MITSUBISHI ELECTRIC PEFY-P54NMAU-E3 (01) PDF DOCUMENT

Before installation and performing electrical work, it is crucial to read and observe all safety precautions. Failure to follow instructions may result in serious injury, death, or damage to the unit.

WARNINGS:

• Only use the refrigerant type indicated in the manuals and on the nameplate. Using a different refrigerant may cause the unit or pipes to burst, or result in an explosion or fire.

• Installation should be performed by a dealer or a qualified technician. Improper installation by the user can lead to water leakage, electric shock, or fire.

• Install the unit on a surface that can withstand its weight. An unstable surface may cause the unit to fall, resulting in injury.

• Use only specified cables and connect them securely, ensuring terminals do not bear the cable’s weight. Improper connections can generate heat and cause a fire.

• Take appropriate safety measures against wind and earthquakes to prevent the unit from toppling over.

• Only use accessories recommended by Mitsubishi Electric.

• Do not make any modifications to the unit. For repairs, consult your dealer. Improper repair can result in water leakage, electric shock, or fire.

• Do not touch heat exchanger fins with bare hands as they are sharp and can cause cuts.

• If a refrigerant leak occurs, ventilate the room thoroughly. Toxic gases can be generated if the refrigerant comes into contact with an open flame.

• All electrical work must be done by an authorized electrician according to local regulations and instructions in the manual. Use a dedicated circuit.

• Keep electrical parts away from water to prevent electric shock, smoke, or fire.

• Securely attach the control box cover to prevent dust or water from entering, which could cause electric shock, smoke, or fire.

• When installing in a small space, prevent leaked refrigerant from reaching the limiting concentration, as it can displace oxygen and cause starvation.

• When moving or reinstalling the unit, consult your dealer or a qualified technician.

• After service work, check for any refrigerant leaks.

• Do not try to defeat safety features like pressure or temperature switches.

• For proper disposal, consult your dealer. Do not use a leak detection additive.

CAUTIONS for R410A Refrigerant:

• Do not use existing refrigerant piping. Residual chlorine from old refrigerant and oil can cause the new refrigerator oil to deteriorate.

• Use refrigerant piping made of phosphorus deoxidized copper. Keep pipe surfaces clean and free from contaminants like sulfur, oxides, dust, dirt, oil, and moisture.

• Store piping materials indoors with both ends sealed until brazing. Contaminants can cause the refrigerator oil to deteriorate or the compressor to malfunction.

• Use a small amount of ester oil, ether oil, or alkyl benzene to coat flares and flanges. A large amount of mineral oil can cause refrigerator oil deterioration.

• Charge the system with refrigerant in its liquid phase. Drawing gaseous refrigerant first will change the composition of the remaining refrigerant in the cylinder.

• Only use R410A refrigerant. Other refrigerants containing chloride may cause the refrigerator oil to deteriorate.

• Use a vacuum pump with a check valve to prevent pump oil from flowing into the refrigerant cycle.

• Prepare tools exclusively for use with R410A. Do not use tools (gauge manifold, charging hose, leak detector, etc.) that have been used with conventional refrigerants to avoid contamination.

• Do not use a charging cylinder, as it can alter the refrigerant composition.

• Exercise special care when handling tools to prevent dust, dirt, or water from entering the refrigerant system.

Specification	Value
Cooling Capacity (Nominal)	54,000 BTU/h / 15.8 kW
Heating Capacity (Nominal)	60,000 BTU/h / 17.6 kW

Button Number	Button Name/Function
1	[Set Temperature] Button
2	[Timer Menu] Button / [Monitor/Set] Button
3	[Mode] Button / [Back] Button
4	[Timer On/Off] Button / [Set Day] Button
5	[Louver] Button / [Operation] Button
6	[Fan Speed] Button
7	[Vane Control] Button
8	[Ventilation] Button / [Operation] Button
9	[Check/Clear] Button
10	[Test Run] Button
11	[Filter] Button / [▶] Button
12	[ON/OFF] Button
13	Position of built-in room thermistor
14	[Set Time] Button

Note: Keep the remote controller out of direct sunlight and ensure the thermistor at the lower right-hand section is free from obstructions for accurate room temperature measurement.

