves at all indoor units operate at a ﬁ xed pulse according to the indoor unit capacity.

Indoor units

* When the above operation is ﬁ nished, normal operation starts at the horsepower determined by the indoor units

where thermostats are ON.

RAP valve kit Valve kits at all indoor units operate in Cooling mode (ON status).

Fan

Fan operates at the set fan speed, stops, or operates at L speed, depending on the indoor unit operation mode.

(2) Control when outdoor unit heat exchanger is acting as a condenser (when all units are in Cooling mode or at

start of mixed operation when cooling load is high)

Control time Minimum 1 min – Maximum 10 min [until max (pressure sensor temp., E1) ≥ 95°F] Outdoor units All outdoor units operate at maximum horsepower. Electronic control valve Valves at all indoor units operate at 480 pulses.

Indoor units

* When the above operation is ﬁ nished, normal operation starts at the horsepower determined by the indoor units

where thermostats are ON.

RAP valve kit Valve kits at all indoor units operate in heating mode (ON status).

Fan

Fan operates at the set fan speed, stops, or operates at L speed, depending on the indoor unit operation mode.

4-2. System Refrigerant Oil Recovery Control

4-2-1. System refrigerant oil recovery cycle

This control is performed using the cooling cycle during cooling operation and using the heating cycle during heating operation.

4-2-2. Start of system refrigerant oil recovery control

When the oil level in an operating compressor changes to 0, the compressor stops after 120 seconds. If this compressor repeats this operation 3 times and the oil level does not reach 2, system refrigerant oil recovery control is started.

* When the compressor has stopped because the oil level is 0, a count is added to the alarm counter. The counter

for this compressor is not cleared unless the oil level for that compressor reaches 2, or else alarm output occurs.

1 - 11

3-WAY VRF SYSTEM

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) → 3-minute stop → Normal operation

(2) Cooling cycle

Control time Maximum 3 minutes (Stops once before and once after control.)

Outdoor units All outdoor units operate at maximum horsepower.

Electronic control valve Valves at all indoor units operate at a ﬁ xed pulse according to the indoor unit capacity.

Indoor units

(3) Heating cycle

Indoor units

RAP valve kit Valve kits at all indoor units operate in Cooling mode (OFF status.)

Fan

Control time Maximum 3 minutes (Stops once before and once after control.) Outdoor units All outdoor units operate at maximum horsepower. Electronic control valve Valves at all indoor units operate at 480 pulses.

RAP valve kit Valve kits at all indoor units operate in Heating mode (ON status).

Fan

Fan operates at the set fan speed, stops, or operates at L speed, depending on the indoor unit operation mode.

Control Functions

4-3. Defrost Control

4-3-1. Defrost control method

This system uses the following 2 defrost methods. (1) If there is 1 outdoor unit in the refrigerant system: Reverse cycle defrost (2) If there are 2 or more outdoor units in the refrigerant system: Outdoor unit cycle defrost

4-3-2. Constraint conditions

(1) Frost detection does not occur for 5 minutes after operation starts. (2) Defrost does not begin again for 35 minutes of A/C operation after defrost was once completed. (3) If all indoor units are stopped while defrost control is in effect, or if the outdoor unit is stopped due to protection

control or another reason, then defrost control will not start for a minimum of 10 minutes after restart occurs.

1 - 12

3-WAY VRF SYSTEM

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.

Condition 2: L1 line or below is detected for a total of 60 minutes when the compressor is operating.

Heat exchange liquid temperature ˚F

Defrosting operation

42.8

end temperature

(The end temperature is different from the above detection temperature.)

Control Functions

–6.5

–9

–13

The frost detection area is located under the thick lines

External temperature ˚F

4-3-4. Outdoor units where defrost occurs

Even if the total time has not reached 35 minutes, if there is 1 or more outdoor units that fulfills the defrost detection conditions, all operating outdoor units perform defrost control at the same time.

* Defrost control is also performed at outdoor units where the outdoor unit heat exchanger is not functioning as an

evaporator (such as stopped outdoor units).

4-3-5. Reverse cycle defrost

Reverse cycle defrost is performed in systems where only 1 outdoor unit is connected to the refrigerant system.

