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Accorroni MEC25-85 Technical Information

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Gas-fired air heaters
MEC 25÷85
MEC 35÷85 C

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Summary of Contents for Accorroni MEC25-85

  • Page 1 Gas-fired air heaters MEC 25÷85 MEC 35÷85 C...

  • Page 3: Table Of Contents

    A2B Accorroni E.G. S.r.l. in any way with regard to others. 6 - A2B Accorroni E.G. S.r.l. is responsible for ensuring that its product conforms to the laws, directives and construction standards in force at the time the product is sold. Knowledge and compliance with legal regulations and standards regarding plant design, installation, operation and maintenance are the exclusive responsibility, for the respective competencies, of the designer, installer and user.
  • Page 4 CONTROL AND SAFETY DEVICES ..................19 Control device ........................19 Gas unit ..........................19 Differential pressure switch ....................19 Fan thermostat ........................20 Safety thermostat ........................20 SECTION 2 - TECHNICAL INFORMATION FOR THE INSTALLER PRECAUTIONS ........................21 Gas Safety Regulations ......................21 Related documents ........................
  • Page 5 11.4 Shutdown ..........................39 11.5 Summer ventilation ........................ 40 PLANT MAINTENANCE ......................40 12.1 Routine maintenance to be performed by the user ..............40 12.2 Annual air heater inspection ....................40 FIGURE SUMMARY Fig. no............................page Dimensions ............... - MEC 25 - 30 - 35 ......7 Dimensions ...............

  • Page 6: Principal Characteristics

    SECTION 1 - GENERAL INFORMATION 1. PRINCIPAL CHARACTERISTICS certificate” in conformity with EEC Directive 90/ 396 and with reference to the harmonised 1.1 APPLIANCE CLASSIFICATION European standard prEN 1020. Attaching the CE These appliance are defined as “Gas-fired air marking shown below also guarantees that the heaters with an atmospheric burner equipped appliance conforms with EEC directive 73/23 with a fan in the combustion circuit”.

  • Page 7: Construction Characteristics

    control panel the air heater can be used, during 1.5 PACKAGE CONTENTS the summer, just to ventilate the room, excluding The air heater is shipped with cardboard packing the burner operation. and internal protective pieces in pre-formed 1.4 CONSTRUCTION CHARACTERISTICS cardboard.
  • Page 8 1.7 FIELDS OF USE applied to the air intake (in fact, centrifugal fans are needed due to the load losses induced by MEC and MEC C air heaters can be used to build that filter) and/or a change is required with modular plants, consisting of one or more outdoor air, to be conveyed by ducts.

  • Page 9: Dimensions

    1.8 DIMENSIONS - MEC series with axial fans - Models 25 - 30 - 35 Exhaust outlet Air inlet Gas inlet Fig. 1 ISO 7/1 R 1/2 Flue gas Gas Ø140 Ø 80 R 1/2" page 7...
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  • Page 12: Dimensions

    1.9 DIMENSIONS - MEC C series with centrifugal fans - Models 25 - 30 - 35 Exhaust outlet Air inlet Gas inlet ISO 7/1 R 1/2 Fig. 4 Flue gas Gas Ø140 Ø 80 R 1/2" page 10...
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  • Page 18 Parts legend 1 Atmospheric burner 2 Burner insulating gasket 3 Gas injectors 4 Ignition electrode 5 Flame detection electrode 6 Second ignition transformer (model 85) 7 Complete gas unit 8 “T” gas fitting (model 85) 9 Gas supply pipe for 2nd burner (model 85) 10 Control device 11 Printed circuit board 12 Radio interference filter...
  • Page 19 1.11 WIRING DIAGRAM MEC 35-35C-57-57C-85-85C [g/ v] [ n] = blue Cable colors [bi] = white J26 J25 = yellow [g/v] = yellow/green [gr] = grey ELECTRICAL SCHEMA FOR AXIAL FAN = brown = black 1a N N 1a N 1a SB RS [b] common [n] common...
  • Page 20 1.11 WIRING DIAGRAM MEC 25 [g/ v] [ n] J26 J25 ELECTRICAL SCHEMA FOR AXIAL FAN 1a N N 1a N 1a SB RS L M M 1 2 3 4 5 6 common condenser Mve1 max. = blue Cable colors [bi] = white = yellow...