Indicator	Description
A	Current time/Timer time
B	Centralized control indicator
C	Timer OFF indicator
D	Timer mode indicator
E	Operation mode display: COOL, DRY, AUTO, FAN, HEAT
F	Function mode indicator
G	Preset temperature
H	Power indicator
I	Louver swing
J	Ventilation
K	Filter sign
L	Sensor position
M	Room temperature
N	Vane setting
O	Fan speed
P	Operation lamp

Model PEFY-P54NMAU-E3 Specifications
Power source	1-phase 208/230V 60Hz
Cooling capacity (Nominal)	54,000 BTU/h (15.8 kW)
Cooling Power input / Current input	0.36 kW / 2.24/2.20 A
Heating capacity (Nominal)	60,000 BTU/h (17.6 kW)
Heating Power input / Current input	0.34 kW / 2.13/2.09 A
External dimension H x W x D	9-7/8x63x28-7/8 in. (250 x 1600 x 732 mm)
Net weight	93 lbs (42 kg)
FAN Type x Quantity	Sirocco fan x 2
External static press.	<0.14>-<0.20>-<0.28>-<0.40>-<0.60> in.WG
Motor type / output	DC motor / 0.244 kW
Airflow rate (Low-Mid-High)	1042-1254-1483 cfm
Sound pressure level (Low-Mid-High)	36-41-45 dB <A>
Refrigerant pipe diameter (Liquid)	3/8 (9.52) in. (mm) Brazed
Refrigerant pipe diameter (Gas)	5/8 (15.88) in. (mm) Brazed
Diameter of drain pipe	O.D. 1-1/4(32) in. (mm)

Note: Nominal conditions are Indoor: 80degF D.B. / 67degF W.B. (Cooling), 70degF D.B. (Heating); Outdoor: 95degF D.B. (Cooling), 47degF D.B. / 43degF W.B. (Heating). External static pressure is set to 0.20in. WG(50Pa) at factory shipment.

Component	Symbol	Specification
Room temperature thermistor	TH21	Resistance 0°C/15kΩ, 10°C/9.6kΩ, 20°C/6.3kΩ, 25°C/5.4kΩ, 30°C/4.3kΩ, 40°C/3.0kΩ
Liquid pipe thermistor	TH22	Resistance 0°C/15kΩ, 10°C/9.6kΩ, 20°C/6.3kΩ, 25°C/5.4kΩ, 30°C/4.3kΩ, 40°C/3.0kΩ
Gas pipe thermistor	TH23	Resistance 0°C/15kΩ, 10°C/9.6kΩ, 20°C/6.3kΩ, 25°C/5.4kΩ, 30°C/4.3kΩ, 40°C/3.0kΩ
Fuse	FUSE	250V 6.3A
Fan motor	–	8-pole, Output 244W SIC-101CW-D8244-1
Linear expansion valve	LEV	12VDC Stepping motor drive port diameter ø3.2 (0~2000 pulse)
Power supply terminal block	TB2	(L1, L2, G) 250V 20A
Transmission terminal block	TB5, TB15	(1, 2) 250V 15A, (M1, M2, S) 250V 20A
Drain float switch	DS	Open/short detection, Initial contact resistance 500 mΩ or less

To operate in COOL mode:

1. Press the POWER [ON/OFF] button.

2. Press the operation [Mode] button to display COOL.

3. Press the [Set Temperature] button to set the desired temperature. The temperature changes by 2°F per press, with a range of 67°F to 87°F.

Control Functions in COOL mode:

• Thermoregulating function: The unit cycles to maintain the set temperature. Thermo ON occurs when the room temperature is ≥ desired temperature + 2°F. Thermo OFF occurs when the room temperature is ≤ desired temperature. There is a 3-minute restart prevention function.

• Anti-freezing control: If the liquid pipe temperature (TH22) drops to 33.8°F or less within 16 minutes of compressor start, anti-freezing control activates and turns the thermo OFF. Control is cancelled when the pipe temperature rises to 50°F or above, or the unit stops or changes mode.

• Fan: You can select from [Low], [Med], [High], and [Auto] speeds. In [Auto] mode, the fan speed changes based on the difference between the room temperature and the set temperature.

