AHU Controller Specifications
1. Application
This controller is used to set up a system by connecting a field-supplied Air Handling Unit (AHU) to Mitsubishi
Electric City Multi outdoor unit. This controller can be used to control the system only in cooling mode.
Applicable models: PAC-AH63, 125, 140, and 250M-G
2. System restrictions and use of range
(1) System configuration
Connectable outdoor units PUY-P250,300,350YGM-A
PUHY-P250,300,350,400,450,500YGM-A
Refrigerant type R410A
Capacity of connectable indoor units 50~100% of outdoor unit capacity
Capacity ratio between AHU and STD
(standard indoor units manufactured by
Mitsubishi) in a system with one outdoor
units to which both indoor units and AHU
controllers are connected
Number of connectable indoor units P250, 1~12; P300, 1~15; P350, 1~18
* When an AHU is grouped with the standard indoor units in a system with one outdoor unit, the
capacity of the standard indoor unit may drop depending on the operating conditions of the AHU.
A system with one AHU is recommended.
(2) Operating conditions
Operating conditions of indoor, outdoor, air handling units (cooling/heating)
Unit Type Cooling Heating
AHU (evaporator inlet air temperature) 15~24ºCWB NOT available
Outdoor unit -5~43ºCDB -20~15.5ºCWB
STD in a system with one outdoor unit to
which both indoor units and AHU
controllers are connected
* While the AHU is running in cooling mode, the operation mode of the standard indoor units cannot be
changed to heating mode, as AHU is cooling only. The operation mode of the AHU cannot be changed to
cooling mode while the other units are running in heating mode. Stop all the units in the system to change
the operation mode.
If the units are operated beyond the conditions shown above, the units may make an error stop, and in
the worst case the compressor may not function properly. To avoid this, operate the units under the
conditions shown above.
(3) Refrigerant pipe size, pipe length, and height difference restrictions
Pipe size
(Liquid / Gas)
AH63,125,140 Φ9.52 / Φ15.88
AH200 Φ9.52 / Φ19.05
Capacity of connectable AHU in a system with one outdoor units
to which both indoor units and AHU controllers are connected
must be 50% or less of outdoor unit capacity
<Example>
AHU:STD = 50%:50% Acceptable
= 70%:30% Not acceptable
= 30%:70% Acceptable
=100% : 0% Acceptable
(when only AHU is connected)
P400, 1~20; P450, 1~22; P500, 1~25
15~24
ºCWB 15~27ºCDB
AH250 Φ9.52 / Φ22.2
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Pipe length
Height difference
(1) No further branching in the pipes is possible after the header branch.
(2) When cooling operation is performed when the outdoor temp. is 0
lower：H’=4m or less
(3) Equivalent pipes length(m)：Actual pipe length + A×number of bent.
Table A
Outdoor unit model A Outdoor unit model A
P250 0.42 P400 0.50
P300 0.42 P450 0.50
P350 0.47 P500 0.50
ºC or
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Amount of
refrigerant to be
added
(1) Original charge of refrigerant and the maximum total charge.
At factory shipment, refrigerant are charged in the outdoor unit as shown at
following Table. When extending the piping in the field, additional charge of
refrigerant is needed. Yet, the maximum total charge in the air conditioner
system should not be exceeded. The maximum additional charge varies on
models, shown as at following Table.
Ta b l e
PU(H)Y-YGM P250,300,350 P400 P450,500
Original charge A(kg) 9.5 13.0 22.0
Maximum total
charge
Maximum
additional
charge
B(kg) 40.0 40.0 67.0
C(kg) 30.5 27.0 45.0
(2) Calculate the additional charge for the air conditioner system in the field.
The additional charge (F kg) is calculated as follows. F should be round up to
0.1 digital, like 10.52→10.6kg.Yet, if F results bigger than C, the additional
charge is the maximum additional charge C.
F(kg)=(0.2×Ld)+ (0.12×Le)+ (0.06×Lf)+ (0.024×Lg)+D
Where Ld(m) : Length of liquid pipe sized Φ15.88
Le(m) : Length of liquid pipe sized Φ12.7
Lf(m) : Length of liquid pipe sized Φ9.52
Lg(m) : Length of liquid pipe sized Φ6.35
D(kg) : Additional charge of refrigerant required by the total capacity
of indoor units in the refrigerant system.
Total capacity of indoor
units connected
D(kg) 1.5 2.0 2.5 3.0
~161 161~330 331~480 481~500
3.
Product configuration
(1) Series configuration
Several types of controllers to accommodate different AHU capacities are available.
Select the appropriate controller.
