NEN EN 835 : 1994

Committees responsible
National foreword
Foreword
1. Introduction
2. Scope and general terms
3. Functional principle
4. Definitions
4.1 Reference condition
4.2 Reference temperature of the measuring liquid
4.3 Design flow and return temperatures, mean design
      heating medium temperature, design temperature
      of the measuring liquid
4.4 Displayed reading
4.5 Rated displayed reading
4.6 Nominal evaporation
4.7 Evaporation rate
4.8 Counting rate
4.9 Meter characteristic
4.10 Counting ratio
4.11 Consumption scale
4.12 Unit scale
4.13 Idle evaporation
4.14 Measuring period
4.15 c-value
4.16 Rating factors
4.17 Manufacturer
5. Requirements for heat cost allocators
5.1 Casing
5.2 Ampoule
5.3 Measuring liquid
5.4 Over-fill for idle evaporation
5.5 Sealing
5.6 Scale system
5.7 Consumption scale
5.8 Unit scale
6. Requirements for use and installation
6.1 Temperature limits
6.2 Installation on the radiator
6.3 Installation position
6.4 Conformity of instruments
6.5 Requirements for installation in single pipe systems
7. Requirements for rating
7.1 Resulting rating factor K
7.2 Rating factor KQ
7.3 Rating factor KC
7.4 c-value
7.5 Rating factor KT
8. Requirements for maintenance and reading
9. Testing
9.1 General
9.2 Test documents
9.3 Test report
9.4 Test protocols
10. Test procedures
10.1 Construction
10.2 Sealing
10.3 Thermal durability
10.4 Ampoule
10.5 Measuring liquid purity and risk to health
10.6 Measuring liquid meter characteristics and hygro-
      scopicity
10.7 Upper temperature limit
10.8 Measuring liquid over-fill for idle evaporation
10.9 Scale system
10.10 c-value, test procedure
10.11 c-value, test range
10.12 Rating factor KQ
10.13 Rating factor KC
11. Marking
Annex A (informative) Information and recommendations
A.1 Heating systems
A.2 Recommended field of application
A.3 Heat emission not controllable by the consumer
A.4 Additional corrections
Annex B (informative) Bibliography

Defines heat cost allocators without electrical power supply, based on the evaporation principle, which help to establish the consumption value of a room radiator. Also specifies the minimum requirements for materials, construction, installation, production, function and evaluation of the displayed readings established by the measuring devices.