  • Page 21: Wiring Diagram

    1.11 WIRING DIAGRAM MEC 50 [g/ v] [ n] = blue Cable colors [bi] = white J26 J25 = yellow [g/v] = yellow/green [gr] = grey ELECTRICAL SCHEMA FOR AXIAL FAN = brown = black 1a N N 1a N 1a SB RS L M M 1 2 3 4 5 6 common...

  • Page 22: Technical Data Table

    1.12 TECHNICAL DATA TABLE Units Heat input (H 25,0 30,0 34,8 50,0 57,0 85,0 kcal/h 21.500 25.800 29.900 43.000 49.000 73.100 Heat output (H 22,9 27,5 31,9 45,3 51,6 75,6 kcal/h 19.700 23.650 27.400 38.960 44.380 65.050 Natural gas G20 2,65 3,17 3,70...

  • Page 23: Control And Safety Devices

    2. CONTROL AND SAFETY DEVICES 2.2 GAS UNIT The gas unit includes two, direct operation solenoid 2.1 CONTROL DEVICE valves with class B closing devices (maximum This device is housed in a heat-resistant and pressure 60 mbar) and a pressure regulator. The shockproof plastic enclosure and is mounted on die-cast aluminium casing is equipped with 1/2 the air heater electric board, inside the service...

  • Page 24: Fan Thermostat

    The pressure switch is mounted on the air heater 2.5 SAFETY THERMOSTAT electric board and is connected by a silicon tube The thermostat is designed to interrupt burner to a pressure fitting on the exchanger to detect the operation when the air temperature in the air differential pressure on the combustion circuit.

  • Page 25: Section 2 - Technical Information For The Installer

    SECTION 2 - TECHNICAL INFORMATION FOR THE INSTALLER 3. PRECAUTIONS 3.4 DATA CHECK Check that the air heater and its technical 3.1 GAS SAFETY (Installation and Use) characteristics match what is indicated by the (Amendment) REGULATIONS 1990 design or other documents. The law requires all gas appliances to be The type of gas for which the air heater has installed by competent persons in accordance...

  • Page 26: Minimum Heights And Distances

    4.1.1 Installation of MEC air heaters for the to consider the working environment and the air free delivery of warm air temperatures which will result when the overheat limit thermostat is being commissioned. Where To ensure the optimal configuration of the air inter-joist spaces are used as duct routes, they heaters within an environment, it is recommended should be suitably lined with a fire-resisting...

  • Page 27: Air Intake And Flue Exhaust Ducts

    When installing MEC C ducted air heaters, it heater. Therefore, they must be requested should be recalled that, to perform from A2B Accorroni E.G. S.r.l., together with maintenance, there must be free access to the appliance. the front of the exchanger which contains...

  • Page 28: Type C Installation

    Minimum Type C 20 cm The combustion circuit is hermetically sealed with respect to the environment. The ducts pass directly through the outside wall of the room, with terminals 8 cm close to each other. Top view Side view Fig. 19 Type C The combustion circuit is hermetically sealed with...

  • Page 29: Installation Operations

    - Type B Length (cm) Min. Max. Exhaust only The combustion circuit is not hermetically sealed (Type B with respect to the environment in which the air heater is installed. Combustion air intake is Exhaust + intake performed within the environment, while the (Types C 2 x 50 2 x 300...

  • Page 30: Start-Up

    to be used as a general switch to turn off the 4.4.7 Connecting more than one unit with a appliance. single timer Insert the power supply cable through the special To operate several appliances with just one timer cable gland, making sure to cut the wires so that follow the diagram reported in fig.

  • Page 31: Ignition

    5.1.4 Check that the gas on-off valves on the At this point the pre-ventilation phase begins, meter and near the air heater are open. Make sure starting the flue exhaust fan which, when operating that the air inside the gas supply piping has been correctly, closes the differential pressure switch bled off.

  • Page 32: Useful Information

    WARNING! When the burner turns off, the 6. GAS TYPE CHANGE fan(s) will continue to operate for a few WARNING! The operations described below minutes, to properly cool the exchanger. must be carried out by skilled technical Therefore, it is important not to turn off the air personnel.

  • Page 33: Switching From Gas In The Third Group To Gas In The Second Group

    the new seal washers and completely tighten particular attention on the burner and gas unit to guarantee a proper gas seal (fig. 27) pressure inlets. f) (only for models 50 - 57) unscrew the gas 6.2 SWITCHING FROM GAS IN THE THIRD fitting on the burner, remove the gasket and GROUP (G30 - G31) TO GAS IN THE replace it with the calibrated diaphragm.

