Refrigerant R410A is used in the outdoor units.
* Salt-Air Damage Resistant Specifications.
Indoor Units
4-Way Air Discharge
X
Semi-Concealed
4-Way Air Discharge
XM
Mini Semi-Concealed
1-Way Air Discharge
A
Semi-Concealed
Concealed Duct Type
U
Slim Concealed
UM
Duct Type
Concealed-Duct High
D
Static Pressure
Ceiling-Mounted
T
CHDX07263
CHDXR07263
7
AHX0752
UHX0762
UMHX0762
**
9Class
AHX0952
UHX0962
UMHX0962
9672Class
CHDX09663
CHDXR09663
1215182419364854
XHX1252
XMHX1252
AHX1252
UHX1262
UMHX1262
THX1252
UHX1562
UMHX1562
XHX1852
XMHX1852
UHX1862
UMHX1862
THX1852
MULTI SYSTE
XHX2452
UHX2462 UHX3662 UHX4862 UHX5462
THX2452
XHX3652
DHX4852DHX3652
M
Wall-Mounted Type
K
Floor-Standing Type
F
Concealed-Floor
FM
Standing Type
**
Necessary to install the External Electronic Expansion Valve Kit (Optional:ATK-SVRK56BA).
85464849280000
KHX0752 KHX0952
FHX0762 FHX0962
FMHX0762
FMHX0962
KHX1252
FHX1262
FMHX1262
FHX1562
FMHX1562
KHX1962KHX1862
FHX1862
FMHX1862
KHX2452
**
FHX2462
FMHX2462
REFERENCE NO.
SM830180-00
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.
Carefully read this instruction booklet before beginning.
Follow each installation or repair step exactly as shown.
Observe all local, state, and national electrical codes.
This symbol refers to a hazard or
unsafe practice which can result
in personal injury or product or
property damage.
In Case of Improper Installation
When Wiring
ELECTRICAL SHOCK CAN CAUS
SEVERE PERSONAL INJURY OR DEATH.
ONLY A QUALIFIED, EXPERIENCED
ELECTRICIAN SHOULD ATTEMPT TO
WIRE THIS SYSTEM.
E
• 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.
•
When Installing…
…In a Room
Properly insulate any tubing run inside a room to preven
“sweating” that can cause dripping and water damage to
walls and floors.
t
…In Moist or Uneven Locations
…
…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.
•
• 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 Servicing
•
• Keep your fingers and clothing away from any moving
parts.
•
•
• 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.
IMPORTANT!
For safe installation and trouble-free operation, you must:
Pay close attention to all warning and caution notices
given in this manual.
This symbol refers to a hazard or
unsafe practice which can result
in severe personal injury or death.
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.
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
Ground the unit following local electrical codes.
Connect all wiring tightly. Loose wiring may cause overheating at connection points and a possible fire hazard.
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 thin aluminum
fins on the air conditioner can cut your fingers.
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.
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.
Turn the power OFF at the main power box (mains)
before opening the unit to check or repair electrical parts
and wiring.
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.
CAUTION
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.
•
•
•
•
•
i
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 airconditioner, 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 off loor 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
ii
—
CONTENTS
—
Section 1: CONTROL FUNCTIONS .......................................... 1-1
17. Service Maintenance Functions .........................................
18. Other Functions ......................................................
1-30
1-32
1 - 1
W-2WAY ECO-i SYSTEM
1. Introduction
The W-2WAY ECO-i 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
Control Functions
1
System address
No. of indoor units
No. of outdoor units
Unit No.
Outdoor unit No.1
At time of shipmentAt time of shipment
1
1
1
1
On-site settingOn-site setting
System 1 ~ 30
1 ~ 40 units
1 ~ 3 units
Unit No. 1
Outdoor unit No. 2
1
1
1
1
Not necessary
Not necessary
Not necessary
Unit No. 2
This system can be expanded to connect a maximum of 3 outdoor units. (The max. system capacity shall be within
24 Ton.)
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.
1 - 2
W-2WAY ECO-i 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 unitOutdoor unit
address 1address 2
Starts after 1 secondStarts 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.
1
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.
