Mitsubishi PWFY-P36NMU-E-BU How to use

4th edition
Service Handbook PWFY-P36NMU-E-BU / PWFY-P36, P72NMU-E(2)-AU
HWE0903C
New publication effective Aug. 2015
Specifications subject to change without notice
2015
Service Handbook
PWFY-P36NMU-E-BU
PWFY-P36, P72NMU-E-AU
PWFY-P36, P72NMU-E2-AU
Model
Service Handbook
PWFY-P36NMU-E-BU
PWFY-P36, P72NMU-E-AU
PWFY-P36, P72NMU-E2-AU
Model
www.MitsubishiElectric.com

Contents
1Read Before Servicing ................................................................ 7
[1] Items to Be Checked .............................................................. 7
[2] Necessary Tools and Materials .............................................. 8
[3] Piping Materials ...................................................................... 9
[4] Storage of Piping .................................................................... 11
[5] Piping Processing .................................................................. 11
[6] Brazing.................................................................................... 12
[7] Air Tightness Test .................................................................... 13
[8] Vacuum Drying (Evacuation) .................................................. 14
[9] Refrigerant Charging .............................................................. 15
[ 10 ] Remedies to be taken in case of a Refrigerant Leak ............ 15
[ 11 ] Characteristics of the Conventional and the New Refrigerants .. 16
[ 12 ] Notes on Refrigerating Machine Oil........................................ 17
2Restrictions .................................................................................. 18
[1] Types and Maximum allowable Length of Cables .................. 18
[2] Types of Switch Setting and Address Setting ........................ 19
[3] Examples of system connection ............................................ 20
[4] Restrictions on piping length .................................................. 21
3Components of the Unit .............................................................. 22
[1] Appearance of the Components and Refrigerant Circuit........ 22
[2] Control Box ............................................................................ 23
[3] Circuit Board .......................................................................... 25
4Remote Controller ........................................................................ 28
[1] Functions and Specifications of MA Remote Controller .................. 28
[2] Interlocking Setting via the MA Remote Controller ........................ 29
5Electrical Wiring Diagram ............................................................ 31
[1] PWFY-P36NMU-E-BU ............................................................ 31
[2] PWFY-P36, P72NMU-E/E2-AU .............................................. 32
6Refrigerant Circuit ........................................................................ 34
[1] Refrigerant Circuit Diagram .................................................... 34
[2] Pump interlock ........................................................................ 35
[3] Functions of Principal Parts.................................................... 36
7Control.......................................................................................... 38
[1] Dip Switch Functions and Their Factory Settings .................. 38
8Test Run ...................................................................................... 41
[1] Check Items before Test Run.................................................. 41
[2] Test Run Method .................................................................... 41
[3] Refrigerant .............................................................................. 41
[4] Symptoms that do not Signify Problems ................................ 42
[5] Standard operation data ........................................................ 42
9Troubleshooting ............................................................................ 43
[1] Check Code List .................................................................... 43
[2] Responding to Error Display on the Remote Controller ........ 44
[3] Troubleshooting Principal Parts .............................................. 60
[4] Maintenance .......................................................................... 74
0LED display .................................................................................. 79
[1] LED Monitor Display .............................................................. 79
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Safety Precautions.qx 7/24/15 1:24 PM Page 2

