Troubleshooting - Techno Block UT 1 Notice De Mode D'emploi Et D'entretien

12.3 Troubleshooting

During operation the following troubles may occur:
1. The unit does not operate perfectly.
Check the refrigerating gas on the specially-fitted indicator available on all units fitted with a thermostat
(check when the unit is operating and the cold room temperature is closed to the required value). Normally the
indicator is clear; in the absence of gas, gas bubbles will appear.
2. Compressor or fans have stopped working.
- Check fuses protecting the main and auxiliary circuits. Should they have been activated, replace them
making sure that supply voltage and phase polarity are correct.
- If the compressor is in cutout state, reset the overload relay manually after identifying the causes of the
trouble.
- If motor fan stops working, it can be restarted automatically, but the cause of the trouble should be
identified. Check compressor/fan overtemperature devices inside the electric panel. Switch off mains switch
before operating on same.
3. Unsatisfactory efficiency of the unit
If the unit does not perform adequately and no defects can be identified, check that: cold room doors are
perfectly tight; no cold dispersion is available; the cold room is used wisely; no unfrozen liquids or foodstuffs are
placed in the low temperature room; the evaporator is ice-free.
We advise to install the units far from the doors, especially when the cold room is expected to be opened many
times a day.
WARNING:
Removal of protections during machine operation is absolutely forbidden. They have been
developed to safeguard the operator's safety.
4. Other troubles may be due to the triggering of the following electrical safety devices:
a) Compressor overload relay - manual reset
This relay protects the compressor from high power absorption due to :
- lack of a phase
- excessive condensation pressure, resulting from too high temperature in the cold room
- dirty condenser or fan not working
- ice in the evaporator
After eliminating the cause, reset the overload relay manually.
b) Fan thermal protection (incorporated in the motor) - automatic reset
It protects electric fans against high power absorption due to:
- overheating
- lack of a phase (only for three-phase models)
- dirty condenser
- ice in the evaporator
c) High pressure switch - automatic reset
It protects the compressor from excessive pressures (which cause the pressure switch to be triggered very
often) due to:
- dirty condenser
- non-operating condenser fans
- excessive temperature in the room where the unit is installed
- unit used in unsuitable conditions or with inappropriate products.
d) Low pressure switch - automatic reset
This device is activated every time the unit stops when reaching the right temperature.
It can also be triggered in case of excessively low pressures compared with the set values. This can be due to:
- lack of gas due to tube breakage or loosened unions
- clogged filters
- broken solenoid valve
- ice in the evaporator
Min. and max. pressure switches are placed in motor room. Before resetting, disconnect mains switch.
e) Thermistors - automatic reset
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work on the control panel, ON/OFF and emergency switches
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work on protection and safety devices.
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