• Defrost flow E: Evaporator operation C: Condenser operation E→C: Switching from evaporator operation to condenser operation C→E: Switching from condenser operation to evaporator operation

Defrost preparation Defrost in progress Defrost end

Outdoor unit status E→CE

Stopped indoor units E E E E

Indoor units where fan is operating E E E E

Cooling mode indoor units

Heating mode indoor units

Thermostat ON E E E E Thermostat OFF E E E E Thermostat ON C→EC Thermostat OFF C→EC

Compressor Stopped Operating Operating Stopped

Time 1 min 1 min Max. 12 min 1 min

→

Defrost end

→

EE E

→

EE E

judgment

C→E

→ →

C C

* With type E1, E → C occurs for 3 minutes after defrost ends. Therefore the thermostat remains OFF for 3

minutes.

1 - 13

3-WAY VRF SYSTEM

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. In this way, the other outdoor unit is heating the unit where defrost is occurring. When 1 outdoor unit completes defrost, the other outdoor unit performs defrost in the same way. Because the amount of time that the unit operates as an evaporator is very short, there is little danger of frost forming again quickly. Rather, because the heat source is very powerful, it is possible to shorten the defrost operating time.

(2) Defrost sequence Outdoor unit cycle defrost is always completed in 2 defrost operations. (A) When there are 2 outdoor units

Control Functions

Defrost

outdoor unit

First operation Second operation

Evaporator outdoor unit

Switch

Evaporator

outdoor unit

Defrost

outdoor unit

• Defrost flow E: Evaporator operation C: Condenser operation S: Shut off E→C: Switching from evaporator operation to condenser operation C→E: Switching from condenser operation to evaporator operation

Defrost

preparation

Outdoor unit(s) where defrost occurs ﬁ rst E→CC C→EE

Outdoor unit(s) where defrost occurs second E E

Stopped indoor units S S S S S

Indoor units where fan is operating S S S S S

Cooling mode indoor units

Heating mode indoor units

Compressor Operating Operating Stopped Operating Stopped

Thermostat ON E E E E E Thermostat OFF E E E E E Thermostat ON C C C C C Thermostat OFF C C C C C

Time 1 min Max. 7 min 1 min Max. 7 min 1 min

Defrost in

progress

Defrost end judgment

Switch

E→CC C→E or S

Defrost in

progress

Defrost end judgment

Defrost

preparation

E or S

* With type E1, E → C occurs for 3 minutes after defrost ends. Therefore the thermostat remains OFF for 3

minutes.

1 - 14

3-WAY VRF SYSTEM

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. However, if there is any other outdoor unit where the defrost end condition has not been met, defrost control continues for all outdoor units, and system defrost control is not ended.

Condition 2: The maximum defrost time listed in the table above has elapsed.

4-3-8. System defrost end

When all outdoor units where defrost control is in effect have met the defrost end conditions, defrost control is ended for the system.

Control Functions

1 - 15

5. Other Controls

5-1. Oil Control

5-1-1. Oil level

3-WAY VRF SYSTEM

Control Functions

Oil level

2 Sufficient

Meaning Oil state Assessment

This is the normal operating state of the system and not a problem.

Check that oil control recovers oil.

Check that system oil recovery control restores the oil level.

Slightly

low

Extremely

low

There is more than an adequate amount of oil in the compressor.

The compressor may contain an adequate amount of oil, but it may also contain less than an adequate amount of oil.

There is not enough oil in the compressor.

The compressor contains enough oil when the oil level is in the range between level 2 and until it has just become

1. Thus oil level 1 does not mean that the compressor is empty of oil. When the compressor reaches oil level 0 during operation, the system is likely to run out of oil within 5 to 10 minutes. Check for oil leaks and make sure that refrigerant pipes are intact.

5-1-2. Oil level detection

Excess oil in the compressor is sent by bypass via a capillary tube to the low-pressure circuit. The temperature detected by a temperature sensor is used to determine whether it is oil (warm) or refrigerant (cold).

5-1-3. Self-separator oil recovery control

* When a low oil level is detected, this control recovers the oil which has accumulated in that oil separator and

sends it to the compressor.

