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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6.2.2.4 - Indicator lights:
The electrical control box is fitted with indicator lights enabling visualisation of the state of operation or non operation
of a function or given circuit.
There is also an indicator to show that the unit is powered up, an emergency stoppage indicator for each compressor,
an indicator to show stoppage of the compressor via the regulating system (through the main control thermostat
which is sensitive to chilled water temperature), a run light per compressor, and a general fan default stoppage
indicator (on air cooled units).
On units with CLIMATIC control, see the appropriate manual.
6.2.2.5 - Time delay relay for starting compressor motors one winding at a time (option) :
This optional relay is supplied on units ordered with the part winding start system. The time delay between starting
the first winding and the second winding cannot exceed 0.8 seconds.
6.2.2.6 - Chilled liquid pump interlock:
This interlock is made only if the the pump is supplied with the liquid chiller. As soon as the unit is powered up and
the remote on/off for the unit is validated, the pump starts running. Prior operation of the pumps is mandatory for
compressor operation.
Note : on units with CLIMATIC control, control of 1 or 2 water pumps is catered for by the control program.
6.2.2.7 - Flow switch for the chilled liquid (option) :
This control device initiates unconditional unit stoppage as soon as the flow of chilled liquid (water, brine, etc...)
ensured by the pump becomes insufficient, since this could cause rapid evaporator freeze up. When the contact
opens due to a lack of flow the unit must stop immediately.
If the purchaser installs a flow switch himself, electrical connections should be made to the two remote interlock
terminals (dry contact).
6.2.3 - Automatic sequences
6.2.3.1 - Starting sequence:
- Press the unit start switch, the power light will come on ; The control circuit cannot be energised if there is no
power supply to the main power circuit.
- Depending on the demand for cooling, the control thermostat authorises start up of the compressor(s), which takes
place in sequence. The compressor run indicating lights come on.
6.2.3.2 - Regulator stoppage sequence :
When the cooling load starts decreasing from its maximum value, the multi-stage control thermostat shuts
down successive stages depending on the progressive reduction in return chilled liquid temperature.
Depending on machine equipment, staged reduction consists either in shutting down a compressor or activation of a
compressor capacity reducer. This continues until the unit shuts down completely through action of the regulator. The
compressor regulation stoppage lights come on.
6.2.3.3 - Safety shutdown sequence :
If a default occurs on a circuit, it is detected by the appropriate safety device, (high pressure overshoot, loss of oil
pressure, motor protection, etc...) The relay in question initiates unconditional stoppage of the compressor on that
circuit and the safety stoppage indicating light comes on.
Some defaults give rise to immediate stoppage of the entire unit :
- Tripped flow switch,
- Tripped antifreeze thermostat
- ...etc....