CombiSteel 7480 Serie Mode D'emploi page 12

9-10 Switchboard heater
It is an optional accessory that is required when the unit has to be installed in a place with a very harsh climate
(temperature below -10°C for long periods); it serves to maintain inside the switchboard, where it is installed,
the right temperature for the correct functioning of the electric components. This device is provided with an
inner temperature regulator.
9-11 Defrost solenoid valve
It is installed on all units, except the High temperature ones and all Split and Bi Block series. It opens, every time
a defrost is requested. In the units up to form 3, hot gas used for the defrost passes directly through the solenoid
valve. In the bigger units the solenoid valve operates the deflection valve (9-12) that controls the gas passage.
The solenoid valve closes again at the end of the defrost.
9-12 Defrost deflection valve
It is on the Wall-mounting units, forms 4 and 5 except the High temperature ones and it serves to deflect the hot
gas flow from the condenser to the evaporator to execute the defrost. To work it has to be controlled by a
solenoid valve (9-11).
9-13 Non-return valve of the defrost line
It is installed on the Wall-mounting units, forms 4 and 5 except the High temperature ones and it lies on the pipe
of the defrost line at the entrance of the evaporator. It serves to prevent the liquid formed in the evaporator
from flowing back along the defrost line, at the end of the defrost.
9-14 Defrost heaters
They lie on the evaporator of all the Split and Bi Block units, except the High temperature ones, ranges and they
are used to heat the evaporating battery during the defrost.
9-15 Drain heater
It is set inside the evaporator drainpipe. It is present on all medium and low temperature units. In the units with
defrost by hot gas, it is controlled by the main switch (when the unit is on, the heater is always working), whereas
in the Split and Bi Block units it is electrically connected with the defrost heaters. It is used to discharge the water
produced during the defrost, in order to prevent the water freezing inside the drainpipe.
9-16 Crankcase heater
It is standard installed on the compressors of the Wall-mounting and Bi Block units forms 4 and 5; it is used to
heat the crankcase before the starting and to keep it hot during the compressor stop.
The heat produced by the heater causes the evaporation of the eventual liquid-state refrigerant that is inside the
compressor: in this way the compressor starting stress is reduced and, above all, the valve breaking is avoided,
which otherwise could be a consequence of the liquid compression.
It is indispensable when the unit is installed in places with low temperature.
The heater works manually when the unit is connected with the supply line and the main switch is in position
"OFF", or it starts up automatically when the unit is executing the refrigerating process.
12
www.combisteel.com