MITSUBISHI ELECTRIC PEFY-P27NMAU-E3 (01) PDF DOCUMENT

Please observe the following safety precautions for your safety before installation and performing electrical work:

Installation and Repair:

• Ask your dealer or a qualified technician to install the unit. Improper installation may result in water leakage, electric shock, or fire.

• Have all electrical work performed by an authorized electrician according to local regulations and the instructions in this manual. Use a dedicated circuit.

• Properly install the unit on a surface that can withstand its weight. An unstable surface may cause the unit to fall and cause injury.

• Only use specified cables. Securely connect each cable so that the terminals do not carry the weight of the cable. Improperly connected cables may produce heat and start a fire.

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

• Only use accessories (e.g., air cleaners, humidifiers, electric heaters) recommended by Mitsubishi Electric.

• Do not make any modifications or alterations to the unit. Consult your dealer for repair, as improper repair may result in water leakage, electric shock, or fire.

Operation and Maintenance:

• Do not use refrigerant other than the type indicated in the manuals (R410A). Doing so may cause the unit or pipes to burst, or result in an explosion or fire.

• In the event of a refrigerant leak, thoroughly ventilate the room. If gaseous refrigerant comes in contact with an open flame, toxic gases will be generated.

• Do not touch the heat exchanger fins with bare hands. The fins are sharp and pose a risk of cuts.

• Keep electrical parts away from water. Wet electrical parts pose a risk of electric shock, smoke, or fire.

• Securely attach the control box cover. If the cover is not installed properly, dust or water may infiltrate and cause an electric shock, smoke, or fire.

• Do not try to defeat the safety features of the unit, such as the pressure switch or temperature switch.

When handling units that use R410A refrigerant, please follow these precautions:

Piping and Oil:

• Do not use existing refrigerant piping, as residual chlorine may cause the new unit’s refrigerator oil to deteriorate.

• Use refrigerant piping materials made of phosphorus deoxidized copper. Keep pipes clean and free of contaminants.

• Store piping materials indoors and keep both ends sealed until brazing.

• Use a small amount of ester oil, ether oil, or alkyl benzene to coat flares and flanges. Infiltration of a large amount of mineral oil may cause the refrigerator oil to deteriorate.

Tools and Equipment:

• Only use R410A refrigerant. The use of other refrigerants 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 for exclusive use with R410A. Do not use tools that have been used with conventional refrigerants (gauge manifold, charging hose, gas leak detector, etc.).

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

Charging:

• Charge the system with refrigerant in the liquid phase. If gaseous refrigerant is drawn out first, the composition of the remaining refrigerant in the cylinder will change and become unsuitable for use.

Model		PEFY-P27NMAU-E3
Power source		1-phase 208/230V 60Hz
Cooling capacity (Nominal)	*1 BTU/h	27,000
	*1 kW	7.9
	Power input kW	0.17
	Current input A	1.31/1.27
Heating capacity (Nominal)	*2 BTU/h	30,000
	*2 kW	8.8
	Power input kW	0.15
	Current input A	1.20/1.16
External finish		Galvanized steel plate
External dimension H x W x D	in.	9-7/8×43-5/16×28-7/8
	mm	250 x 1100 x 732
Net weight lbs (kg)		67(30)
Heat exchanger		Cross fin (Aluminium fin and copper tube)
FAN	Type x Quantity	Sirocco fan x 2
	External static press. in.WG (Pa)	<0.14>-0.20-<0.28>-<0.40>-<0.60> (<35>-50-<70>-<100>-<150>)
	Motor type	DC motor
	Motor output kW	0.121
Driving mechanism		Direct-driven by motor
Airflow rate (Low-Mid-High)	cfm	618-742-883
	m³/min	17.5-21.0-25.0
	L/s	292-350-417
Sound pressure level (Low-Mid-High) dB <A> (measured in anechoic room)		30-34-39
Insulation material		EPS, Polyethylene foam, Urethane foam
Air filter		PP honeycomb fabric
Protection device		Fuse
Refrigerant control device		LEV
Connectable outdoor unit		R410A CITY MULTI
Diameter of refrigerant pipe (O.D.)	Liquid (R410A) in. (mm)	3/8 (9.52) Brazed
	Gas (R410A) in. (mm)	5/8 (15.88) Brazed
Diameter of drain pipe in. (mm)		O.D. 1-1/4(32)
Optional parts		External heater adapter: PAC-YU25HT, Filter box: PAC-KE93TB-E

Note:

*1 Nominal cooling conditions: Indoor 80°F D.B. / 67°F W.B., Outdoor 95°F D.B.

*2 Nominal heating conditions: Indoor 70°F D.B., Outdoor 47°F D.B. / 43°F W.B.

Pipe length: 25 ft. (7.6 m), Level difference: 0 ft. (0 m).

The external static pressure is set to 0.20in. WG (50Pa) at factory shipment.

Due to continuing improvement, above specifications may be subject to change without notice.

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 121W SIC-70CW-D8121-1
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 the unit 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 set temperature changes 2°F each time the [Set Temperature] button is pressed. The cooling temperature range is from 67°F to 87°F.

The unit uses a thermoregulating function where it turns on (Thermo ON) when the room temperature is greater than or equal to the desired temperature + 2°F, and turns off (Thermo OFF) when the room temperature is less than or equal to the desired temperature.

To operate the unit 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 set temperature changes 2°F each time the [Set Temperature] button is pressed. The dry temperature range is from 67°F to 87°F.