Model name PAC-AH63M-G PAC-AH125M-G PAC-AH140M-G PAC-AH250M-G
Max. capacity (kW)
Min. capacity (kW)
Reference air
flow rate (m
Unit size
3
7.1 8.0 9.0 11.2 14.0 16.0 22.4 28.0
5.6 7.1 8.0 9.0 11.2 14.0 16.0 22.4
1250
/h)
1500 1750
2000 2500 3000 4000 5000
63 71 80 100 125 140 200 250
* Calculate the capacity of connectable indoor units using the “Unit size” in the table above.
The Unit size is set to the model name at factory shipment. Change the Unit size to the appropriate value
for the selected controller using the switch on the controller board. Refer to the installation manual for
how to change the Unit size.
(2) Controller components
Name Usage
Controller board For operation control Controller
Transformer For controller board
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LEV-kit
Thermistor
Clip
Insulation
Tie band
Tube
Installation manual
(3) Major specifications
Power supply 220~240V 50Hz
External dimension (mm) 382(430)×326×117(132)
Net weight (kg) 7
External finish(Munsel No.) 5Y 8/1
IP-class IP24
Remote controller temperature setting range
Operation
Temperature control
Terminal block For power source, for external I/O, for internal and external
communication, for remote controller, and for thermistor
Connector For remote controller and for level input switch
Relay For operation display and for error display
Electronic linear expan. valve
For detection of suction air temperature, liquid pipe
temperature, and gas pipe temperature
For mounting suction temperature thermistor
For insulating liquid pipe and gas pipe thermistor
For fixing liquid pipe and gas pipe thermistor
For fixing wiring
-
The figure in ( ) indicates mounting's.
14~30ºC
Operation by
optional remote
Press ON/OFF button on the remote controller to start/stop the
operation.
controller
Operation by
external input*
Connect the field-installed external thermostat (ON/OFF) to the
external input (ON/OFF) to start the operation when the
external thermo is ON, and stop the operation when it is OFF.
Interlock
operation with
AHU fan
Interlock setting between the error stop of AHU fan and the
external input ON/OFF must be made to close the LEV of AHU
heat exchanger when AHU fan makes an error stop. Refer to
section 5 for details.
Temperature
control by
optional remote
The thermostat will be turned off (LEV will be closed) when the
suction air temperature thermistor reading reaches the preset
temperature on the remote controller.
controller
Temperature
control by
external
thermostat
Connect the field-installed external thermostat (ON/OFF) to the
external input (ON/OFF) to start the operation when the
external thermo is ON, and stop the operation when it is OFF.
The thermostat will be turned off when the suction air
temperature thermistor reading reaches the preset temperature
on the remote controller. Refer to section 5 for details.
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Protection function
Freeze
prevention
After 16-minute or more cooling operation, and when 1ºC or
less of the thermistor detection temperature for liquid pipe is
detected for 3 minutes in a row, the linear expansion valve will
be closed to prevent freezing. The operation will be normal
when either of the following conditions is met.
- When 3 minutes have passed after 10
ºC or more of the
thermistor detection temperature for liquid pipe is
detected.
- When 6 minutes have passed after the expansion valve
was closed to prevent freezing.
Sensor failure If a short or an open of the thermistor is detected during
operation, the error will affect the LEV, and it will be closed.
Communication
error
If the addresses overlap or the transmission line is not
connected properly, the error will affect the LEV, and it will be
closed.
Other types of
error
If the outdoor unit in the system with one outdoor unit has a
problem, the problem will affect the entire system, and the
compressor will stop.
* Default setting (operation mode setting or temperature setting) with an optional remote controller must be
made when an external input is used.
4. Requirements on AHU design
(1) Design method of heat exchanger
Model name
Unit size
Max. capacity (kW)
Min. capacity (kW)
Reference air flow
3
/h)
rate (m
Heat exchanger tube
size in evaporator
Min. volume inside
heat exchanger tube
Max. volume inside
heat exchanger tube
Standard number of paths
LEV inlet temperature
Evaporating temperature
SH
Evaporator outlet
temperature
Evaporator suction
air temperature
PAC-AH63M-G PAC-AH125M-G PAC-AH140M-G PAC-AH250M-G
63 71 80 100 125 140 200 250
7.1 8.0 9.0 11.2 14.0 16.0 22.4 28.0
5.6 7.1 8.0 9.0 11.2 14.0 16.0 22.4
1250
1500 1750
2000 2500 3000 4000 5000
Φ9.52
950
1800
3
25ºC
8.5ºC
5K
13.5ºC
27ºCDB/19ºCWB
1100 1200
2000 2250
3 3
1500 1900 2150 3000 3750
2850 3550 4050 5700 7100
4~5 4~5 5~6 6~10 8~10
Calculate the capacity of connectable indoor units using the “Unit size” in the table above.