• Drain pump: The drain pump is always ON during COOL mode. When the mode is changed from COOL (or DRY) to another mode (including Stop), the pump continues to run for 3 minutes before turning OFF.

• Float switch control: The system detects if the float switch is in water by checking if it is ON for 15 seconds. If this occurs, it indicates a high water level.

To operate in DRY mode:

1. Press the POWER [ON/OFF] button.

2. Press the operation [Mode] button to display DRY.

3. Press the [Set Temperature] button to set the desired temperature. The temperature changes by 2°F per press, with a range of 67°F to 87°F.

Control Functions in DRY mode:

• Thermoregulating function: The unit cycles ON and OFF based on room temperature to dehumidify the air. The ON/OFF cycle time varies depending on the room temperature, as shown in the table below. There is a 3-minute restart prevention function.

Room temperature (T1)	Thermo ON time (min)	Thermo OFF time (min)
T1 ≥ 83°F	9	3
83°F > T1 ≥ 79°F	7	3
79°F > T1 ≥ 75°F	5	3
75°F > T1	3	3
Less than 64°F	Unconditional OFF	10

• Fan: The fan operates at [Low] speed when the thermo is ON. When the thermo is OFF, the fan stops, unless the room temperature is below 64°F, in which case it continues at [Low].

• Drain pump: Control is the same as in COOL mode.

To operate in FAN mode:

1. Press the POWER [ON/OFF] button.

2. Press the operation [Mode] button to display FAN.

Control Functions in FAN mode:

• Fan Speed: You can select from [Low], [Med], [High], and [Auto] speeds. When [Auto] is set, the fan speed defaults to [Low].

• Drain pump: The drain pump will turn ON for a specified time under these conditions:

– ON for 3 minutes after the operation mode is switched from COOL or DRY to FAN mode.

– ON for 6 minutes if the float switch control judges the sensor is in water.

To operate in HEAT mode:

1. Press the POWER [ON/OFF] button.

2. Press the operation [Mode] button to display HEAT.

3. Press the [Set Temperature] button to set the desired temperature. The temperature changes by 2°F per press, with a range of 63°F to 83°F.

Control Functions in HEAT mode:

• Thermoregulating function: The unit cycles to maintain the set temperature. Thermo ON occurs when the room temperature is ≤ desired temperature – 2°F. Thermo OFF occurs when the room temperature is ≥ desired temperature. There is a 3-minute restart prevention function.

• Fan: You can select from [Low], [Med], [High], and [Auto] speeds. In [Auto] mode, the fan speed changes based on the difference between the desired temperature and room temperature, with priority given to special control modes.

• Hot adjust mode: At the start of HEAT operation or when changing from Thermo OFF to ON, the fan runs at [Extra Low] or [Low] to prevent cold drafts. The remote controller will display “STAND BY”. The fan returns to the set speed after 5 minutes or when the indoor liquid pipe temperature reaches 95°F or more.

• Thermo OFF mode: When the thermoregulating function turns OFF the compressor, the indoor fan operates in [Extra low].

• Heat defrosting mode: The indoor fan stops during defrost operation.

• Drain pump: Control is the same as in FAN mode.

To operate in AUTO mode:

1. Press the POWER [ON/OFF] button.

2. Press the operation [Mode] button to display AUTO.

3. Press the [Set Temperature] button to set the desired temperature. The temperature changes by 2°F per press, with a range of 67°F to 83°F.

Automatic Changeover Operation:

• Initial mode: The unit starts in HEAT mode if the room temperature is less than the desired temperature, and in COOL mode if it is greater than or equal to the desired temperature.

• Mode change from HEAT to COOL: The unit switches to COOL mode if the room temperature becomes greater than the desired temperature + 3°F for 3 minutes or more.

• Mode change from COOL to HEAT: The unit switches to HEAT mode if the room temperature becomes less than or equal to the desired temperature – 3°F for 3 minutes or more.

• Operation in COOL/HEAT mode: Once a mode is selected, the unit operates with the same controls as in the standard COOL or HEAT mode.

