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Close the power circuit-breaker or the fan motor cut-outs.
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Start up compressor by switching the on/off switch to on.
The current increases to maximum and must decrease very rapidly. If this does not happen, stop the compressor to check and
find the fault.
Remainder of charge
Fill up with the remainder very quickly.
An incomplete charge of fluid will cause considerable superheat and so abnormally high discharge temperatures.
OPERATING CHECKS
Shortly after start-up, the operating conditions of the equipment must be checked
Compressor
The compressor must operate within its acceptable limits
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(see Manufacturer's advice).
Check on each compressor:
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Voltage
Discharge pressure
Measure suction temperature
Measure discharge temperature
Measure crankcase temperature acting at the oil drain plug.
The intake superheat must not exceed 20K and should not fall below 10K.
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and ensure that the charge in the condensing unit is correct.
The discharge temperatures on the high pressure line must be within the following range:
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. R404/507
70°C <
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The crankcase temperature must not fall below 40°/45°C
Very important:
There is no need to add oil over and above the required quantity during start-up. Wait several hours.
Excess oil generally leads to oil slugs on the condensing unit which causes damage to the compressors.
. If oil level is low, this could be caused by:
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Too much oil being entrained by emulsification in the crankcases resulting in an excessive amount of refrigerant fluid being
dissolved into the oil (superheat too low at suction inlet - crankcase heater defective or not energised).
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Bad design of the LP piping on the equipment trapping the oil, particularly when running with reduced refrigerant charge.
MAINTENANCE
RECOMMENDATIONS
If the unit is stopped for long periods of time, the fan motors should be run for at least two hours each week.
. Every month:
Carry out an operating check on:
Pressures and temperatures in the compressor
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Voltages in compressors and fan motors
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Safety cut-off points of HP/LP safety pressure switches.
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Oil levels
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Moisture in the circuits (through sight-glass or by analysing oil)
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Check for leaks in the refrigeration circuit
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.Every year:
Carry out an analysis of the oil
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In the case of HFC type fluid ( R404A ), activated aluminium oxide dryers should be avoided, dryers with a molecular
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filter should be chosen instead.
Instructions or recommendations appearing in the various technical advice notes and manufacturer's service manuals should be
followed precisely; please contact our Technical Department for any additional information.
T° discharge
< 100°C
.
Therefore adjust the thermostatic expansion valve
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