Lennox ECOLOGIC Series User Manual

• 26 • Installation - Operation - Maintenance manual (IOM) • AIR COOLED CHILLERS & SPLIT UNITS - 0105-E
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 reciprocating +6°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
6.2.1.7 - Fan control pressure switch and thermostat:
The function of these devices is to ensure a level of head pressure compatible with proper unit operation.
An increase in outdoor air temperature increases head pressure, and this is maintained at its required value by fan
operation.
6.2.1.8 - Antifreeze function:
This function only exists on units designed for brine or glycol/water chilling for which the freezing temperature
depends on the concentration of the solution.
Whatever type of device is used (see case 1 and 2), cut-out by the antifreeze function causes immediate unit
stoppage.
CASE 1 : Antifreeze thermostat:
This device monitor chilled liquid temperature at the evaporator outlet. It triggers when the temperature goes below
the minimum value (+ 4°C for water).
CASE 2 : Antifreeze pressure switch:
This monitors evaporating pressure of the refrigerant. It triggers when the temperature goes below the preset
minimum value.
OPERATION

Lennox ECOLOGIC Series Specifications

General

Brand	Lennox
Model	ECOLOGIC Series
Category	Chiller
Language	English