(1) Operation when oil level is 1 30 seconds after the oil level changes from 2 to 1, both the balance valve and recovery valve turn ON for up to

2 minutes. However, if the oil level becomes 2 during these 2 minutes, this control is stopped. When this control has been stopped, it will not restart for 3.5 minutes unless the oil level becomes 0.

(2) Operation when oil level is 0 Both the balance valve and recovery valve turn ON and remain ON.

5-1-4. Unit refrigerant oil recovery control – utilizing balance tubes

* If the low oil level continues, that outdoor unit (oil-receiving outdoor unit) receives a supply of oil from operating

outdoor units where the oil level is not low (oil-supply outdoor units).

(1) Control at the oil-supply outdoor unit begins 3 minutes after the oil level at the outdoor unit changes to 0 or 1.

Oil supply is performed for a maximum of 5 minutes from each unit.

(2) When oil supply is ended, oil supply from that outdoor unit will not occur again for a period of [(No. of outdoor

units – 1) x 5 minutes]. In addition, oil supply is ended if the oil-receiving outdoor unit oil level changes to 2, or if the oil-supply outdoor unit oil level becomes low.

(3) The supply of oil is received from 1 unit at a time, in sequence, according to the order of priority of their inverter

compressors.

(4) Operation during unit refrigerant oil recovery

(A) Oil-receiving outdoor unit

The recovery valve turns ON and remains ON. * Because self-separator oil recovery may occur simultaneously at the same unit, both the balance valve

and recovery valve turn ON at this time.

(B) Oil-supply outdoor unit

The balance valve turns ON and remains ON. The bypass valve repeatedly turns ON and OFF according to a fixed cycle. * When the balance valve is ON, the oil in the oil separator is discharged into the balance tube. The bypass

valve releases high-pressure gas which forces this oil toward the oil-receiving outdoor unit, and flushes out the balance tubes. The operation of this bypass valve allows oil to be supplied even when there is a difference in height between the outdoor units.

5-1-5. Indoor unit refrigerant oil self-recovery control

Refer to the items concerned with indoor unit special control.

1 - 16

3-WAY VRF SYSTEM

6. Operation of Solenoid Valves

Control Functions

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.

(1) The OFF conditions take priority over the ON conditions for this valve. (2) This valve is OFF when the outdoor unit is stopped. (3) This valve is ON when special control is in progress. (4) Control during normal operation

(A) Cooling operation

●

This valve turns ON when symptoms of insufficient refrigerant gas occur at an

indoor unit.

●

This valve turns ON when the outdoor air temperature is 59°F or below. (Under

these conditions the high pressure is low and refrigerant flow becomes poor.)

●

This valve turns OFF when symptoms of refrigerant overcharge are detected at

the outdoor unit.

(B) Mixed cooling/heating operation

●

The RCV turns ON at stopped outdoor units when the heat exchanger at

another outdoor unit is functioning as a condenser.

6-2. Refrigerant Balance Valve [RBV] – Gas Purge Valve

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 an evaporator. When the valve determines that there are signs of excess refrigerant, refrigerant is recovered at the receiver tank. This valve is ON during heating operation and when the outdoor unit heat exchanger is functioning as an evaporator during mixed heating/cooling operation. It also turns ON in order to recover refrigerant at the outdoor unit after heating operation is stopped. * This valve is never ON at the same time as the RCV.

(1) The OFF conditions take priority over the ON conditions for this valve. (2) This valve turns ON for 30 – 50 seconds after the outdoor unit stops, and then turns OFF. (3) This valve turns ON once after the outdoor unit starts.

(A) Heating operation

●

This valve turns ON when poor refrigerant flow at an indoor unit is detected,

and when symptoms of overcharge are detected. After the valve turns OFF, it will not turn ON again for 15 minutes.

(B) Mixed heating/cooling operation

●

This valve turns ON when poor refrigerant flow at an indoor unit is detected,

and when symptoms of overcharge are detected, if the heat exchanger at the

outdoor unit is functioning as an evaporator. (4) This valve turns OFF when an abnormal drop in discharge gas temperature is detected. (5) This valve turns OFF when a drop in the detected receiver tank temperature

continues for a set length of time, and when liquid back-flow is judged to be occurring.