To check the Room temperature thermistor (TH21), Liquid pipe thermistor (TH22), and Gas pipe thermistor (TH23):

1. Disconnect the thermistor connector from the control board.

2. Measure the resistance between its terminals with a multimeter.

3. Compare the measured resistance to the expected values. At an ambient temperature of 10°C – 30°C (50°F – 86°F), the normal resistance should be between 4.3 kΩ and 9.6 kΩ.

• Normal: Resistance is within the expected range (e.g., 4.3kΩ – 9.6kΩ).

• Abnormal: The circuit is open (infinite resistance) or shorted (near zero resistance).

Thermistor Resistance Characteristics:

Temperature (°C)	Temperature (°F)	Resistance (kΩ)
0°C	32°F	15
10°C	50°F	9.6
20°C	68°F	6.3
25°C	77°F	5.2
30°C	86°F	4.3
40°C	104°F	3.0

The LEV is a stepping motor that controls refrigerant flow. The indoor board sends pulse signals to change its position. When the unit is powered on, a signal of 2200 pulses is sent to ensure the valve is fully closed.

Checking the LEV Coils:

1. Disconnect the LEV connector (CN60) from the board.

2. Measure the resistance between the terminals with a multimeter.

3. Normal resistance between the coil pairs (White-Red, Yellow-Brown, Orange-Red, Blue-Brown) should be approximately 200 Ω ±10%.

4. If the resistance is incorrect, or the circuit is open or shorted, replace the LEV.

Troubleshooting Steps:

Symptom	Checking Criteria	Remedy
Circuit failure on the microcomputer	Disconnect the LEV connector and connect LEDs to the board pins to test the drive circuit. Pulse signals are output for 10 seconds when power is turned on. If LEDs do not light up or remain lit, there is a problem with the driving circuit.	Replace the indoor control board if the driving circuit fails.
Locked LEV	The motor will idle and make a small clicking noise if it is run while locked. Listen for this noise with a screwdriver against the valve body. If clicking is heard when the valve should be fully closed and while opening, it indicates a problem.	Replace the LEV.
Valve closure failure (leaky valve)	On the outdoor unit’s monitor, check the liquid pipe temperature of the indoor unit in question while it runs in FAN mode and other units are in COOL mode. If the LEV is leaky, the temperature will be significantly lower than the room’s inlet temperature.	Replace the LEV if the leakage is significant.

Drain-up Mechanism (Drain Pump):

1. Measure the resistance between terminals 1 and 3 of the drain pump connector.

2. At a coil temperature of 20°C (68°F), the normal resistance is 340 Ω.

3. If the reading is open or shorted, the drain pump is abnormal.

Drain Float Switch (CN4F):

1. Disconnect the float switch connector from the control board.

2. Measure the resistance (continuity) between the terminals while manually moving the float.

• Float Up: The switch should be shorted (continuity).

• Float Down: The switch should be open (no continuity).

3. If the switch does not function as described, it is abnormal.

CAUTION: A high voltage is applied to the fan motor connector (CNMF). Do not unplug it while the unit is energized.

Follow these troubleshooting steps:

1. Check Connector: Ensure the fan motor connector (CNMF) is fully and correctly inserted into the control board. If not, fix the connection.

2. Check Power Supply Voltage: Measure the DC voltage at the indoor control board between fan connector pins 1 (+) and 4 (-). The voltage should be between 294-340VDC depending on the AC supply (e.g., approx. 294VDC for 208VAC supply, 325VDC for 230VAC supply). If the voltage is not within the normal range, replace the indoor control board.

3. Check Control Voltage (Vcc): Measure the voltage between fan connector pins 5 (+) and 4 (-). It should be 15VDC. If not, replace the indoor control board.

4. Check Speed Command Voltage (Vsp): Measure the voltage between fan connector pins 6 (+) and 4 (-). This voltage should be between 1 – 6.5VDC when the fan motor is in operation and 0V when the fan is stopped. If the voltage is abnormal, replace the indoor control board.

5. Check Position Signal (VFG): Measure the voltage between fan connector pins 7 (+) and 4 (-). As the motor rotates, this voltage should alternate between 0VDC and 15VDC. If it does not, replace the motor. If it does alternate correctly but the fan still doesn’t run properly, replace the indoor control board.

