Lennox INNOV DM R Series Application Manual page 58

10 Troubleshooting
On the next 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.
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 The compressor is rotating in the wrong
is noisy direction.
Insufficient airflow through the condenser.
Presence of air in the refrigerant circuit, as
Presence of
revealed by the presence of bubbles in the
abnormally high
flow indicator also with sub-cooling values
pressure
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.
Transducer fault.
Low
condensation
Wrong sentting of the condensation control
pressure
device
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
The compressor
tripped by a short circuit.
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
During external connections.
hydraulic circuit
The drain pan hole is closed.
Water out from
The siphon is missing.
the unit
The air flow is too high.
Unit is not prfectly levl
INNOV@ ECFAN DHR -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.
Replace the trasducer.
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 (only DX).
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.
Place correctly the unit.
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