In cooling mode, all inverter compressors in the outdoor units are designed to operate simultaneously
Therefore, all the outdoor units will stop at a time when any one unit is stopped. In heating mode, the out
door unit which has the inverter compressor with the shortest amount of operating time continues to run and
rest of the other outdoor units may be stopped.
1 - 3
.
-
3. Compressor Control
3-1. Compressors Mounted in the Outdoor Units
[CHDX07263, CHDX09663]
Capacity
7296
W-2WAY ECO-i SYSTEM
Control Functions
1
Installed
compressor
Compressor 1
Compressor 2
INV
Compressor 1
Type 72
Rotary
Scroll
DC InverterDC Inverter
–––
Constant
speed
Compressor 2
5 hp
hp = horsepower
INV
Compressor 1
Type 96
3-2. Compressor Selection Rules
In cooling mode, all inverter compressors in the outdoor units are designed to operate simultaneously. All the
inverter compressors will stop at a time when the outdoor is stopped accordingly. Constant-speed compressors
run in order of the shortest amount of operating time. In heating mode, the inverter compressor with the shortest
amount of operating time runs at first followed by the compressors in order of the shortest amount of operating
time including inverter units.
* 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 1 > Constant-speed compressor 2.
Examples of accumulated operating time: ODU=Outdoor Unit
Suppose the following tentative system.
Comp 1
Comp 2
ODU 1
100 hrs.
150 hrs.
ODU 2
70 hrs.
160 hrs.
Compressor Selection Sequence in Cooling Mode:
All the inverter compressors are firstly selected simultaneously.
Comp 1
Comp 2
ODU 1
1st
3rd
ODU 2
1st
4th
Compressor Selection Sequence in Heating Mode:
First, the inverter compressor with the shortest amount of operating time is selected. And then, the remained
other compressors are selected and start in the order of shortest amount of operating time
Comp 1
Comp 2
ODU 1
3rd
4th2nd
ODU 2
1st
.
1 - 4
W-2WAY ECO-i SYSTEM
3. Compressor Control
Control Functions
3-3. Compressor Capacity Control
The compressor operating conditions vary depending on the indoor unit operating conditions and the effects of
indoor heat load, outdoor 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.
* 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.
* If the Power Demand Mode is selected, the inverter may stabilize at a frequency lower than those stated
above. Refer to the Field Application Function for the detail.
3-5. Forced Compressor Stop
Once a compressor stops, it will not start for a period of 3 minutes (3-minute 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 mentioned Roadmap Control are performed according to the pressure sensor on the outdoor unit
and the 2 temperature sensors attached to the indoor unit heat exchanger coil.
* With the roadmap control in heating mode, the pressure detected by the pressure sensor at high pressure
side is converted to the saturation temperature. This converted saturation temperature is called the “High
Pressure Saturated Temperature”.
,
1
(2)
This control is performed every 15 seconds.
(3) The evaporation temperature control and the temperature used to determine the area (A, AB, B, C) for the con-
densation control shown in the figure on the next page, may vary depending on the relationships among factors
including the difference between the room temperature setting and the 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):
Condensation temperature (Tc): Highest temperature among the outdoor unit pressure sensor temperature and
* E3 temperature in heating mode is not used for the condensation temperature detection, because it may indi-
cate the temperature of superheated gas.
Lowest heat exchanger temperature (E1, E3) at any indoor unit
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. )
1 - 5
1
W-2WAY ECO-i 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
Area A
Area AB
Area B
Area C
53.6
51.8
45.5
0
Maximum requirement level [L]
15
41.0
35.6
30
Control Functions
* Depending on the maximum requirement level of the indoor unit, the judgement
temperatures for each area may vary as shown in the figure.
(1)
For indoor units that are operating in Cooling Mode, if one unit is selected for a test run mode, the room temperature control by the set temperature cannot be performed. Areas B and C are assumed to be area A for control
purposes, instead. By this reason, the compressor continues its operation regardless of the low evaporation
temperature (This is used for additional charging of refrigerant, test run checking etc.) Vapor may be discharged
if the test run continues for a long time. However, this does not indicate problems.