Safety Precautions
Before installing the unit, thoroughly read the following safety precautions.
Observe these safety precautions for your safety.
WARNING
This symbol is intended to alert the user to the presence of important instructions that must be followed to avoid
the risk of serious injury or death.
CAUTION
This symbol is intended to alert the user to the presence of important instructions that must be followed to avoid
the risk of serious injury or damage to the unit.
After reading this manual, give it to the user to retain for future reference.
Keep this manual for easy reference. When the unit is moved or repaired, give this manual to those who provide these
services.
When the user changes, make sure that the new user receives this manual.
WARNING
Ask your dealer or a qualified technician to install the
unit.
Improper installation by the user may result in water leak-
age, electric shock, smoke, and/or fire.
Do not use steel pipes as water pipes.
Copper pipes are recommended.
The water circuit should be a closed circuit.
Properly install the unit on a surface that can with-
stand the weight of the unit.
Unit installed on an unstable surface may fall and cause in-
jury.
Only use specified cables. Securely connect each ca-
ble so that the terminals do not carry the weight of the
cable.
Improperly connected or fixed cables may produce heat
and start a fire.
Take appropriate safety measures against strong
winds and earthquakes to prevent the unit from falling.
If the unit is not installed properly, the unit may fall and
cause serious injury to the person or damage to the unit.
Do not make any modifications or alterations to the
unit. Consult your dealer for repair.
Improper repair may result in water leakage, electric shock,
smoke, and/or fire.
In the event of a refrigerant leak, thoroughly ventilate
the room.
If refrigerant gas leaks and comes in contact with an open
flame, poisonous gases will be produced.
Do not touch the refrigerant pipes and Water
pipes.
Improper handling may result in injury.
Properly install the unit according to the instructions
in the installation manual.
Improper installation may result in water leakage, electric
shock, smoke, and/or fire.
Have all electrical work performed by an authorized
electrician according to the local regulations and in-
structions in this manual, and a dedicated circuit must
be used.
Insufficient capacity of the power supply circuit or improper
installation may result in malfunctions of the unit, electric
shock, smoke, and/or fire.
Do not use refrigerant other than the type indicated in the
manuals provided with the unit and on the nameplate.
Doing so may cause the unit or pipes to burst, or result in
explosion or fire during use, during repair, or at the time of
disposal of the unit.
It may also be in violation of applicable laws.
MITSUBISHI ELECTRIC CORPORATION cannot be held
responsible for malfunctions or accidents resulting from the
use of the wrong type of refrigerant.
Before performing maintenance work, turn off the
power to both indoor and outdoor units.
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Safety Precautions.qx 7/24/15 1:24 PM Page 1

WARNING
Securely attach the terminal block cover (panel) to the
unit.
If the terminal block cover (panel) is not installed properly,
dust and/or water may infiltrate and pose a risk of electric
shock, smoke, and/or fire.
Only use the type of refrigerant that is indicated on the
unit when installing or reinstalling the unit.
Infiltration of any other type of refrigerant or air into the unit
may adversely affect the refrigerant cycle and may cause
the pipes to burst or explode.
When installing the unit in a small room, exercise cau-
tion and take measures against leaked refrigerant
reaching the limiting concentration.
Consult your dealer with any questions regarding limiting
concentrations and for precautionary measures before in-
stalling the unit. Leaked refrigerant gas exceeding the lim-
iting concentration causes oxygen deficiency.
Consult your dealer or a specialist when moving or re-
installing the unit.
Improper installation may result in water leakage, electric
shock, and/or fire.
After completing the service work, check for a gas
leak.
If leaked refrigerant is exposed to a heat source, such as a
fan heater, stove, or electric grill, poisonous gases may be
produced.
Do not try to defeat the safety features of the unit.
Forced operation of the pressure switch or the temperature
switch by defeating the safety features of these devices, or
the use of accessories other than the ones that are recom-
mended by MITSUBISHI may result in smoke, fire, and/or
explosion.
Only use accessories recommended by MITSUBISHI.
Ask a qualified technician to install the unit. Improper instal-
lation by the user may result in water leakage, electric
shock, smoke, and/or fire.
Control box houses high-voltage parts.
When opening or closing the front panel of the control box,
do not let it come into contact with any of the internal com-
ponents. Before inspecting the inside of the control box,
turn off the power, keep the unit off for at least 10 minutes,
and confirm that the voltage between FT-P and FT-N on
INV Board has dropped to DC20V or less. (It takes about
10 minutes to discharge electricity after the power supply is
turned off.)
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