Dipswitch settings must be made while the unit is stopped or powered off, as specified below. Power cycle the unit after changing SW1, SW2, or SW3 for the new settings to take effect.

SW1 – Function Setting:

Switch	Function	ON	OFF (Factory Setting)
1	Active Thermistor	Built-in on remote controller	Indoor unit intake air
4	Outdoor air intake	Enabled	Disabled
9	Auto restart after power failure	Enabled	Disabled

SW2 – Capacity Code Setting:

Set the switches to correspond to the unit capacity. For the PEFY-P54NMAU-E3, the setting is: Switch 1: ON, Switch 2: OFF, Switch 3: ON, Switch 4: OFF, Switch 5: ON, Switch 6: OFF.

SW3 – Unit Type Setting:

Switch	Function	ON	OFF (Factory Setting)
1	Unit type	Cooling only	Heat pump
4	Heater backup	Enabled	Disabled
8	Heating 4-deg up	Disabled	Enabled

SW5 – Power Voltage Setting (Operate with main power OFF):

• For 230 volts power supply, set SW5 to the 240V side.

• For 208 volts power supply, set SW5 to the 220V side.

SWA, SWC – External Static Pressure Setting:

These settings can be changed while the unit is running. The factory setting is 50Pa (0.20in.WG).

Static Pressure	SWA Setting	SWC Setting
35Pa (0.14in.WG)	OFF	OFF
50Pa (0.20in.WG)	ON	OFF
70Pa (0.28in.WG)	OFF	ON
100Pa (0.40in.WG)	ON	ON
150Pa (0.60in.WG)	ON	ON (with SWA set to ON)

Exercise caution when removing heavy parts.

1. Remove the control box cover: Remove the three fixing screws on the cover (A) to remove it.

When reassembling, tighten these screws to a torque of 2.0±0.2 N·m.

Exercise caution when removing heavy parts.

1. First, remove the control box cover as described in its removal procedure.

2. Pull out the thermistor holder (B) and the thermistor (C) from their position on the control box.

Exercise caution when removing heavy parts. Note: Drain the water out of the drain pan before removing it.

1. Remove the filter and bottom plate:

– Push down the tab on the filter and pull it out in the direction of arrow 1.

– Remove the fixing screws on the bottom plate (D), (E) to remove it. When reinstalling, tighten screws to a torque of 1.4±0.2 N·m.

2. Remove the drainpan:

– Pull out the drain pan in the direction of arrow 2.

Exercise caution when removing heavy parts.

1. First, remove the drain pan according to its removal procedure.

2. Remove the Heat Exchanger Cover: Remove the four fixing screws on the heat exchanger cover (F) to remove it. When reinstalling, tighten screws to a torque of 1.4±0.2 N·m.

3. Remove the Thermistor: Remove the thermistor (G) from the thermistor holder (H) on the copper tube.

Exercise caution when removing heavy parts.

1. Remove filter and bottom plate: Push down the tab on the filter to pull it out, then remove the fixing screws on the bottom plate (J) to remove it. (Tighten screws to 1.4±0.2 N·m upon reassembly).

2. Remove the fan casing (bottom half): Squeeze the tabs on the fan casing to remove it in the direction of arrow 2.

3. Remove the motor cable: Remove the motor cable through the rubber bush.

4. Remove the fan motor and Sirocco fan:

– Remove the two motor fixing screws to remove the motor and the Sirocco fan assembly in the direction of arrow 3. (Tighten screws to 3.5±0.2 N·m upon reassembly).

– Remove the four fan case fixing screws to take the top half of the fan casing off. (Tighten screws to 1.4±0.2 N·m upon reassembly).

Exercise caution when removing heavy parts.

1. Remove the drain pan according to its removal procedure.

2. Remove the heat exchanger cover according to its removal procedure.

3. Remove the support plate cover: Remove the five fixing screws on the pipe support plate cover (K) to remove it. (Tighten screws to 2.0±0.2 N·m upon reassembly).

4. Remove the Heat Exchanger: Remove the fixing screws on the heat exchanger (M) to remove it. (Tighten screws to 1.4±0.2 N·m upon reassembly).