(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 min-
utes, 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.
1 - 6
3. Compressor Control
W-2WAY ECO-i SYSTEM
Control Functions
3-6-2.
Condensation Temperature (Tc) Control:
Control of Indoor Units Operating either in Cooling Mode or Heating Mode
PX=125.6
* Depending on the maximum requirement level
of the indoor unit, the judgment temperatures
for each area may vary as shown in the figure
(example).
°F
PX –0.1
118.5
118.4
116.6
116.4
113.0
112.8
Thermostat OFF
Horsepower decrease
Horsepower increase
prohibited
Horsepower increase
permitted
Horsepower increase
permitted
Area D
Area C
Area B
Area AB
Area A
118.4
116.6
109.4
100.4
98.6
0
Maximum requirement level [L]
107.6
3015
(1) For indoor units which are operating in Heating mode, if one unit is selected for a test run, the air intake tem-
perature 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.
1
(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 127°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.
3-6-3. Protection control
Protection control consists of 2 types of protection: 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 coil (roadmap control).
In some cases, the control shown below may stop the compressor, issue a warning, or reduce the compressor
*
capacity.
(1)
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
5
4
3
2
1
0
Discharge temp. °F
221
219
217
212 ~ Less than 217
208 ~ Less than 212
Less than 208
Decrease by 2 horsepower
Decrease by 1 horsepower
Decrease by 0.5 horsepower
Permit horsepower increase (slowly)
No control
Horsepower limit
Prohibit horsepower increase
The values shown in the table above are reduced to the values calculated by roadmap control.
1 - 7
W-2WAY ECO-i SYSTEM
3. Compressor Control
(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.
Control Functions
1
Primary current
-
16.0A~
14.5A~
13.5A~
Secondary current
75.0A or (302°F)
16.5A
13.5A
13.0A
80H
z
90H
z
12.5A
12.0A
Inverter compressors stop (HIC auto. protection)
Inverter compressors stop (When 100ms is detected,
current protection works.)
Hz decrease in the inverter compressor
Prohibit Hz increase in the inverter compressor
Permit Hz increase in the inverter compressor
Control
3-6-4. Roadmap Control after Trip
When restarting after the 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 will be cleared if no trip occurs within 10 minutes after operation starts.
1 - 8
W-2WAY ECO-i 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.
4-way Valve Adjustment Control
2.
System refrigerant oil recovery control
3.
Defrost control
Control Functions
4-1. 4-way Valve Adjustment Control
When the microcomputer is initialized immediately after power-ON, after warning output, and all outdoor units are
kept stopped for a preset period (standard = 60 minutes) , the 4-way Valve Adjustment Control will be performed.
This control is intended to changeover the 4-way valve of outdoor unit. When the unit has been stopped for long
period, and if refrigerant has accumulated somewhere in the tubing, recovery of the refrigerant is performed. This
control can also compensate for tubing thermal loss by radiation during heating start as well as for oil recovery.
(1) Cooling control when the outdoor unit heat exchanger is acting as a condenser
Control time
Outdoor units
Electronic Thermostat
Indoor
units
*
Expansion Valve
RAP valve kit
Fan
When the above operation is finished, normal operation starts at the horsepower determined by the indoor units where
thermostats are ON.
60 seconds
All outdoor units operate at the maximum horsepower.
Valves at all indoor units operate at a fixed pulse according to the indoor unit capacity.
Valve kits at all indoor units operate in Cooling mode (OFF status).
Fan operates at the set fan speed or stops, depending on the indoor unit operation
mode.
1
(2) Heating control when outdoor unit heat exchanger is acting as an evaporator
Control time
Outdoor units
Electronic Thermostat
Expansion Valve
Indoor
units
*
When the above operation is finished, normal operation starts at the horsepower determined by the indoor units
where thermostats are ON
RAP valve kit
Fan
Minimum 1 min - Maximum 10 min [until max (pressure sensor temp., E1) 95°F ]
All outdoor units operate at the maximum horsepower.
Valves at all indoor units operate at 250 pulses as a default.
Valve kits at all indoor units operate in heating mode (ON status).
