@DNOVA THS_R410A-IOM-1304-E
22
9
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. 7
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 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.
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.
Unit is not perfectly level
Place correctly the unit.
