Lennox INNOV DM R Series Application Manual page 100

10 Troubleshooting
On this pages you will find a list of the most common reasons that may cause the package unit to fail or any
malfunction. This causes are broken down according to easily identifiable symptoms.
You should be extremely careful when attempting to implement any of the possible remedies
suggested: overconfidence can result in injuries, even serious ones, to inexpert individuals.
Therefore, once the cause has been identified, you are advised to contact the manufacturer or a
qualified technician for help.
Tab. 9 Fault-Causes-Corrections
FAULT POSSIBLE CAUSES
No power supply.
The electronic card is cut off from the
power supply.
The unit does not start
Alarms have been released.
The phase sequence is wrong.
The compressor is The compressor is rotating in the
noisy wrong direction.
Insufficient airflow through the
condenser.
Presence of air in the refrigerant
circuit, as revealed by the presence of
Presence of abnormally
bubbles in the flow indicator also with
high pressure
sub-cooling values exceeding 5 °C.
Unit overcharged, as revealed by a
Sub-cooling of more than 8 °C.
Thermostatic valve and/or filter
obstructed. These symptoms may
also occur in the presence of an
abnormally low pressure.
Low condensation
Transducer fault.
pressure
Malfunctioning of thermostatic valve.
Filter dryer clogged.
Low evaporation
pressure
Low condensation temperature.
Low level of refrigerant.
The internal thermal protection device
has tripped.
The circuit breakers or line fuses have
been tripped by a short circuit.
The compressor
does not start
One of the HP or LP pressure
switches has tripped.
The phases have been inverted in the
distribution compartment.
Air in the cooling circuit During external connections.
The drain pan hole is closed.
Water out from the unit
The siphon is missing.
The air flow is too high.
INNOV@ CENT -AGU-0912-E
CORRECTIVE ACTIONS
Check if power is being supplied both to the primary and auxiliary
circuits.
Check the fuses.
Check whether any alarms are signalled on the microprocessor
control panel, eliminate the causes and restart the unit.
Invert two phases in the primary power line after disconnecting
them upstream from the unit.
Check the phase sequence relay. Invert the phases on the terminal
board after disconnecting the unit and contact the manufacturer.
Check for the presence of obstructions in the condenser section
ventilation circuit.
Check whether the condenser coil surface is obstructed.
Check the condensation control device (optional).
Drain and pressurise the circuit and check for leaks. Evacuate
slowly (for more than 3 hours) until reaching a pressure of 0.1 Pa
and then recharge in the liquid phase.
Drain the circuit.
Check the temperatures upstream and downstream from the valve
and filter and replace them if necessary.
Check the efficiency of the condensation control device (optional).
Warming the bulb with your hand, check whether the valve opens
and adjust it if necessary. If it does not respond, replace it.
Pressure drops upstream and downstream from the filter should not
exceed 2°C. If they do, replace the filter.
Check the efficiency of the condensation control device (where
present).
Check the refrigerant level by measuring the degree of Sub-cooling;
if it is below 2°C replenish the charge.
In the case of compressors equipped with a protection module,
check the thermal contact. Identify the causes after restarting.
Pinpoint the cause by measuring the resistance of the individual
windings and the insulation from the casing before restoring power.
Check on the microprocessor, eliminate the causes.
Check the phase sequence relay.
Open the valve positioned on the right side over the top of the coil.
Open the front panels, remove the sheet metal just below the e-
panel (down flow units) and clean it.
Check for the presence and provide for a new one.
Reduce the fan speed up to reaching the nominal air flow.
. 24 .