Fan operates at the set fan speed, stops or operates at a very low 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 heat-
ing operation.
4-2-2. Start of System Refrigerant Oil Recovery Control
When the oil level in an operating compressor is detected as 0 (zero), the compressor stops in 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 - 9
1
W-2WAY ECO-i SYSTEM
4. Special Controls
4-2-3. Refrigerant Oil Recovery Control between Systems
(1)
Simplified flow of system refrigerant oil recovery control
Refrigerant oil recovery control between systems shall be performed as the flow mentioned below.
Normal operation 3-minute stop Refrigerant oil recovery control between systems (Max. 3 minutes) 3-
minute stop Normal operation
(2)
Cooling cycle
Indoor
units
(3)
Heating cycle
Indoor
units
Control time
Outdoor units
Electronic Thermostat
Expansion Valve
RAP valve kit
Fan
Control time
Outdoor units
Electronic Thermostat
Expansion Valve
RAP valve kit
Fan
Maximum 3 minutes (Stops once before and once after control.)
All outdoor units operate at maximum horsepower.
Valves at all indoor units operate at a fixed pulse according to the indoor unit capacity.
Valve kits at all indoor units operate in Cooling mode (OFF status.)
Fan operates at the set fan speed, or stops depending on the operation mode of the
indoor unit.
Maximum 3 minutes (Stops once before and once after control.)
All outdoor units operate at maximum horsepower.
Valves at all indoor units operate at 480 pulse.
Valve kits at all indoor units operate in Heating mode (ON status.)
Fan operates at the set fan speed, stops or operates at a very low speed.
Control Functions
4-3. Defrost Control
4-3-1. Defrost Methods
This system uses the following 2 defrosting systems.
System employsDefrost control method
1 outdoor unit in the refrigerant system
2 outdoor units in the refrigerant system
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.
Reverse cycle defrost
Outdoor unit cycle defrost
1 - 10
W-2WAY ECO-i 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.
Control Functions
Heat exchange liquid temperature °F
–6.5
Defrosting operation
end temperatur
50
30
26
17
14
–9
–13
e
50
The frost detection area is
located under the thick lines
(The end temperature
is different from the
above detection
temperature.)
External temperature °F
L1
L2
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).
1
4-3-5. Reverse Cycle Defrost
If there is 1 outdoor unit and no thermal storage tank in a refrigerant system, a reverse cycle defrost will be carried out.
• Defrost flowE: Evaporator operation
C: Condenser operation
EC: Switching from evaporator operation to condenser operation
CE: Switching from condenser operation to evaporator operation
Outdoor unit status
Stopped indoor units
Indoor units where fan is operating
Cooling mode
indoor units
Heating mode
indoor units
Thermostat ON
Thermostat OFF
Thermostat ON
Thermostat OFF
Compressor
Time
Defrost preparation
E C
C E
C E
C E
C E
C E
C E
StoppedStopped
1 min
E C
E
E
E
E
E
E
Operating
1 min
Defrost in progress
C
E
E
E
E
E
E
Operating
1 - 11
Defrost
end
judgment
Max. 10 min
Defrost end
C E
E C
E C
E C
E C
E C
E C
1 min
1
W-2WAY ECO-i 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 con-
denser), 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.
Defrost sequence
(2)
Outdoor unit cycle defrost is always completed in 2 defrost operations.
(A) When there are 2 outdoor units
Switch
Defrost
outdoor unitoutdoor unit
Evaporator
Evaporator
outdoor unitoutdoor unit
Defrost
Control Functions
First operationSecond operation
• Defrost flowE: Evaporator operation
C: Condenser operation
S: Shut off
EC: Switching from evaporator operation to condenser operation
CE: Switching from condenser operation to evaporator operation
Outdoor unit(s) where defrost occurs first
Outdoor compressor(s) where defrost occurs first
Outdoor unit(s) where defrost follows later
Outdoor compressor(s) where defrost follows later
Stopped indoor unit(s)
Indoor units where fan is operating
Heating mode indoor
units
Thermostat ON
Thermostat OFF
Time
Defrost
preparation
E C
OFF
E
ON
S
S
C
C
1 min
Defrost in
progress
C
ON
E
Defrost
ONON
end
S
judgment
S
C
C
Switch
C E
OFF
E C
OFF
S
S
C
C
1 min
E
ON
C
SS
S
C
C
Defrost in
progress
Defrost
end
judgment
Defrost
preparation
E or S
OFF
C E or S
OFF
S
C
C
1 minMax. 6 minMax. 6 min
1 - 12
W-2WAY ECO-i 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 50°F or higher at all temperatures sensors installed on the outdoor unit heat
exchanger coils.
