Mitsubishi Electric 250 YHA-A Installation Manual Download

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9. Special Functions

8.2. Unit replacement operation

Replacement operation is the operation by which impurities remaining in
the existing piping (chlorinated compounds) are captured by the activated
carbon filter (replacement filter) in the outdoor unit.

• This model will automatically begin the replacement operation after it has been

installed when it enters the initialization phase for normal heating or cooling. How-
ever, the unit will not automatically perform the replacement operation if it is moved
to a new location where it will be used with existing R22 refrigerant piping. Under
such conditions, always use the SW8-2 operations to perform the replacement
operation before beginning the test operation.

Replacement operation procedures (When moving the unit and connecting it
to existing R22 piping.)

Supply power.

Set DIP switch SW8-2 on the control board of the outdoor unit to ON to start
replacement operation.
* The replacement operation is performed using the cooling system. Cool air will

flow from the indoor unit during the replacement operation.

* During the replacement operation,

TEST RUN

is displayed on the remote controller

and LED1 and LED2 on the control board of the outdoor unit flash together.

The duration of the replacement operation is determined by the length of the pip-
ing. Always perform the replacement operation for longer than the stipulated time.
* Always perform one of the following operations at the completion of the re-

placement operation. The replacement operation will end and the unit will auto-
matically stop.

(1)Set SW8-2 from ON to OFF. (When ending a replacement operation of less

than 2 hours.)

• Each time SW8-2 is set from OFF to ON, the replacement operation can be

started. Always perform the replacement operation for longer than the stipu-
lated time.
Required replacement operation times

(2)The replacement operation will automatically stop after 2 hours. (It will end with

SW8-2 still in the ON position.)

• When the replacement operation has ended automatically after 2 hours of

operation, there is no need to set SW8-2 from ON to OFF; normal air condi-
tioning operations can are possible with the SW8-2 set to ON. Furthermore,
to repeat the replacement operation, SW8-2 will have to be returned to OFF
and then set to ON.

* If the indoor temperature is less than 15 °C, the compressor will operate

intermittently but the unit is not faulty.

8.3. Test run

8.3.1. Using SW4 in outdoor unit

SW4-1

Cooling operation

SW4-2

OFF

SW4-1

Heating operation

SW4-2

* After performing the test run, set SW4-1 to OFF.
• After power is supplied, a small clicking noise may be heard from the inside of the

outdoor unit. The electronic expansion valve is opening and closing. The unit is not
faulty.

• A few seconds after the compressor starts, a clanging noise may be heard from the

inside of the outdoor unit. The noise is coming from the check valve due to the small
difference in pressure in the pipes. The unit is not faulty.

The test run operation mode cannot be changed by DIP switch SW4-2 during
the test run. (To change the test run operation mode during the test run, stop
the test run by DIP switch SW4-1. After changing the test run operation mode,
resume the test run by switch SW4-1.)

8.3.2. Using remote controller

Refer to the indoor unit installation manual.

9.1. Low noise mode (on-site modification) (Fig. 9-1)

By performing the following modification, operation noise of the outdoor unit can be
reduced by about 3-4 dB.
The low noise mode will be activated when a commercially available timer or the
contact input of an ON/OFF switch is added to the CNDM connector (option) on the
control board of the outdoor unit.
• The ability varies according to the outdoor temperature and conditions, etc.

Complete the circuit as shown when using the external input adapter (PAC-
SC36NA). (Option)

SW1 ON: Low noise mode
SW1 OFF: Normal operation

9.2. Demand function (on-site modification) (Fig. 9-2)

• It is possible to reduce electricity consumption within a range from 0 to 100 percent

by performing the following on-site installation.
The demand function can be enabled by adding a commercially available input
contact point ON/OFF switch to the CNDM connector (the contact point demand
input, sold separately).

Incorporate the “Adaptor for external input (PAC-SC36NA)” into the circuit as shown
in the diagram on the left.

By switching SW7-1 and SW7-2 on the control circuit board for the outdoor unit,
the following power consumption restrictions (compared to rated power) can be
set.

Remote control panel

Relay circuit

External input adapter (PAC-SC36NA)

Outdoor unit control board

Relay power supply

Procure locally

Max. 10 m

Orange

Brown

Red

Fig. 9-1

Piping Length