Lennox INNOV DM R Series, Application Manual

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INNOV@ ECFAN DMR -AGU-0912-E • 22 •
11 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 .
Tab. 10 Fault-Causes-Corrections
FAULT POSSIBLE CAUSES CORRECTIVE ACTIONS
The unit does
not start
No power supply. Check if power is being supplied both to the primary and auxiliary circuits.
The electronic card is cut off from the
power supply.
Check the fuses.
Alarms have been released.
Check whether any alarms are signalled on the microprocessor control panel,
eliminate the causes and restart the unit.
The phase sequence is wrong.
Invert two phases in the primary power line after disconnecting them upstream from
the unit.
The
compressor is
noisy
The compressor is rotating in the
wrong direction. Check the phase sequence relay. Invert the phases on the terminal board after
disconnecting the unit and contact the manufacturer.
Presence of
abnormally
high pressure
Insufficient airflow through the
condenser.
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).
Presence of air in the refrigerant
circuit, as revealed by the presence of
bubbles in the flow indicator also with
sub-cooling values exceeding 5 °C. 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.
Unit overcharged, as revealed by a
Sub-cooling of more than 8 °C.
Drain the circuit.
Thermostatic valve and/or filter
obstructed. These symptoms may
also occur in the presence of an
abnormally low pressure.
Check the temperatures upstream and downstream from the valve and filter and
replace them if necessary.
Low
condensation
pressure
Transducer fault. Check the efficiency of the condensation control device (optional).
Low
evaporation
pressure
Malfunctioning of thermostatic valve.
Warming the bulb with your hand, check whether the valve opens and adjust it if
necessary. If it does not respond, replace it.
Filter dryer clogged.
Pressure drops upstream and downstream from the filter should not exceed 2°C. If
they do, replace the filter.
Low condensation temperature. Check the efficiency of the condensation control device (where present).
Low level of refrigerant.
Check the refrigerant level by measuring the degree of Sub-cooling; if it is below
2°C replenish the charge.
The
compressor
does not start
The internal thermal protection device
has tripped.
In the case of compressors equipped with a protection module, check the thermal
contact. Identify the causes after restarting.
The circuit breakers or line fuses have
been tripped by a short circuit. Pinpoint the cause by measuring the resistance of the individual windings and the
insulation from the casing before restoring power.
One of the HP or LP pressure
switches has tripped.
Check on the microprocessor, eliminate the causes.
The phases have been inverted in the
distribution compartment.
Check the phase sequence relay.
Air in the
cooling circuit
During external connections. Open the valve positioned on the right side over the top of the coil.
Water out from
the unit
The drain pan hole is closed.
Open the front panels, remove the sheet metal just below the e-panel (down flow
units) and clean it.
The siphon is missing. Check for the presence and provide for a new one.
The air flow is too high. Reduce the fan speed up to reaching the nominal air flow.