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
1 - 13
5. Other Controls
5-1. Oil Control
5-1-1. Oil level
W-2WAY ECO-i SYSTEM
Control Functions
1
Oil level
2
1
0
MeaningConditions of oilJudgement
Sufficient
Slightly low
Extremely low
The compressor contains oil more than
the oil level which is necessary and
sufficient for normal operation.
The compressor contains sufficient oil
but there is a possibility of shortage
against the required oil level.
The compressor oil is short against
the required oil level sufficient for normal
operation.
There is no problem.
Confirm that oil is returned after
performing the oil control operation.
Confirm that oil level is recovered to the
required level after performing the oil
recovery control between systems.
At the time immediately after the oil level changes from 2 to 1, there is a specified amount of oil in the compressor.
Namely, soon after the oil level is changed to 1, the oil in the compressor is not empty. If the oil level “0” indication
continues for more than 5 to 10 minutes, it seems short of oil in the system. Check for any oil leakage as well as the
refrigerant tubing.
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.
Operation when oil level is not 2.
(1)
30 seconds after the oil level changes from 2 to 1, the recovery valves turn ON.
However, if the oil level becomes 2, this control is stopped.
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 dose not become 2.
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 minus1) 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.
(B) Oil-supply outdoor unit
The balance valve turns ON and remains ON.
The bypass valve repeatedly turns ON and OFF according to a constant cycle.
5-1-5. Indoor unit refrigerant oil self-recovery control
Refer to the items concerned with indoor unit special control.
1 - 14
W-2WAY ECO-i 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.
The OFF conditions take priority over the ON conditions for this valve.
(1)
This valve is OFF when the outdoor unit is stopped.
(2)
This valve is ON when special control is in progress.
(3)
(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.
Hp
1
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 turned ON at the same time with 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 is ON during heating operation and when it turns ON for the purpose
of recovering refrigerant in the outdoor unit at the end of the heating operation.
After the valve turns from ON to OFF, it will not turn ON again for 15 minutes.
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 contin-
ues for a set length of time, and when liquid back-flow is judged to be occurring.
Lp
1 - 15
1
W-2WAY ECO-i SYSTEM
6. Operation of Solenoid Valves
Control Functions
6-3. 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
This valve turns ON when separator oil self-recovery control is in progress.
(A)
This valve is ON when unit refrigerant oil recovery control is in progress (oil-receiving unit).
(B)
This valve is ON when control the system in case of insufficient refrigerant gas.
(C)
This valve turns ON for 60 seconds after a constant-speed compressor starts.
(D)
This valve turns ON for 120 seconds after defrost control ends.
(E)
This valve turns ON for 10 seconds after the outdoor unit stops.
(F)
This valve remains OFF at all times other than (A) through (F) above.
(G)
6-4. 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.)
7-1. Types of Electronic Thermostatic Expansion Valves
[CHDX07263, CHDX09663]
Electronic
control valve
Capacity
Electronic
control valve 1
Electronic
control valve 2
Electronic
control valve 4
7296
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 Exchangers which are controlled by each Electronic Thermostatic Expansion Valve
The configuration of heat exchangers is as shown in the figure below. MOV3 is excluded.
1
Heat
Heat exchanger 2
Front
exchanger 1
Operation of Electronic Thermostatic Expansion Valve during normal unit operation
If any one compressor in the outdoor unit is operating, the outdoor heat exchanger coil is used.
In cooling operation, all the inverter compressors are designed to operate, therefore, all the outdoor heat
exchangers in the outdoor units will be used.
SH control controls the difference between the liquid temperature and gas temperature to 2°F ~ 10°F.
