Hitachi RAS-2-HVNP Service Manual page 205

8. Troubleshooting
Phenomenon
Foreign particles inside of the fan casing
Indoor unit fan runner is hitting the casing
Outdoor unit propeller fan is hitting the shroud
Cooling or heating proc-
ess with an abnormal
Abnormal sound from
sound
the compressor
Humming sound from the magnetic conductor
Outdoor fan does not
operate when the com-
Watching condition for the heating process
pressor operates
Discharge pressure does not increase higher than
Indoor fan does not
1.5 Mpa due to the insufficient refrigerant
operate when the com-
pressor operates
Disconnected Wiring for the Indoor Fan
N O T E
• *1): Refer to section Self-checking of the remote control switch.
• *2): Refer to section Self-checking procedure of PCB by means of the Remote Control Switch.
• *3): Even if the remote control switches are normal, the compressor does not operate under the following
conditions:
1. Indoor temp. is lower than 21 °C or outdoor temp. Is lower than -5 °C during the cooling process (DB).
2. Indoor temp. is higher than 27 °C (DB) or outdoor temp. is higher than 15 °C (WB) during the heating
process.
3. When a cooling (or heating) process signal is given to the outdoor unit and a different mode as heating (or
cooling) process signal is given to the indoor units.
4. When an emergency stop signal is given to outdoor unit.
• *4): Refer to chapter Piping work and refrigerant
• *5): Refer to chapter Test
191
SMGB0079 rev.0 - 01/2013
Cause
Faulty Installation
Liquid ref. compression
Wear or breakage of
the internal comp.
parts
No heating by the oil
heater
Abnormal vibration of the cabinets
Obstacle at the outdoor fan
charge.
run.
Check item
Visually inspect it
Visually inspect it
Visually inspect it
Check that each part is tightly
fixed
Adjust the suction gas temp.
and pressure
Abnormal Sound from the
Inside of the Compressor
Check the Resistance (Oil
Heater, Fuse)
Check the surface of the
contacts
Check each fixing screw
Check the obstacles
Wait for the switching of the
4-Way Valve (1 ~ 3 minutes)
Check the operation pressure
*5)
Check the wiring
Action
(Turn OFF the main switch)
Remove the foreign particles
Adjust the position of the fan
runner
Adjust the position of the
propeller fan
Tightly fix each part
Ensure superheat
Replace the compressor
Replace the oil heater or the
fuse
Replace the magnetic switch
Tightly fix each screw
Remove the obstacles
If the 4-Way Valve does not
switch, check for insufficient
refrigerant
Add the refrigerant
Connect the wiring correctly
8