Lennox INNOV DM R Series Application Manual page 50

7 Start-Up
7.1 Preliminary checks
·
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.
· Check that the voltage at the RST terminals is 400 V ± 10% and make sure the yellow indicator light of the
phase sequence relay is on (only DX versions). 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.
· Make sure there are no refrigerant leakage that may have been caused by accidental impacts during
transport and/or installation (monobloc unit).
·
Check the power supply to the crankcase heater, 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 operations
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).
INNOV@ ECFAN DHR -AGU-0912-E
T oil
T2
T1
T0
% of R410A in oil
• 18 •