Test Run; Special Functions - Mitsubishi Electric PUZ-HA24NHA1 Installation Manual

7. Test run

7.1. Before test run
After completing installation and the wiring and piping of the indoor and
outdoor units, check for refrigerant leakage, looseness in the power supply
or control wiring, wrong polarity, and no disconnection of one phase in the
supply.
Use a 500-volt megohmmeter to check that the resistance between the
power supply terminals and ground is at least 1 MΩ.
Do not carry out this test on the control wiring (low voltage circuit) terminals.
Warning:
Do not use the air conditioner if the insulation resistance is less than 1 MΩ.
Insulation resistance
After installation or after the power source to the unit has been cut for an extended
period, the insulation resistance will drop below 1 MΩ due to refrigerant accumulat-
ing in the compressor. This is not a malfunction. Perform the following procedures.
1. Remove the wires from the compressor and measure the insulation resistance of
the compressor.
2. If the insulation resistance is below 1 MΩ, the compressor is faulty or the resis-
tance dropped due the accumulation of refrigerant in the compressor.
3. After connecting the wires to the compressor, the compressor will start to warm
up after power is supplied. After supplying power for the times indicated below,
measure the insulation resistance again.
• The insulation resistance drops due to accumulation of refrigerant in the com-
pressor. The resistance will rise above 1 MΩ after the compressor is warmed
up for two to three hours.
(The time necessary to warm up the compressor varies according to atmo-
spheric conditions and refrigerant accumulation.)
7.2. Test run
7.2.1. Using SW4 in outdoor unit
SW4-1 ON
Cooling operation
SW4-2 OFF
SW4-1 ON
Heating operation
SW4-2 ON
* After performing the test run, set SW4-1 to OFF.

8. Special Functions

A
X
X
F
SW1
B
A Circuit diagram example (low noise mode)
B On-site arrangement
C External input adapter (PAC-SC36NA-E)
X: Relay
C D
CNDM
Orange
1
Brown
Fig. 8-1
Red
3
E
D Outdoor unit control board
E Max. 10 m, 33 ft
F Power supply for relay
• To operate the compressor with refrigerant accumulated in the compressor, the
compressor must be warmed up at least 12 hours to prevent breakdown.
4. If the insulation resistance rises above 1 MΩ, the compressor is not faulty.
Caution:
• The compressor will not operate unless the power supply phase connection
is correct.
• Turn on the power at least 12 hours before starting operation.
- Starting operation immediately after turning on the main power switch can result
in severe damage to internal parts. Keep the power switch turned on during the
operational season.
The followings must be checked as well.
• The outdoor unit is not faulty. LED1 and LED2 on the control board of the outdoor
unit flash when the outdoor unit is faulty.
• Both the gas and liquid stop valves are completely open.
• A protective sheet covers the surface of the DIP switch panel on the control board of
the outdoor unit. Remove the protective sheet to operate the DIP switches easily.
• Make sure that the all of the SW5 DIP switches for function changes on the con-
trol board of the outdoor unit are set to OFF. If all of the SW5 switches are not set
to OFF, record the settings and then set all of the switches to OFF. Begin recov-
ering the refrigerant. After moving the unit to a new location and completing the
test run, set the SW5 switches to the previously recorded settings.
• 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.)
7.2.2. Using remote controller
Refer to the indoor unit installation manual.
Note: Occasionally,vapor that is made by the defrost operation may seem as
if smoke come up from the outdoor unit.
8.1. Low noise mode (on-site modification) (Fig. 8-1)
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.
1 Complete the circuit as shown when using the external input adapter
(PAC-SC36NA-E). (Option)
2 SW7-1 (Outdoor unit control board): OFF (Operation of HA24)
3 SW1 ON: Low noise mode
SW1 OFF: Normal operation
en
10