Mitsubishi WYNC0-8494 Technical Guide

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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