NEN EN 621 : 2009

Foreword
1 Scope
2 Normative references
3 Definitions
    3.1 Appliance and its constituent parts
    3.2 Adjusting, control and safety devices
    3.3 Operation of the appliance
    3.4 Gases
    3.5 Conditions of operation and measurement
    3.6 Marking of the appliance and packaging
    3.7 Classification
          3.7.1 Classification of gases
          3.7.2 Classification of appliance
4 Construction and design requirements
    4.1 General
          4.1.1 Conversion to different gases
          4.1.2 Materials and method of construction
          4.1.3 Accessibility for maintenance and use
          4.1.4 Thermal insulation
          4.1.5 Gas connection
          4.1.6 Soundness
          4.1.7 Supply of combustion air and evacuation of
                  combustion products
          4.1.8 Supply and distribution of air for space
                  heating
          4.1.9 Position of the combustion chamber and heat
                  exchanger
          4.1.10 Checking the state of operation
          4.1.11 Electrical equipment
          4.1.12 Operational safety in the event of
                  fluctuation, interruption and restoration of
                  the auxiliary energy
          4.1.13 Motors and fans
    4.2 Adjusting, control and safety devices
          4.2.1 General
          4.2.2 Gas rate adjusters and range-rating devices
          4.2.3 Aeration adjusters
          4.2.4 Manual controls
          4.2.5 Governors
          4.2.6 Multifunctional controls
          4.2.7 Flame supervision devices
          4.2.8 Automatic shut-off valves
          4.2.9 Automatic burner control systems
          4.2.10 Gas strainers
    4.3 Ignition devices
          4.3.1 General
          4.3.2 Ignition device for the main burner
          4.3.3 Ignition burners
    4.4 Flame supervision system
          4.4.1 Non-automatic burner systems
          4.4.2 Automatic burner systems
    4.5 Start-gas flame establishment
          4.5.1 Non-automatic burner systems
          4.5.2 Automatic burner systems
    4.6 Main flame establishment
          4.6.1 Establishment by means of a start-gas flame
          4.6.2 Direct establishment of the main flame, e.g.
                  spark ignition, hot surface igniter
    4.7 Main burner
    4.8 Facility for remote control
    4.9 Thermostats and control of air temperature
          4.9.1 General requirements
          4.9.2 Overheat cut-off device
          4.9.3 Overheat control device
          4.9.4 Overheat cut-off/control devices
          4.9.5 Fan delay controls
          4.9.6 Sensors
    4.10 Gas pressure test points
    4.11 Combustion chamber pressure relief
    4.12 Facilities for commissioning and testing
5 Operational requirements
    5.1 Safety of operation
          5.1.1 Soundness
          5.1.2 Heat inputs
          5.1.3 Limiting temperatures
          5.1.4 Ignition, cross-lighting, flame stability
          5.1.5 Combustion
          5.1.6 Overheat cut-off device
          5.1.7 Heat exchanger thermal cycling
    5.2 Efficiency
6 Test methods
    6.1 General
          6.1.1 Characteristics of test gases: reference and
                  limit gases
          6.1.2 Conditions for preparation of the test gases
          6.1.3 Practical application of test gases
          6.1.4 Test pressures
          6.1.5 Test procedures
          6.1.6 General test conditions
    6.2 Construction and design
          6.2.1 Automatic burner control systems (manually
                  operated devices)
          6.2.2 Ignition opening time
          6.2.3 Extinction safety time
          6.2.4 Safety time
    6.3 Safety of operation
          6.3.1 Soundness
          6.3.2 Heat inputs
          6.3.3 Limiting temperatures
          6.3.4 Ignition, cross-lighting, flame stability
          6.3.5 Combustion
          6.3.6 Overheat cut-off device
          6.3.7 Heat exchanger thermal cycling
    6.4 Efficiency
          6.4.1 General conditions of test
          6.4.2 Test conditions
          6.4.3 Test procedure
          6.4.4 Accuracy of measurement
          6.4.5 Calculation of efficiency
          6.4.6 Supplementary test for appliances with a
                  modulating or high/low control
7 Marking and instructions
    7.1 Marking of the appliance
          7.1.1 Description
          7.1.2 Data plate
          7.1.3 Other marking
    7.2 Marking of the packaging
    7.3 Utilization of symbols on the appliance and packaging
          7.3.1 Electrical supply
          7.3.2 Type of gas
          7.3.3 Gas supply pressure
          7.3.4 Country of destination
          7.3.5 Category
          7.3.6 Other information
    7.4 Instructions
          7.4.1 General
          7.4.2 Technical instructions for installation and
                  adjustment
          7.4.3 Instructions for use and maintenance
Annex A (informative) National situations
Annex B (informative) Equivalence rules
Annex C (normative) Requirements for high-voltage ignition
           circuits
Annex D (informative) Facilities with automatic ignition
Annex E (informative) Means of identification of the various
           types of gas in force in the various countries
Annex F (informative) A-deviations
Annex G (normative) Special national conditions
Annex ZA (informative) Clauses of this European Standard
           addressing requirements or provisions of EU
           Directives

Defines the requirements and test methods for the safety and efficiency of non-domestic gas-fired air heaters not exceeding a net heat input of 300 kW with (an) atmospheric burner(s) and without a fan to assist the transportation of combustion air and/or flue gases, hereafter referred to as 'appliances'.