Mitsubishi WYNC0-8940 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.

Applicable models: PAC-AH125, 140, and 250M-H

2. System restrictions and use of range

(1) System configuration

Connectable outdoor units PUHY-P250,300,350,400,450,500YGM-A

Refrigerant type R410A

Capacity of connectable AHU units 80~100% of outdoor unit capacity

Connectable indoor units Do not group the AHU with the standard indoor unit.

(2) Operating conditions

Operating conditions of indoor, outdoor, air handling units (cooling/heating)

Unit Type Cooling Heating

AHU (Heat exchanger inlet air temperature) 15~24ºCWB

Outdoor unit -5~43ºCDB -20~15.5ºCWB

(3) Refrigerant pipe size, pipe length, and height difference restrictions

Model names Unit capacity Pipe size(Liquid / Gas)

-10~15℃DB

PAC-AH125M-H
PAC-AH140M-H

100, 125, 140 Φ9.52 / Φ15.88

200 Φ9.52 / Φ19.05 PAC-AH250M-H

250 Φ9.52 / Φ22.2

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Pipe length
Height difference

(a) No further branching in the pipes is possible after the header branch.
(b) Cooling operation is performed when the outdoor temp. is 0

ºC or lower：

H’=4m or less

(c) 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

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Amount of
refrigerant to be
added

(a) 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 the 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

(b) Calculation of 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 maximum
additional charge is 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 AHU units in the refrigerant system.

Total capacity of AHU
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-AH125M-H PAC-AH140M-H PAC-AH250M-H

Cooling

Heating

Reference air

flow rate (m

Unit capacity

Max. capacity (kW)

Min. capacity (kW)

Max. capacity (kW)

Min. capacity (kW)

3

/h)

11.2 14.0 16.0 22.4 28.0

9.0 11.2 14.0 16.0 22.4

12.5 16.0 18.0 25.0 31.5

10.0 12.5 16.0 18.0 25.0

2500 3000 4000 5000

2000

100 125 140 200 250

* Calculate the capacity of connectable indoor units using the “Unit capacity” in the table above.

The Unit capacity is set at the model name at factory shipment. Change the Unit capacity to the
appropriate value for the selected controller using the switch on the controller board. When it is needed,
refer to the installation manual for how to change the Unit capacity.

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(2) Controller components

Name Usage

Controller

Controller board For operation control

Transformer For controller board

Terminal block For power source, for external I/O, for internal and external

Connector For remote controller and for level input switch

Relay For operation display and for error display

LEV-kit

Thermistor

Clip

Insulation

Tie band

Tube

Installation manual

(3) Major specifications

Power supply 208~240V 50/60Hz

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

Cooling

Heating

Operation by
optional remote
controller

Operation by
external input*

Interlock
operation with
AHU fan

Temperature
control by
optional remote
controller

communication, for remote controller, and for thermistor

Electronic linear expan. valve

For detection of suction air temperature, discharge temperature,
liquid pipe temperature, and gas pipe temperature

For mounting suction air and discharge air 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

17~28ºC

Press ON/OFF button on the remote controller to start/stop the
operation.

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 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.

Discharge air temperature control or suction/room air temperature

control can be chosen by changing the switch on control board
and by changing the position of attached thermistor.

In controlling the discharge air temperature, the capacity is
controlled so that detection temperature of the thermistor installed
in an outlet of AHU reaches the set temperature by remote
controller.
In controlling the suction/room air temperature, the capacity is
controlled so that thermostat becomes OFF if detection
temperature of the thermistor installed in an inlet of AHU or the
room reaches the set temperature by remote controller.

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Temperature
control

Temperature
control by
optional remote
controller

(i)Thermostat condition in controlling the discharge air
temperature

TH21:Discharge air temperature
TH24:Suction air temperature
To : The preset temperature on the remote controller
*The value shown with a square in the table below can be changed by
a dip-switch.

Cooling
The range of
“To”

Thermostat
OFF
a) or b) or c)
Thermostat
ON
a) & b) & c)
& d)

Heating
The range of
“To”

Thermostat
OFF
a) or b) or c)
Thermostat
ON
a) & b) & c)
& d)

14～30℃

a) TH24<To
b) TH24<14℃
c) TH21<To – 2℃ is continued for 10 minutes.
a) TH24 > To +1℃
b) TH24 > 15℃
c) TH21 > To +1℃
d) It passes from thermostat OFF for 3 minutes.

17～28℃

a) TH24>To
b) TH24>15℃
c) TH21>To + 3℃ is continued for 10 minutes.
a) TH24 < To –1℃
b) TH24 < 14℃
c) TH21 < To –1℃
d) It passes from thermostat OFF for 3 minutes.

(ii)Thermostat condition in controlling the suction/return air
temperature

TH21:Suction/Return air temperature
TH24:Suction air temperature
To : The preset temperature on the remote controller
*The value shown with a square in the table below can be changed by a
dip-switch.
Cooling
The range of
“To”

Thermostat
OFF
a) or b)
Thermostat
ON
a) & b) & c)

Heating
The range of
“To”

Thermostat
OFF

14～30℃

a) TH24<20℃
b) TH21<To-0.5℃

a) TH24 > 21℃
b) TH21 > To +0.5℃
c) It passes from thermostat OFF for 3 minutes.

17～28℃

a) TH24>21℃
b) TH21>To

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