BS 4856-2:1975

This standard BS 4856-2:1975 Methods for testing and rating fan coil units, unit heaters and unit coolers is classified in these ICS categories:

• 97.100.01 Heating appliances in general
• 91.140.30 Ventilation and air-conditioning systems

Part 2 of this British Standard deals with methods of carrying out thermal and volumetric tests of unit coolers without additional ducting. The unit coolers operate with or without condensation on the coils. The unit coolers are of the type used for cooling and dehumidifying purposes under frost-free conditions of operation. The cooling medium used is water or other heat transfer fluid (excluding volatile refrigerants). The range of approximate air volume flow rates is between 25 × 10^–3 m³/s and 5 m₃/s.

The tests are to be carried out on units in an essentially clean condition.

This standard applies to units having operating temperatures of primary fluid within the range 0 °C to 27 °C.

The primary fluids used are; water, brine, glycol, heat transfer fluid.

The minimum temperature differential (see 14.2) of the primary fluid under test is 3 °C.

There is no restriction on the mounting of these units for testing provided that they are tested whilst mounted in a way representative of their intended use.

The standard specifies performance characteristics that are to be obtained from a unit. Although the requirements of the methods for individual tests may be followed to determine the performance of a unit at one specified set of conditions, where the performance at conditions other than those of the actual test are to be stated the full schedule of tests specified in the standard have to be made.

Coolers as used for cooling and dehumidifying under frost-free conditions, the medium used being water or other heat transfer fluid (excluding volatile refrigerants).