During heating mode SH operation in the heat exchanger 2 side, in order to prevent a liquid-back or high load
operation from occurring a control may be implemented so that refrigerant may not flow intentionally to the heat
exchanger.
During cooling operation, 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 refrigerant flow in the indoor unit will be reduced significantly. To prevent this trouble from occurring, MOV4 operates so as to increase supercooling in the double
tube coil near the outlet of the outdoor unit.
MOV4 controls refrigerant so that it will not flow back to the compressor in the liquid state with a suction temperature sensor near the accumulator and a low pressure sensor.
Gas refrigerant returns
to the accumulator.
)
Liquid refrigerant (SC = 0°F)
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 thermostatic expansion valve opens to
480 pulses to cool down the compressor. This operation takes priority over operation intended to increase SC.
It is performed at top priority in all operating modes. In addition, the valve opening adjustment will be made
when the discharge temperature falls.
Liquid refrigerant returns
to the accumulator.
Does not fully evaporate,
resulting in liquid back-up.
Liquid refrigerant
Liquid refrigerant
Electronic control valve
4 opens to 480 pulses.
1 - 18
W-2WAY ECO-i 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
Cooling operation
Heating operation
*
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
Outdoor air temp.
1
<
59°F: 0
°F
: 1
Max. fan mode
14
14
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, say for about 2 hp, the initial mode may be recalculated and
may be again fixed for 30 seconds.
1
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) When all indoor units are operating in cooling mode
(A) Fan mode is increased when the high pressure satulation temperature sensed by the pressure sensor is
high, and is decreased when the pressure sensor temperature is low.
* The fan mode is always increased when the high pressure satulation temperature sensed by the pressure
sensor is 113°F or higher.
The fan mode may be decreased when symptoms of insufficient refrigerant gas are detected at an indoor unit.
(B)
(2) When all indoor units are operating in heating mode
If the condensation temperature is low, the fan mode is increased at regular intervals.
(A)
If the condensation temperature is high, the fan mode is decreased in order to prevent excessive loads.
(B)
The fan mode may be increased when the outdoor liquid temperature drops to 44°F or below.
(C)
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.
1 - 19
W-2WAY ECO-i SYSTEM
9. Demand Control
Serial-parallel I/O must be connected in order to perform demand control. The below input is received by serialparallel 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
1
Demand setting
Contact 1
Input present
:
Contact 2
Control
No control
Operates to the upper limit for the rated current.
Operates to 70% of the upper limit for the rated current.
Always in stop condition.
Input not present
:
Demand meaning
Operates to maximum capacity.
-
-
-
* The rated current indicates the current value that is listed in the catalog or similar material.
1 - 20
W-2WAY ECO-i SYSTEM
10. Indoor Unit Control of the Electronic Control Valve
Control Functions
10-1. Normal Control
(1) Cooling operation
Position of electronic control valve
Outdoor unit operating
Cooling
Stopped
Fan
Thermostat
Thermostat
OFF
ON
Performs SH control in the range of 55 – 480
pulses.
2020
2020
2020
* The SH target value is controlled so that the E3 - E1 becomes between 2°F to 6°F, depending on the operating
conditions.
However, a decline in the required level may cause the SH target value to increase. Be aware that in this case, the
electronic control valve closes slightly. This can be easily identified incorrectly as insufficient gas.
(2) Heating operation
(A) Except Type D
Position of electronic control valve
Outdoor unit operating
Liquid refrigerant is gradually returned to the outdoor unit
at pulses ranging from 55 to 80.
Liquid refrigerant is gradually returned to the outdoor unit
at pulses ranging from 55 to 80.
Liquid refrigerant is gradually returned to the outdoor unit
at pulses ranging from 55 to 80.
Performs SC distribution control within the range of 55–
480 pulses.
Heating
Stopped
Fan
Thermostat
OFF
Thermostat
ON
Outdoor unit
stopped
–
Outdoor unit
stopped
85
85
85
–
1
* The SC target value is controlled so that the high pressure saturated temp. - E1 becomes between 10°F to
40°F , depending on the operating conditions.
