Systems for domestic - or space heating, in which heat is generated at one location and transmitted by a circuit to a consumer at a different location, of the following kind:

The heaters as such are covered by F24H, e.g. details concerning the heaters are covered in F24H 3/00.

Air-conditioning systems for cooling and heating are only covered by F24F.

Arrangements for protecting plants by heating, e.g. in gardens, are only covered by A01G 13/06.

Systems for space heating specially adapted for vehicles are covered by B60- B64.

The components of the heating system, e.g. heat sources or central heating radiators are also classified in other relevant groups:

Central heating systems comprising steam as heat transport medium and combinations thereof:

Constructional details of steam boilers are covered by F22B.

The special case of using steam or condensate extracted or exhausted from steam engine plants for heating purposes are covered by F01K 17/02.

Details of the steam central heating systems concerning drainage, venting, aerating or control are covered by the relevant subgroup in F24D 19/1003.

Hot-water central heating systems:

The hot-water central heating systems in this group do not comprise a storage mass for the central heating transfer fluid. Heating systems with a storage mass for the central heating transfer fluid are covered by F24D 11/00.

Hot-water central heating systems in combination with systems for domestic-hot water supply, where said domestic-hot water supply arrangements are located outside the boiler are covered by F24D 3/08. Devices with the domestic-hot water supply arrangements located within the boiler are covered by F24H 1/48.

Domestic hot water supply systems are covered by F24D 17/00.

Feed-line arrangements (filling valves, expansion tanks, pumps, distributors), which are exclusively used in hot-water central heating systems are classified in this group. An special case of feed-line arrangement concerning the connection of a water heater to circulation pipes is also covered by F24H 9/12.

Component, e.g. valves, pumps, etc, which are able to be used elsewhere are classified in the relevant subclass in F16K or F04.

Tube arrangements for ceiling, wall or underfloor heating, where the heating medium is hot-water are covered in F24D 3/12. Floorings in general are covered by E04F 15/00. Coverings or linings (walls, ceilings, etc) having conduits for fluids, in E04F 13/0869. The special use of the coverings or floorings for heating is covered by the group E04F 2290/023.

Electric underfloor heating is only covered by F24D 13/02.

Hot-water central heating systems in which additional heating means are located within the central heating radiators are covered by F24D 13/04.

Cooling ceilings are covered by F24F 5/00.

Heating floor for outdoor is covered by E01C 11/00.

Details of the hot-water central heating systems concerning drainage, venting, aerating or control are covered by the relevant subgroup in F24D 19/08.

Hot-air central heating systems:

Air conditioning systems heating and cooling air are classified only in F24F.

In the systems using a heat pump, the condenser is placed in the air channel for heating the air. There is no additional intermediate circuit between the cooling fluid of the heat pump and the air.

Arrangements with heat pumps heating a water circuit, said water circuit being used for heating air are covered in F24D 3/18.

Details of the control of hot-air central heating systems are covered by the relevant subgroup in F24D 19/1084.

Central heating systems employing heat-transfer fluids other than hot-water or hot-air, e.g. oil, salt, gas.

Systems with steam as heat-transfer are covered by F24D 1/00.

Central heating systems employing combinations of heat transfer fluids covered by two or more of the prior groups.

District heating systems with:

"District heating system" (less commonly called teleheating) is a system for distributing heat generated in a distant centralized location outside a building and distributed by means of a transfer fluid to multiple buildings or facilities. In the normal central heating systems, the heat source is located within the building.

District heating systems with heat accumulated in storage masses are covered by F24D 11/001.

Central heating systems using heat accumulated in storage masses, in particular:

The central heating systems in this group comprise a storage mass for the central heating transfer fluid. This storage mass can stay in the tank or be able to flow outside for being used. Details concerning tanks of the storage mass per se are covered by F24H 7/00. Details concerning water storage tanks with water being able to flow outside for being used are covered by F24H 1/18. Details of the tanks as such are covered by F28D 20/00

Details of storage heaters heating a fluid using a heat pump are also covered by F24H 4/04.

Storage masses in general are classified in the relevant subclasses, e.g. C04B.

Central heating systems using heat accumulated in storage masses using heat pumps are covered by F24D 11/02.

Arrangements of central heating systems in which a combination of more than one heat source is disclosed.

In particular, this class covers central heating systems without an storage mass recuperating waste heat source with a separate flue gas condenser.

The cases in which one of the heat sources is a heat pump are classified in other relevant subclasses.

Condensing boilers, in which the means adapted for extracting latent heat from the flue gases by means of condensation are located within the boiler are classified in F24H 8/00.

Cogeneration machines are classified in F02G.

Self-contained air heaters are classified in F24H 3/00.

Central heating radiators comprising additional heating means located within the radiator are covered by F24D 13/04.

Other domestic- or non-central space-heating systems, in particular:

Domestic hot-water supply systems using

Domestic hot-water supply systems comprising arrangements for preventing the occurrence or proliferation of microorganisms in the water

Domestic hot-water supply systems comprising recirculation systems.

Treatments of water for preventing the occurrence of microorganisms in general is covered by C02F 1/00. Devices for preventing the contamination of domestic plumbing installation are covered in E03C 1/00.

Hot-water central heating systems combined with systems for domestic hot water supply are covered by F24D 3/08.

Combined heat and power [CHP] generation systems, also known as cogeneration systems [CGS], which are specially adapted for heating of, or for supplying hot-water to, homes, offices and small buildings, i.e. systems providing both heat for heating fluids and electrical power.

A small-scale CHP system usually comprises the following units:

The small-scale CHP system can also optionally comprise:

Details concerning the heating system and the central heating radiators, in particular:

Details concerning the heater, i.e. the device generating the heat, as such are covered by F24H 9/00.

Central heating radiators as such are covered in F28D 1/00.

Arrangements for connecting heat exchanger in general to flow lines are covered by F28F 9/0246.

Arrangements for connecting different sections within a heat exchanger, e.g. radiators, are covered by F28F 9/26.

Mounting arrangements for special applications fixed on a central heating radiator are classified in the relevant subclass:

Arrangements for drainage, venting or aerating specially adapted for heating systems are covered in this group.

Draining valves or venting valves being used elsewhere are classified in the relevant subclass in F16K.

Arrangements for control of temperature and algorithm therefore are also covered by G05D 23/00.

Central heating radiators comprising additional heating means located within the radiator are covered by F24D 13/04.

Details of the control for heating systems are covered by the relevant subgroup in F24D 19/00.

Arrangements for connecting central heating radiators to circulation pipes are covered by F24D 19/0002. 

Devices for preventing or removing corrosion, slime or scale are covered by F24D 19/0092.

Arrangements of mounting or support for central heating radiators are covered by F24D 19/02.

Looping references between F24D 19/10 and F24H 9/20 have been identified. Until this inconsistency is resolved in IPC, the current classification practice in CPC is as follows: Please follow the limiting reference as it is in F24D 19/10. The limiting reference in F24H 9/20 is an informative reference.