Rev. F 02-2021
12
MTEC.6400.GB-F-1 Operation and maintenance manual HDA series English
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3.1 Unit description
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controlled or water vapor condensation should be prevented. These units are particularly indicated for archives, ironing rooms, bookstores,
cheese factories, underground rooms, cellars and industrial sites where high humidity level is present. This series comprises 5 models
which cover a capacity range from 73 to 240 l/24h. The units are designed for easy maintenance and service, each part being readily ac-
cessible and, when required, easily replaceable thus reducing service and maintenance costs. The units are supplied with a solenoid valves
set for the hot ga s injection used to defrost the evaporator in case of severe working conditions.
3.1.1 Frame
All units are made from hot-galvanised thick sheet metal, painted with polyurethane powder enamel at 180°C to ensure the best resistance
against the atmospheric agents. The frame is self-supporting with removable panels. All screws and rivets are in stainless steel. The colour
of the units is RAL 9018.
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The refrigerant gas used in these units is R410A. The refrigerant circuit is made by using international primary brands components and ac-
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external equalizer, Schrader valves form maintenance and control, pressure safety device (according to PED regulation). All the units are
supplied with injection valves kit for hot gas defrost cycle.
3.1.3 Compressors
The compressors are rotative type, with thermal overload protection by a klixon embedded in the motor winding. The compressor is mount-
ed on rubber vibration dampers and it is supplied,standard, with sound-proof cover to reduce noise emission. The inspection is possible
through the frontal panel of the unit that allows the maintenance of the compressor.
3.1.4 Condenser and evaporator
Condensers
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All evaporators are painted with epoxy powders to prevent corrosion problem due to their use in aggressive environments. The diameter of
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to improve the heat exchange factor. The geometry of these heat exchangers guarantees a low air side pressure drop and then the use of
low rotation (and low noise emission) fans. All units are supplied, standard, with a stainless steel drip tray and all evaporators are supplied
with a temperature sensor used as automatic defrost probe.
3.1.5 Supply fan
The fans are made of galvanized steel, centrifugal type. It is statically and dynamically balanced and supplied. The electric motors are
directly connected to the fan; they are all at 3 speeds, with integrated thermal protection. The protection class of the motors is IP 54.
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class M5, according to EN 779:2012.
3.1.7 Microprocessors
All units are supplied standard with microprocessor controls. The microprocessor controls the following functions: compressor timing, auto-
matic defrost cycles, alarms. An appropriate LCD display shows the operation mode of the unit, set point and alarms.
3.1.8 Electric enclosure
The electric switch board is made according to electromagnetic compatibility norms CEE 73/23 and 89/336. The accessibility to the board is
possible after removing the front panel of the unit and the OFF positioning of the main switch. The following components are also standard
installed: main switch, magnetic-thermal switches (as a protection fans and compressors), control circuit automatic breakers, compressor
contactors, fan contactors. The terminal board is supplied with voltage free contacts for remote ON-OFF and general alarm.
3.1.9 Control and protection devices
All units are supplied with the following control and protection devices: antifreeze protection sensor, high pressure switch with manual
reset, low pressure switch with automatic reset, high pressure safety valve, compressor thermal overload protection, fans thermal overload
protection.
3. TECHNICAL CHARACTERISTICS