(B) Type D
Position of electronic control valve
Outdoor unit
stopped
–
Heating
Outdoor unit operating
Stopped
Fan
Thermostat
OFF
ThermostatONPerforms SC distribution control within the range of 55 –
480 pulses.
2020
2020
2020
* The SC target value is controlled so that the high pressure saturated temp. - E1 becomes between 10°F to
40°F, depending on the operating conditions.
However, if installation is combined with except Type D, the high pressure saturated temp. - E1 may be
controlled between 10°F to 80°F.
1 - 21
10. Indoor Unit Control of the Electronic Control Valve
10-2. Special Control
W-2WAY ECO-i SYSTEM
Control Functions
1
Control
4-way valve
adjustment control
Reverse cycle
defrost control
Outdoor cycle
defrost control
System refrigerant
oil recovery control
Operating
mode
Cooling
Heating
Heating
Cooling/
heating
Cooling
Heating
Subject indoor unitsPosition of electronic control valve
All indoor units
All indoor units
Stopped
Fan
Thermostat
ON
Thermostat
Heating
Heating
OFF
Stopped
Fan
Thermostat
ON
Thermostat
OFF
All indoor units
All indoor units
Fixed pulse for cooling, according to indoor unit
capacity
250
Cooling control, according to indoor unit capacity
Cooling control, according to indoor unit capacity
Fixed pulse for heating, according to indoor unit
capacity
Heating control, according to indoor unit capacity
However, position is 20 pulses for Type D.
60 pulses
60 pulses
60 pulses
60 pulses
Fixed pulse for cooling, according to indoor unit
capacity
250
1 - 22
W-2WAY ECO-i SYSTEM
11. Rap Valve Kit Control
A gas tube valve kit may be connected to the Type D indoor unit. When the gas tube valve kit is connected,
operations of gas tube valve kit and indoor unit electronic thermostatic expansion valve are as shown in the
table.
Control Functions
Stopped
Thermostat
Thermostat
CoolingHeating
Thermostat
Thermostat
Fan
ON
OFF
ON
OFF
Gas tube valve
OFF
OFF
ON
ON
OFF
OFF
Electronic thermostatic
expansion valve
20 pulses
20 pulses
20 pulses
Superheat control (65 – 480)
20 pulses
Superheat control (50 – 480)
1
1 - 23
1
W-2WAY ECO-i SYSTEM
12. Indoor Unit Refrigerant Oil Self Recovery Control
This control is carried out regularly in cooling mode only.
(1)
During stopped, fan or thermostat OFF condition, indoor unit expansion valve is opened regularly for 1 to 2 minutes regularly (at an interval of once every 2 hours.)
(2)
During the thermostat ON, the indoor unit electronic thermostatic expansion valve is opened about 10 pulses
from the current status.
Control Functions
1 - 24
W-2WAY ECO-i SYSTEM
13. Discharge Temperature
Control Functions
<Alarm Information>
(1) Discharge temperature protection alarm
This device sets an upper limit discharge temperature of 222°F for all compressors. When the discharge temperature reaches 222°F, that compressor is stopped and restarted. If the same high discharge condition occurs
4 times, then an alarm occurs.
After a compressor has stopped, that compressor will not operate until the temperature has dropped to or
below the start-prohibit temperature.
Discharge temperature protection list
Compressor No.Compressor 1Compressor 2
TypeInverterConstant-speed
Stop temp.
Start-prohibit temp.
Alarm display
(2) Discharge sensor trouble detection control
An alarm occurs if the discharge temperature remains abnormally high (above 158°F), when the system has
been stopped for 60 minutes.
* In this case, possible causes include sensor failure and compressor overheating caused by an insufficient
level of refrigerant.
The alarm also occurs if the sensor temperature is at or above the abnormal temperature (176°F) when 20 min utes have passed after the compressor stopped.
* In this case, it is possible that the discharge temperature from a different outdoor unit is being detected, due
to an error in the installation of the discharge thermistor.
222°F222°F
158°F158°F
P03P17
1
Discharge sensor failure list
Compressor No.Compressor 1Compressor 2
Type
Alarm display
InverterConstant-speed
F04F05
1 - 25
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