Lennox INNOV DM R Series Application Manual page 93

7 Starting Up
7.1 Preliminary checks
D Check that the electrical connections have been made properly and that all the terminals are securely
tightened. This check should also be included in a periodic six-month inspection.
D Check that the voltage at the RST terminals is 400 V ± 5% and make sure the yellow indicator light of the
phase sequence relay is on. The phase sequence relay is positioned on the electric control board; if the
sequence is not duly observed, it will not enable the machine to start.
D Make sure there are no refrigerant leaks that may have been caused by accidental impacts during transport
and/or installation.
D Check the power supply to the crankcase heating elements, where present.
The heating elements must be turned on at least 12 hours before the unit is started.
They are automatically activated when the main switch is put on. Their function is to raise the T
of the oil in the sump and limit the quantity of refrigerant dissolved in it.
To verify whether the heating elements are working properly, check the lower part of the compressors: it should
be warm or in any case at a temperature 10 - 15 °C higher than the ambient temperature.
Fig. 12 Charles' law diagram
Pressure
The diagram above illustrates a specific property of gases (Charles' Law), which are more soluble in liquids as
the pressure increases but less soluble as the temperature increases: if the oil in the sump is held at a constant
pressure, an increase in temperature will significantly reduce the amount of refrigerant dissolved in it, thus
ensuring that the desired lubricating function is maintained.
7.2 Starting operation
Before starting the unit, turn the main switch on, select the operating mode desired from the control panel and
press the "On" button on the control panel.
If the unit fails to start up, check if the service thermostat has been set according to the nominal values
provided.
You should not disconnect the unit from the power supply during periods when it is inoperative
but only when it is to be taken out of service for a prolonged period (e.g. at the end of the
season).
7.3 Checks during operation
D Check the phase sequence relay on the control board to verify whether the phases occur in the correct
sequence: if they do not, disconnect the unit from power supply and invert two phases of the incoming three-
pole
Never attempt to modify internal electrical connections: any undue modifications will immediately invalidate
the warranty.
INNOV@ CENT -AGU-0912-E
T
T3
Oil
T2
T1
% R407C in oil
cable.
. 17 .