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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. (B) This valve is ON when unit refrigerant oil recovery control is in progress (oil-supply unit). (C) This valve turns ON for 30 seconds each time a constant-speed compressor starts. (D) This valve turns ON for 60 seconds after defrost control ends.

6-4. Recovery Valve (ORVR)

This valve recovers refrigerant oil from the balance tube to the compressor. (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. (B) This valve is ON when unit refrigerant oil recovery control is in progress (oil-receiving unit). (C) This valve is ON when control for insufficient gas is in progress. (D) This valve turns ON for 60 seconds after a constant-speed compressor starts. (E) This valve turns ON for 120 seconds after defrost control ends. (F) This valve turns ON for 10 seconds after the outdoor unit stops. (G) This valve remains OFF at all times other than (A) – (F) above.

3-WAY VRF SYSTEM

Control Functions

6-5. Bypass Valve (BPV)

This valve flushes the oil from the balance tubes. In addition, it is used for recovering refrigerant from stopped outdoor units during cooling operation.

(1) When unit is stopped This valve is always OFF.

(2) When unit is operating This valve is ON at the oil-supply outdoor unit when unit refrigerant oil recovery control is in progress.

* This valve repeatedly turns ON/OFF at regular intervals during unit refrigerant oil recovery control. (It is not

constantly ON.)

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3-WAY VRF SYSTEM

7. Outdoor Unit Electronic Control Valves [MOV1, MOV2, MOV4]

Control Functions

7-1. Types of Electronic Control Valves

[U-72MF1U9, U-72MF1U9E, U-96MF1U9, U-96MF1U9E]

Capacity 72 96

Electronic control valve

Electronic control valve 1

Electronic control valve 2

Electronic control valve 4

Heat exchanger 1 valve

Heat exchanger 2 valve

For SC circuit

Heat exchanger 1 valve

Heat exchanger 2 valve

For SC circuit

7-2. Power Initialization

If no indoor units have started (even once) after the power was turned ON, the outdoor unit electronic control valve operates at 480 pulses.

7-3. Heat Exchanger Controlled by Each Electronic Control Valve

The configuration of the heat exchangers is different depending on the capacity of the outdoor unit.

Heat exchanger 1

Heat exchanger 2

Front

Type 72, 96

Operation of electronic control valves during normal unit operation

Heat exchanger status

All indoor units in Cooling mode

All indoor units in Heating mode

Mixed heating/ cooling operation

●

When all indoor units are operating in Cooling mode or Heating mode, all outdoor unit heat exchangers are used

Outdoor heat exchanger condenser

Outdoor heat exchanger evaporator

Condensor 480 480 Maximum ﬂ ow control Stopped 0 0 Refrigerant shut-off Evaporator 45~480 15~480 SH control Stopped 0 0 Refrigerant shut-off Condensor 50~480 50~480 Heat exchanger capacity control Stopped 0 0 Refrigerant shut-off Evaporator 45~480 15~480 SH control Stopped 0 0 Refrigerant shut-off

MOV1 MOV2 Remarks

if even one of the compressors in that outdoor unit is operating.

●

During mixed heating/cooling operation, the number of heat exchangers used varies according the conditions of

the indoor units. However, heat exchanger 1 at the outdoor unit which contains the inverter compressor with the lowest amount of operating time is always used.

●

SH control controls the difference between the liquid temperature and gas temperature to 2 ~ 10°F.

●

During heating mode SH operation, refrigerant may not flow to the heat exchanger.

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3-WAY VRF SYSTEM

7. Outdoor Unit Electronic Control Valves [MOV1, MOV2, MOV4]

Control Functions

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. When SC is small and the length of the tubing connecting the indoor and outdoor units is long, the pressure loss increases, possibly resulting in lower capacities. Therefore, MOV4 operates at the double tube near the discharge port of the outdoor unit in order to increase SC.

MOV4 uses the receiver tank detection sensor and low-pressure sensor located near the accumulator to

perform control in order to prevent liquid back-up.

Liquid refrigerant (SC = 0˚F)

Gas refrigerant returns to the accumulator.

Refrigerant on the outer side evaporates, cooling the liquid refrigerant on the inner side.

