Lennox MCC Series, Инструкция по установке, эксплуатации и обслуживанию

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Installation - Operation - Maintenance manual (IOM) • AIR COOLED CHILLERS & SPLIT UNITS - 1106-E
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OPERATION
6 - OPERATION
6.1 - CLIMATIC CONTROL
cf. See the specific CLIMATIC 50 manual
cf. See the specific «Basic CLIMATIC controller» manual
6.2 - UNIT OPERATION
6.2.1 - Functions of refrigeration circuit components
6.2.1.1 - Thermostatic expansion valve:
Very important:
The thermostatic expansion valve fitted on each machine has been selected for a given operating range; it must be
replaced with a model with the same reference from the same manufacturer.
6.2.1.2 - Filter-drier:
This is designed to remove all traces of humidity from within the refrigeration circuit, since this can impair operation of
the unit, by acidification of the oil, which causes slow disintegration of the varnish protecting the compressor motor
windings.
6.2.1.3 - High and low pressure gauges (option): Enables instantaneous readout of suction and discharge
pressures.
Sightglass/humidity indicator: (optional on units fitted with scroll type or reciprocating compressors) :
- Enables visual verification of the state of the liquid refrigerant (monophase ou diphasic) in the liquid line, upstream
of the thermostatic expansion valve.
- Enables detection of humidity in the circuit.
6.2.1.4 - Crankcase heater:
Every compressor is fitted with a single phase crankcase heater that is activated when the compressor stops to
ensure separation of the refrigerant and the compressor oil. It is therefore powered up when the compressor is not
running.
NB : Scroll and recipro6°C ambient type compressors are not fitted with a crankcase heater.
6.2.1.5 - High pressure switch:
This pressostat initiates unconditional stoppage of the unit if compressor discharge pressure exceeds the operating
limits. Reset is automatic.
- Screw and reciprocating compressor with R407C high pressure switch equal 26.5 bars
- Scroll compressor with R407C high pressure switch equal 29 bars
6.2.1.6 - Low pressure switch:
This pressure switch initiates unconditional stoppage of the unit if if evaporating pressure drops below the value P.
- 1) +6°C ambient temperature machines (standard) P = 2,4 bars relative
- 2) optional -20°C ambient temperature machines P = 0,8 bars relative