TROUBLESHOOTING
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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.
"
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.
12.
TROUBLESHOOTING
"
The following table shows efficient checking procedures for trouble.
Fault
Possible Cause
Check/Corrective Action
Current to Unit is Shut Off
1. Reset the power supply line to the unit.
Fuse for Operation Circuit is Blown Out or
Faulty Contact
1. Check for shorted components.
2. Check for loose connection. Tighten or
replace. If necessary.
Contactor Holding Coil is Burned Out or
Faulty Contact
1. Find the causes, and repair or replace.
Tripped Overcurrent Relay
1. Remove the causes, and reset the
overcurrent relay.
Low Voltage
1. Check the voltage of unit rating.
Condenser Fan Does Not
Operate
Shorted Motor or Terminals.
1. Check the motor and terminals.
Repair or replace, if necessary.
Condenser Fan is Not Operating
1. Remove all causes of inoperative fan.
Interlock Circuit for Chilled Water Pump is
Open
1. Check the pump contactor. Repair or
replace, if necessary.
2. Check for the faulty pump.
Electrical Protective Devices Are Tripped.
1. Remove the causes, and reset the “ON”
button. See the following causes.
Compressor Does Not Operate
Incorrect Wiring Connection for Compressor
Power Source
1. Interchange two of three terminals R, S
and T at the main power source terminals.
Excessively High Discharge Pressure
1. See “High Discharge Pressure”
Compressor Stops on High
Pressure Switch
Malfunction of High Pressure Switch
1. Readjust the setting or replace, if defective.
Excessively High Discharge Pressure and
Suction Pressure
1. See “High Discharge Pressure” and “High
Suction Pressure”.
High or Low Voltage, Single-Phase or Phase
Imbalance
1. Check the power supply line and
contactors. Repair, if necessary.
Loose connection
1. Tighten the loose electrical connection or
repair, if necessary.
Faulty Compressor Motor
1. Check the compressor motor. Repair or
replace, if necessary.
Compressor Stops on
Overcurrent Relay
Faulty Overcurrent Relay
1. Replace it, if necessary.