Liquid refrigerant (large SC)

Electronic control valve 4 (expansion valve) controls the flow.

(2) Operation when discharge temperature is high When the discharge temperature increases, the SC circuit electronic control valve opens to 480 pulses. This

intentionally causes a mild liquid back-up, cooling the compressor. This operation takes priority over operation intended to increase SC. It is performed at top priority in all operating modes.

Liquid refrigerant returns to the accumulator.

Liquid refrigerant

Does not fully evaporate, resulting in liquid back-up.

Electronic control valve 4 opens to 480 pulses.

Liquid refrigerant

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3-WAY VRF SYSTEM

8. Outdoor Fan Control

Control Functions

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.

8-2. Outdoor Fan Min. Fan Mode and Max. Fan Mode

Min. fan mode Max. fan mode

Cooling operation

Heating operation 1 14

* Even if the fan mode is 0 during cooling operation, the fan mode may change to 1 at regular intervals for

temperature protection of the inverter hybrid IC.

Outdoor air temp. > 59°F: 1 Outdoor air temp. ≤ 59°F: 0

8-3. Fixed Initial Fan Mode

For the first 30 seconds after operation starts, the mode is fixed at the initial mode which was calculated from the relationship between the outdoor air temperature and the outdoor unit horsepower. If the outdoor unit horsepower changes dramatically, the initial mode may be recalculated and may be again fixed for 30 seconds.

8-4. Operation after Fixed Initial Fan Mode

After the fixed initial fan mode, the fan mode is increased or decreased according to the operating conditions. (1) Cooling mode at all indoor units, or else mixed heating/cooling operation when the outdoor unit is functioning

as a condenser (A) Fan mode is increased when the pressure sensor temperature is high, and is decreased when the pressure

sensor temperature is low. * The fan mode is always increased when the pressure sensor temperature is 122°F or higher.

(B) The fan mode may be decreased when symptoms of insufficient gas are detected at an indoor unit.

(2) Heating mode at all indoor units, or else mixed heating/cooling operation when the outdoor unit is functioning

as an evaporator (A) If the condensation temperature is low, the fan mode is increased at regular intervals. (B) If the condensation temperature is high, the fan mode is decreased in order to prevent excessive loads. (C) The fan mode may be increased when the outdoor liquid temperature drops to 44°F or below.

8-5. Snow Removal Control

(1) When the outdoor air temperature is 50°F or below, the fan operates for 30 seconds every 2 hours in fan mode

8, even when the outdoor unit is stopped or the heat exchanger is not in use. This control is intended to prevent snow from accumulating on stopped fans. (Because the outdoor air temperature cannot be accurately detected when the unit is stopped, a higher outdoor air temperature is used for the control condition, in order to ensure correct operation.)

(2) If the fan mode becomes 0 during cooling operation, the fan mode is changed to 1.

* This control is predictive control. Use a snowfall sensor as necessary according to the installation conditions.

8-6. When the Compressor Magnet Switch Seizing Alarm Occurs

Because there is the possibility that the high pressure has increased, the fan operates in Max. fan mode.

8-7. Other

This unit includes settings for high static-pressure and for Quiet mode. For information about these settings, refer to the field application functions.

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3-WAY VRF SYSTEM

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.

Control Functions

Demand setting

Contact 1 Contact 2

¯¯ {¯ ¯{ {{

: Input present

{

No control Operates to maximum capacity. Rated current — Operates at up to 70% of rated current — Shutdown state —

: Input not present

Control Demand meaning

* The rated current indicates the current value that is listed in the catalog or similar material. If the capacity of this

device is insufficient, the inverter compressor raises its operating frequency in order to maintain capacity. For this reason, it is capable of operating at a current which exceeds the rated current (up to approximately 130%).

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+ 118 hidden pages

Panasonic 3-Way Service Manual

SERVICE MANUAL

CONTENTS

1. CONTROL FUNCTIONS

1. Introduction

2. Selecting an Outdoor Unit for Operation

3. Compressor Control

4. Special Controls

5. Other Controls

6. Operation of Solenoid Valves

7. Outdoor Unit Electronic Control Valves [MOV1, MOV2, MOV4]

8. Outdoor Fan Control

9. Demand Control