(2) Heat exchanger manufacturing
Design pressure 4.15 MPa
Evaporator burst pressure
Compressive strength
The compressive strength of the evaporator and of other pipes must exceed
12.45MPa.
Insufficient withstand pressure may cause the pipes to crack and result in gas
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leakage.
Contamination control Wash the heat exchanger with detergent to make the allowable level of
contamination per unit length of the heat exchanger tube the following values or
less on the assumption that the heat exchanger tube size is
chlorinated detergent. Do not leave flux.
Allowable level of contamination may cause the compressor not to function
properly. Contamination amount: residual water amount 0.6 mg/m or less,
residual oil amount 0.5 mg/m or less, amount of solid contaminants 1.8 mg/m or
less
(3) Installation conditions of AHU controller
Installation
site
- Avoid locations in direct sunlight.
- Avoid locations exposed to steam or oil vapor.
- Avoid locations where combustible gas may leak, settle or be generated
- Avoid installation near machines emitting high-frequency waves.
- Avoid places where acidic solutions are frequency waves.
- Avoid places where sulfur-based or other sprays are frequently used.
- Avoid places where vibration may occur.
Ambient
temperature
Ambient
Relative humidity of 95% or less (No dew condensation is allowed)
humidity
Installation
angle
(4) Cautions on installing LEV-kit
Installation environment
Installation angle Install the motor above the horizontal.
Pipe size
Caution on brazing LEV can withstand only up to 120ºC. Cool the LEV while brazing.
Wire connection - Connect the wire according to the wire color code to avoid miswiring. In case
Avoid locations in direct sunlight.
Φ9.52 (Brazing)
Use two LEVs when installing AH250. Connect two LEVs in parallel, and
connect them to the appropriate refrigerant pipe according to the unit size.
-
- Be careful with the plate edge not to damage to the wire from being damaged.
- The wire can withstand only up to 105ºC. Keep the wire away from
- Bend the wire into "U" shape to prevent water from running down the wire and
(5) Cautions on installing thermistor
Installation site - Install the pipe thermistor properly so that it can accurately measure the pipe
- Install the liquid thermistor sensor at the evaporator inlet where the lowest
- Install the gas pipe thermistor at the junction at the evaporator outlet.
- Install the suction air temperature thermistor at a place where the average
Wire connection - Connect the wire according to the terminal number to avoid miswiring.
Φ9.52. Do not use
-20~43
ºC
Vertical installation
of AH250, connect two wires to the same terminal.
Do not strain the power supply wires.
high-temperature part.
from dripping on the electrical components or the LEV.
temperature. Protect it with the insulation material so that it is not affected by
the temperature at other places.
temperature is found, as the thermistor is used for freeze prevention.
temperature of suction air into the evaporator can be measured.
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(6) Other cautions
- The refrigerant temperature inside the evaporator may become 0
AHU main body or on the refrigerant pipe may occur.
- Drain the AHU properly.
If the LEV of AHU does not close due to malfunction in a system with one outdoor unit to which both
indoor units and AHU controllers are connected and if the AHU is stopped and other STD are in
operation, the
temperature of AHU evaporator becomes low and dew may condense on the AHU main body.
Take appropriate measures against dew condensation to avoid serious damage to the unit.
- When a heater for heating operation is built-in and when both the heater for heating operation
and the evaporator are operated, the operation must be conducted within the evaporator inlet
temperature range.
- Install an air filter on the evaporator.
- Interlock the unit with the fan to prevent the refrigerant system from running when the fan is stopped.
- In a system with one outdoor unit to which both in indoor units and AHU controllers are connected,
the LEV of AHU will be slightly open in heating operation to prevent the refrigerant from
accumulating inside the AHU heat exchanger, and the temperature of theAHU heat exchanger will
slightly rise.
- In a system with one outdoor unit to which both indoor units and AHU controllers are connected, the
LEV will be temporarily open in heating operation to run the outdoor unit in defrost operation. In this
case, low-temperature refrigerant will run inside the AHU heat exchanger, and the heating capacity
of AHU that is running heating operation using the heater for heating operation will temporarily drop.
- Capacity control is affected by the outdoor temperature. When the outdoor temperature drops, the
discharge temperature also drops. Take proper measures to control the room temperature, to select
the outlet position, and to prevent dew condensation.
5.
Requirements on interface with controller
Item Connection circuit
Operation
■Operation contact specifications
■Use a relay when the electrical wire exceeds 10m.
- Do not strain the power supply wires.
- Be careful with the plate edge not to damage to the wire from being damaged.
