• When thermistor is abnormal. (When the LED display is a table below.)

F Check of thermistor

LED

Thermistor

Symbol

Connector, Pin No.

E7

Defrost thermistor

RT62

Between CN661 pin1 and pin2

E6

Discharge temperature thermistor

RT61

Between CN661 pin3 and pin4

E9

Evaporation temperature thermistor

RT63

Between CN661 pin5 and pin6

F5

Gas pipe temperature thermistor (Unit A)

RT66

Between CN662 pin1 and pin2

F6

Gas pipe temperature thermistor (Unit B)

RT67

Between CN662 pin3 and pin4

F7

Gas pipe temperature thermistor (Unit C)

RT68

Between CN662 pin5 and pin6

d4

Fin temperature thermistor

RT65

Between CN663 pin1 and pin2

Start

Disconnect the connector in the electronic control P. C. board (see above table), and

Abnormal

measure the resistance of thermistor to check whether the thermistor is normal or not.

 

 

Normal

 

 

 

Replace the thermistor

Reconnect the connector (CN661, CN662 and CN663) and disconnect the lead wire leading to the compressor. Turn on power supply to the indoor and outdoor unit. Three minutes later EMERGENCY OPERATION starts.

Does thermistor operate 10 minutes or more though the No thermistor abnormality is not displayed?

Yes

Normal

Replace the electronic control P. C. board.

• Fan motor does not operate. Or, fan motor stops at once’ after fan motor operates.

G Check of fan motor

Start

Check the connection of connector (CN851, CN852) in the fan motor relay connector and electronic control P. C. board at the noise filter P. C. board and connector (CN901, CN902) in the noise filter board.

Disconnect the fan motor connector, and measure the resistance of the

Abnormal

 

Replace the fan motor

fan motor winding to check the winding characteristic.

 

 

 

 

 

 

Normal

 

 

 

 

 

 

 

1.Disconnect the lead wire leading to the compressor. Turn on power supply to the indoor and outdoor unit. Three minutes later, EMERGENCY OPERATION starts.

2.Check the voltage between pin 2 and pin 3, pin 2 and pin 5, pin 2 and pin 6 at the fan motor connector.

Is there voltage of 230V AC?

No

Yes

1.

Turn off power supply of the indoor and outdoor unit, and disconnect the connector

 

 

 

 

 

(CN851, CN852).

No

Replace the electronic

2.

Is the voltage 0V, when the voltage between CN852 pin1 (+) and CN851 pin1 (-),

 

 

control P. C. board

 

pin2 (-), or pin3 (-) are measured after the power supply is turned on the outdoor unit?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Yes

 

 

 

 

 

 

 

 

 

 

Is there voltage of 12V DC between CN852 pin1 (+) and pin3 (-), when power supply

No

 

turns on the indoor unit and EMERGENCY OPERATION starts in three minutes.

 

 

 

 

Yes

Replace the noise filter P. C. board

31

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Mitsubishi Electronics MXZ-24UV - E2 service manual Led

MXZ-24UV - E2, MXZ-24UV specifications

Mitsubishi Electronics has established itself as a leader in the HVAC (heating, ventilation, and air conditioning) industry with its MXZ-24UV and MXZ-24UV - E2 models. These multi-zone heat pump systems are designed to provide exceptional efficiency, comfort, and versatility for residential and commercial applications.

One of the main features of the MXZ-24UV is its ability to effectively cool and heat multiple rooms simultaneously. This system allows for the connection of up to four indoor units, enabling users to customize the climate in different spaces while maintaining energy efficiency. This zoning capability ensures you can maintain the perfect temperature in each room according to the occupants' preferences.

The MXZ-24UV incorporates advanced inverter technology, which allows the compressor to adjust its speed based on the required heating or cooling demand. This results in reduced energy consumption compared to conventional systems, providing significant savings on energy bills while also promoting a more consistent indoor temperature. The inverter-driven compressor operates quietly and efficiently, making it a suitable choice for residential areas.

Additionally, these models are equipped with a range of smart technologies. The built-in Wi-Fi capability allows homeowners to control the system remotely using a smartphone or tablet. This feature adds convenience and flexibility, enabling users to adjust settings from anywhere, ensuring their space is at the desired temperature upon arrival.

Durability is another essential characteristic of the MXZ-24UV and MXZ-24UV - E2 models. Mitsubishi has designed these units to withstand various weather conditions, enhancing longevity and reliability. The units feature a robust construction that minimizes wear and tear while ensuring dependable performance year after year.

Moreover, the system has a variety of indoor unit options, including wall-mounted, ceiling-mounted, and floor-mounted designs. This versatility makes it easy to integrate into different architectural styles and preferences, ensuring both aesthetics and functionality.

In summary, the Mitsubishi Electronics MXZ-24UV and MXZ-24UV - E2 models are designed for those seeking energy efficiency, flexibility, and durability in a multi-zone heating and cooling system. With advanced inverter technology, smart home capabilities, and a range of indoor unit styles, these systems offer exceptional comfort while minimizing energy costs, making them a top choice in the HVAC market.