The Dry thermo function operates based on room temperature and the thermo regulating signal, with specific ON and OFF time cycles as detailed in the table below:

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

To operate the unit in Fan only mode:

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

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

You can set the fan speed to [Low], [Med], [High], or [Auto]. When [Auto] is set, the fan speed becomes [Low].

To operate the unit 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 set temperature changes 2°F each time the [Set Temperature] button is pressed. The heating temperature range is from 63°F to 83°F.

The unit uses a thermoregulating function where it turns on (Thermo ON) when the room temperature is less than or equal to the desired temperature – 2°F, and turns off (Thermo OFF) when the room temperature is greater than or equal to the desired temperature.

During heat operation, the remote controller may display [DEFROST] during the defrost cycle or [STANDBY] during the hot adjust mode.

To use the Automatic 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 set temperature changes 2°F each time the button is pressed, with a range of 67°F to 83°F.

Mode Operation:

• The unit will initially start in HEAT mode if the room temperature is less than the desired temperature, or in COOL mode if the room temperature is greater than or equal to the desired temperature.

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

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

Drain Pump Control:

• In COOL and DRY modes, the drain pump is always ON, regardless of the thermo ON/OFF status.

• When the operation mode is changed from COOL or DRY to another mode (including Stop), the drain pump continues to run for 3 minutes before turning off.

• If the float switch detects water, the drain pump will turn ON for 6 minutes.

Float Switch Control:

• The float switch control determines if the sensor is in air or water by turning the float switch ON/OFF.

• Water is detected if the float switch is ON for 15 consecutive seconds.

• Air is detected if the float switch is OFF for 15 consecutive seconds.

• An abnormal condition is registered if the system cycles between detecting water and air repeatedly, leading to an error.

Thermistor Check (TH21, TH22, TH23):

Disconnect the thermistor connector and measure the resistance with a tester. At an ambient temperature of 50°F to 86°F (10°C to 30°C), the resistance should be between 4.3kΩ and 9.6kΩ. An “Open or short” reading indicates an abnormality. Resistance values at various temperatures are:

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

Linear Expansion Valve (LEV):

Disconnect the connector and measure the resistance between the terminals. The normal resistance is 200Ω ±10% between the following color-coded wire pairs: White-Red, Yellow-Brown, Orange-Red, and Blue-Brown.

Drain-up Mechanism:

Measure the resistance between terminals 1 and 3. At a coil temperature of 68°F (20°C), the resistance should be approximately 340Ω. An “Open or short” reading is abnormal.

Drain Float Switch (CN4F):

Disconnect the connector and check for continuity. When the moving part is in the “Up” position, there should be a short. When it is in the “Down” position, it should be open. Any other reading indicates an abnormality.

Follow these troubleshooting steps if the indoor unit fan is not running:

1. Check Connector: Ensure the fan motor connector (CNMF) is fully inserted into the indoor control board.

2. Check Power Supply: Measure the DC voltage at the indoor control board between fan connector pins 1 (+) and 4 (-). The voltage should correspond to the AC power supply as follows:

• 208VAC -> 294VDC
• 220VAC -> 311VDC
• 230VAC -> 325VDC
• 240VAC -> 340VDC

Also, check for 15VDC between pins 5 (+) and 4 (-).

3. Check Control Voltage: While the fan should be in operation, check the voltage between pins 6 (+) and 4 (-). It should be between 1 – 6.5VDC. When the fan is stopped, it should be 0V.

4. Check Position Signal: Measure the voltage at the test point VFG (between fan connector pins 7 (+) and 4 (-)) while rotating the motor manually for at least one full rotation. The voltage should alternate between 0VDC and 15VDC. If it does not, replace the motor. If it does, replace the indoor control board.

If the voltages are not within the normal range at any step, replace the indoor control board.

Ensure the power to the unit is turned off before setting the address. On-site address setting is required for the indoor units to run.

The address is set using a combination of two rotary switches on the indoor unit control board: SW12 (for the 10’s digit) and SW11 (for the 1’s digit).

For example:

• To set the address to “3”, set SW12 to “0” and SW11 to “3”.

• To set the address to “25”, set SW12 to “2” and SW11 to “5”.

Address setting is required when using an ME remote controller. It is not required when using a standard unit remote controller.

The external static pressure is set using the dipswitches SWA and SWC on the indoor control board. The factory setting is 50Pa (0.20in.WG). Changes to these dipswitches become effective immediately, regardless of the unit’s operation status (RUN/STOP).

The available settings are:

• 35Pa (0.14in.WG)
• 50Pa (0.20in.WG)
• 70Pa (0.28in.WG)
• 100Pa (0.40in.WG)
• 150Pa (0.60in.WG)

Refer to the diagrams on the control board for the specific ON/OFF positions for each setting.

Exercise caution when removing heavy parts. To remove the control box:

1. First, remove the control box cover.

2. Remove the three fixing screws on the cover to remove it.

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

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

1. Remove the Filter and Bottom Plate:

– Push down the tab on the filter and pull it out.

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

2. Remove the Drain Pan:

– Pull out the drain pan in the direction indicated by the arrow in the service manual diagram.

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 to remove it. (Tighten screws to 1.4±0.2 N.m on reassembly).

2. Remove Fan Casing (Bottom Half): Squeeze the tabs on the fan casing to remove the bottom half.

3. Remove Motor Cable: Remove the motor cable from the rubber bush.

4. Remove Fan Motor and Sirocco Fan:

– Remove the two motor fixing screws to remove the motor and the Sirocco fan assembly.

– (Tighten motor fixing screws to 3.5±0.2 N.m on reassembly).

5. Separate Fan Casing (Top Half): 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 on reassembly).