Operation Check; Inspection And Maintenance - Mitsubishi Electric City Multi PURY-P72TNU-A-BS Manuel D'installation

11-4. Operation check

The following symptoms are normal and do not indicate a problem.
Events
The auto vane automatically switches air flow direction.
The fan speed automatically changes during heating
operation.
The fan stops during heating operation.
The fan keeps running after the unit has stopped.
At the beginning of heating operation, the fan cannot be
manually set.
When the main power is turned on, the display as shown
right appears on the remote controller for about five
minutes.
The drain pump keeps running after the unit has
stopped.
The indoor unit emits noise when switching from heating
to cooling and vice versa.
Immediately after startup, the indoor unit emits the
sound of liquid flowing.
In a short while after the outdoor unit stops, the unit
makes a clicking sound.
Drain water comes out of the outdoor unit from the
bottom part of the heat exchanger.

12. Inspection and maintenance

Only qualified personnel must relocate or repair the unit. Do not attempt to disassemble or alter the unit.
- Failure to do so will result in refrigerant leakage, water leakage, serious injury, electric shock, or fire.
・While the unit is turned on, the compressor will remain energized even when it is stopped. Before inspecting the inside of the control box, turn off
the power, keep the unit off for at least 10 minutes, and confirm that the capacitor voltage (inverter main circuit) has dropped to 20 VDC or less. (It
takes about 10 minutes to discharge electricity after the power supply is turned off.)
・Control boxes house high-voltage and high-temperature electrical parts. They may still remain energized or hot after the power is turned off.
・Perform the service after disconnecting the connector (RYFAN1 and RYFAN2).
(To plug or unplug connectors, check that the outdoor unit fan is not rotating and that the voltage of capacitor in the main circuit is 20 VDC or
below. The capacitor may collect a charge and cause an electric shock when the outdoor unit fan rotates in windy conditions. Refer to the wiring
nameplate for details.)
Reconnect the connector (RYFAN1 and RYFAN2) after servicing.
・Unit components may be damaged after long use of the unit, resulting in a performance drop or the unit becoming a safety hazard. To use the unit
safely and maximize its life, it is recommended that a maintenance contract with a dealer or qualified personnel be signed. If the contract is
signed, service technicians will periodically inspect the unit to identify any damage at an early stage, and take appropriate measures.
・Please contact local MITSUBISHI ELECTRIC sales office for maintenance frequency and tasking recommendations.
・When the outdoor unit is installed on the waterproof sheet, the sheet may become dirty due to the copper component seeped out from the unit. In
this case, installing a drain pan for centralized drainage is recommended.
WT09106X03
Display on remote Cause
controller
Normal display The auto vane may switch over to horizontal air flow operation from vertical air flow operation in cooling mode if
the vertical air flow operation has been running for one hour. At defrost in heating mode or immediately after
heating start-up/shutdown, the auto vane automatically switches to horizontal air flow for a short time.
Normal display The fan operates at Very Low speed when the thermostat is turned off, and automatically changes over to the
preset speed according to the timer setting or refrigerant temperature when the thermostat is turned on.
"Defrost" The fan remains stopped during the defrost cycle.
No display After the unit has stopped during heating operation, the fan operates for one minute to exhaust heat.
"Stand By" The fan operates at Very Low speed for five minutes after heating operation starts or until the refrigerant
temperature reaches 35°C (95°F), then the fan operates at Low speed for two minutes, and finally the fan
operates at the preset speed.
"HO" or "PLEASE The system is starting up. Wait until "HO" or "PLEASE WAIT" stops blinking and goes off then try again.
WAIT" blinks.
No display The drain pump remains in operation for three minutes after the unit in cooling mode has stopped.
The drain pump goes into operation when drain water is detected, even when the unit is stopped.
Normal display This is a normal sound of the refrigerant circuit operating properly.
Normal display Unstable flow of the heating medium produces a sound. This is temporary and does not imply a problem.
No display After the unit stops and before the unit performs pressure equalization, the pressure difference temporarily
becomes small and the check valve may vibrate and make a sound. This is temporary and does not imply a
problem.
No display This ensures proper drainage of drain water in case the drain water freezes and remains in the outdoor unit
during the heating operation at low ambient temperature.
GB-47