  • Page 34: Operating Defects

    e) screw the new injectors into place, inserting m)use a special spray or electronic leak detector the new aluminium seal washers and completely to identify any leaks in the gas circuit, with tighten to guarantee a proper gas seal (fig. 27) particular attention on the burner and gas unit pressure inlets.
  • Page 35 d) the flue exhaust fan motor is malfunctioning conditions, condensate may form which, if and the differential pressure switch does not present inside the silicon tube, and even just issue the enabling signal to start the cycle. a few drops, might prevent the pressure switch from performing the measurement.
  • Page 36 marked as “L” and “N” and reversing the occurred due to incorrect operation of the fan polarity may de-activate the flame detection control thermostat. device. - Replace the control thermostat of the fan(s) - Check using a multimeter or phase detector (see point 8.5).

  • Page 37: Replacing Parts

    8. REPLACING PARTS GAS UNIT COIL REPLACEMENT Models 25 - 30 - 35 Since specific technical skills are required to replace the parts listed below, it is Coil cage Gas unit recommended to advise the user to always contact skilled technical personnel. For safety and quality reasons, it is recommended to use original spare parts when replacing components.

  • Page 38: Control Thermostat Of The Convection Fan(S)

    PRESSURE SWITCH REPLACEMENT SAFETY THERMOSTAT REPLACEMENT Electrical connection Sensor support Silicon tube Thermostat enclosure Thermostat Fastening screws sensor Fig. 31 Fig. 33 WARNING! The calibration of the new is not greater than 3 mm, to guarantee that the differential pressure switch must correspond sensor remains in contact with the wall of the to the appliance model on which it is replaced.

  • Page 39: Electrodes

    ELECTRODE POSITIONING IGNITION TRANSFORMER Models 50 - 57 Model 85 only (second burner) Correct distance 3 mm Ignition electrode between electrode cable and burner Electrical connections Detection electrode Ignition electrode Fig. 35 Fig. 37 8.7 ELECTRODES ignition electrode, open the service door on the left of the appliance.

  • Page 40: Flue Exhaust Fan

    the fittings. In the rear of the appliance, FLUE EXHAUST REPLACEMENT corresponding to the fitting with the flue exhaust Model 85 duct, unscrew the four fan scroll fastening screws. Stainless Extract the unit, being careful not to damage the steel ducts gasket between the fan scroll and the rear panel Duct of the air heater.

  • Page 41: Periodic Maintenance Operations

    8.10.2 MEC C series centrifugal fan 9. PERIODIC MAINTENANCE OPERATION Disconnect the fan electrical connection from the 9.1 USER INFORMATION terminal strip on the printed circuit board of the air It is recommended to advise the user to carry out heater electric panel.

  • Page 42: Health And Safety Statement

    10. HEALTH AND 10.5 ELECTROLYTIC CAPACITOR SAFETY STATEMENT Two types are used by random selection: Recognition: 1. Plastic enclosure 10.1 GENERAL 2. Aluminium enclosure Under the 1987 Consumer Protection Act and Material: Contained liquid electrolyte Section 6 of the 1974 Health and Safety at Work Known hazards: Electric shock possible if Act, we hereby provide the following information charged.

  • Page 43: Section 3 - User Operating And Maintenance Instructions

    SECTION 3 - USER OPERATING AND MAINTENANCE INSTRUCTIONS 11. START-UP - appliance with room thermostat: set the thermostat regulation device to the 11.1 FIRST FIRING AND TESTING highest value WARNING! It should be recalled that the first After this operation, the appliance starts working firing of the appliance and the relative tests and, after about three minutes from when the must be performed by skilled technical...

  • Page 44: Summer Ventilation

    b) after the fan(s) have turned off, disconnect the WARNING! The operations described in points electric power supply at the mains switch a) b) and c) below must be performed while the air heater is not functioning, excluding c) close the gas on-off valve the gas and electric supplies.
  • Page 48 A2B Accorroni E.G. S.r.l. - Via d’Ancona, 37 - 60027 Osimo (An) Tel. 071.723991 - Fax 071.7133153 - Web Site: www.accorroni.it - E-mail: a2b@a-2-b.it...

This manual is also suitable for:

Mec35-85c

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