UTEK HRU, Manual For Installation, Use And Maintenance

Page: 35 / 39

35
TROUBLESHOOTING
PROBLEM OPERATING MODE CAUSE CORRECTIVE ACTION
COOL. HEAT.
A) THE UNIT DOE S NOT
START OR DOESN'T START
VERY EASILY
Faulty connection or
open contacts.
Check the voltage and close the contacts.
The service thermostat
does not issue the
acknowledgement.
Check the calibration and operation.
The anti -frost thermostat
does not issue the
acknowledgement.
Check the calibration and operation.
The fan thermal switches
have tripped.
See point F.
The safety device does
not issue the
acknowledgement.
See points D -E.
Faulty compressor. See point B.
The cyclic rotation of
phases is incorrect. Check the cyclic sequence of phases, and
reverse the power supply phases.
Low supply voltage. Check the nameplate data.
Insufficient fan torque.
Adjust the shutters of the ventilation circuit
until you reach the full speed. If necessary,
replac e the fan motor.
B) THE COMPRESSOR
DOES NOT START
Burnt or seized
compressor.
Replace the compressor.
De-energized
compressor contactors. Check the voltage on the terminations of the
coil and the continuity of the coil.
Open power circuit –
Er10.
Search for the reason that has caused the
coil to trip.
Pressure switches
energized – Er01, Er05. Manually reset the high pressure switch; the
low pressure switch resets
automatically.
Incorrect cyclic sequence
of phases. Check the cyclic sequence of phases and
reverse the supply phases.
C) THE COMPRESSOR
STARTS AND STOPS
REPEATEDLY Pressure switch for
minimum pressure
tripped.
See point E.
Faulty compressor
contactors.
Check the contactors and replace it required.
Faulty compressor.
Check the compressor and replace it.
See point B.
No coolant. See point G.
D) THE COMPRESSOR
DOES NOT START
BECAUSE THE HIGH
PRESSURE SWITCH IS
ACTIVATED Faulty pressure switch Check the pressure switch and replace it.
Too much coolant. Discharge the gas in excess.
Clogged suction air filters
– E r56 . The air flow rate
is too low.
Clean the filters with compressed air and
replace them if necessary.
The condenser fan is not
working.
See point F.
The condenser fan runs
in opposite direction.
Check the direction of rotation of the phases.
Non condensing gases in
cooling circuit. Reload the circuit after discharging it and
running the vacuum cycle.
Clogged coolant filter. Check the filter and replace it.