Sevicing For R407C Refrigerant System; Troubleshooting - Hitachi RCUE40AG1 Installation, Operation And Maintenance Instructions

11.16. SERVICING FOR R407C REFRIGERANT SYSTEM
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Refrigerant
This R407C refrigerant is HFC type so that it has a feature
of no ozone depletion. If it is mixed with another refrigerant,
the serious changing would occur on its character.
Therefore notice the following point when handling this
refrigerant.
1. Charge the refrigerant in LIQUID condition and NOT in
GAS. As "R407C" is geotropic mixed refrigerant, if gas
charging is performed, only the easy vaporising
refrigerant would be charged into the system and the
difficult vaporising one would be remained in the charge
cylinder.
The cylinder, gauge equipped manifold and charge hose
are only used for R407C refrigerant.
Adjust the cylinder setting to charge in liquid.

12. TROUBLESHOOTING

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The following table shows efficient checking procedures for trouble.
Fault
Condenser Fan Does Not
Operate
Compressor Does Not Operate
Compressor Stops on High
Pressure Switch
Compressor Stops on
Overcurrent Relay
Possible Cause
Current to Unit is Shut Off
Fuse for Operation Circuit is Blown Out or
Faulty Contact
Contactor Holding Coil is Burned Out or
Faulty Contact
Tripped Overcurrent Relay
Low Voltage
Shorted Motor or Terminals.
Condenser Fan is Not Operating
Interlock Circuit for Chilled Water Pump is
Open
Electrical Protective Devices Are Tripped.
Incorrect Wiring Connection for Compressor
Power Source
Excessively High Discharge Pressure
Malfunction of High Pressure Switch
Excessively High Discharge Pressure and
Suction Pressure
High or Low Voltage, Single-Phase or Phase
Imbalance
Loose connection
Faulty Compressor Motor
Faulty Overcurrent Relay
TROUBLESHOOTING
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Refrigerant Oil
Castrol's "Icematic" SW220HT, which R407C refrigerant is
easy to blend into it, is used for this system. The other oil is
prohibited to use, so that not to be mixed with another kind
of oil at the maintenance and service work. This oil is very
hygroscopic.
Therefore minimum humidity handling is necessary.
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Servicing Equipment
When servicing R407C system, servicing equipment such
as Charging Cylinder, Charging Hose, Vacuum Pump and
so on, shall not be mixed with R22 equipment to avoid
R407C composition change.
Check/Corrective Action
1. Reset the power supply line to the unit.
1. Check for shorted components.
2. Check for loose connection. Tighten or
replace. If necessary.
1. Find the causes, and repair or replace.
1. Remove the causes, and reset the
overcurrent relay.
1. Check the voltage of unit rating.
1. Check the motor and terminals.
Repair or replace, if necessary.
1. Remove all causes of inoperative fan.
1. Check the pump contactor. Repair or
replace, if necessary.
2. Check for the faulty pump.
1. Remove the causes, and reset the "ON"
button. See the following causes.
1. Interchange two of three terminals R, S
and T at the main power source terminals.
1. See "High Discharge Pressure"
1. Readjust the setting or replace, if defective.
1. See "High Discharge Pressure" and "High
Suction Pressure".
1. Check the power supply line and
contactors. Repair, if necessary.
1. Tighten the loose electrical connection or
repair, if necessary.
1. Check the compressor motor. Repair or
replace, if necessary.
1. Replace it, if necessary.
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