- The wire can withstand only up to 105ºC. Keep the wire away from
high-temperature part.
- Bend the wire into "U" shape to prevent water from running down the wire and
from dripping on the electrical components or the thermistor.
ºC. Note that dew condensation on
SW1: Operation command
(field supply)
Minimum applicable load
DC5V, 1mA
X: Relay(field supply)
Minimum applicable load
DC5V, 1mA
SW2: Operation command
(field supply)
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■Interlock operation with fan error and connection example of field-installed thermostat
Interlock the unit so that the unit stops when an error occurs on the fan (field supply).
Operation signal
Error signal
Electrical wiring
X: Relay
(field supply)
Minimum applicable load
DC5V, 1mA
SW2: Operation command
(field supply)
Error: Error of fan sections
(field supply)
Thermo: Thermistor
(field supply)
L1: Operation display lamp
(field supply)
Display power source:
DC30V 1A, AC100V/200V 1A
L2: Error display lamp
(field supply)
Display power source:
If error resets (stop operation) and restart operations are repeatedly performed, the
Compressor may be damaged seriously. Install an error lamp, and contact the service
firm or the dealer when an error occurs. Installation of the remote controller is
recommended so that the error details can be checked.
DC30V 1A, AC100V/200V 1A
- Power supply cords of appliances shall not be lighter than design 245 IEC 57 or 227
IEC 57.
- A switch with at least 3mm contact separation in each pole shall be provided by the Air
conditioner installation.
- The diameter of the power supply wire to the AHU controller must be 1.5mm
- Use an earth leakage breaker with a sensitivity of 30 mA 0.1s or less.
- Use a separate wire for AHU’s main circuit from that for the circuit shown above. Select
the appropriate wire or the protection device on site, according to the AHU
specifications.
Transmission cables - Type of cable : Shielding wire (2-core) CVVS or CPEVS or MVVS
- Cable diameter : 1.25mm
M-NET Remote controller
cables
MA Remote controller
cables
- Type of cable : Sheathed wire 2-core cable(unshielded) CVV
- Cable diameter: 0.3~1.25mm
(0.75~1.25mm
* When 10m is exceeded, use cables with the same specification as transmission cables.
- Type of cable : Sheathed wire 2-core cable(unshielded) CVV
- Cable diameter: 0.3~1.25mm
(0.75~1.25mm
- Max length : 200m
2
2
2
: connected with simple remote controller)
2
2
: connected with simple remote controller)
2
or larger.
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CVVS, MVVS : PVC insulated PVC jacketed shielded control cable
CPEVS : PE insulated PVC jacketed shielded communication cable
CVV : PV insulated PVC sheathed control cable
6. Related cautions
(1) Installation work
- Secure enough service space for replacement of the LEV and the thermistor.
- After an AHU controller is installed, address setting and unit size setting on the switch on the
controller board are necessary. Refer to the installation manual for the setting method.
- Refer to the outdoor unit installation manual or the data book for installation of the outdoor unit.
(2) Test run
- Turn on the main power to the unit at least 12 hours before test run to power the crankcase heater.
Insufficient powering time may result in compressor damage.
- As the temperature setting and the operation mode setting are made at initial setting, a remote
controller is necessary. Remove the remote controller after making the initial settings if it is used.
In case of PAR21MAA, remove the remote controller after turning off the power of the indoor and
outdoor units. In case of PAR-27MEA, remove it after deleting the address of the remote
controller.
(Refer to the installation manual for remote controller for more details.)
(3) Operation control
- Remove the connector inside the AHU controller when a local remote controller is used. When the
connector is connected, the controller will be in the remote operation mode, and the operation by the
local remote controller will be prohibited.
- If the error lamp lights or the error display appears on the remote controller, do not make an error
reset by yourself. Contact the service firm or the dealer.
- Refer to the data book for system controller when using the system controller.
(4) Service
- Establish a regular maintenance routine to prolong the life of the units. It is recommended that the
maintenance contract be concluded with a maintenance firm.
7.
Warranty
- Specifications of AHU and compatibility with regulations must be confirmed by your company.
- Selection of an appropriate AHU (with appropriate specifications to match those of units connected
to the AHU such as configuration, dimension, lifetime, vibration, noise, or characteristic) must be
made by your company.
- Mitsubishi Electric shall not be liable for any damage to the entire system or the AHU main body
caused by connected AHU with wrong specification or wrong usage of AHU.
- Mitsubishi Electric shall not be liable for any damage to the outdoor units or the indoor units
connected caused by AHU damage.
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EE
External Dimension
PAC-AH63/125/140/250M-G
R3.5
R7.5
Φ7.0
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Electrical Wiring Diagram
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