EN 835:1994

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 K[o]
   7.3 Rating factor K[c]
   7.4 c-value
   7.5 Rating factor K[t]
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 hygroscopicity
   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 K[o]
   10.13 Rating factor K[c]
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

Heat cost allocators in accordance with this standard are instruments for the registration of the heat output of radiators in consumer units. Consumer units are dwellings, office buildings, business premises, industrial plants in which the heat is supplied by a common central heating systems or by a common district heating connection. A complete grouping of consumer units is called an account unit.