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DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR (preventing corrosion C23F; water supply in general E03; using steam or condensate extracted or exhausted from steam engine plants for heating purposes F01K 17/02 ; steam traps F16T; domestic stoves or ranges F24B, C; water or air heaters having heat generating means F24H; combined heating and refrigeration systems F25B; heat exchange apparatus or elements F28; removing furring F28G)
Definition statement
This subclass/group covers:

Domestic- or space-hating systems of the following kind:

  • Steam central heating systems
  • Hot-water central heating systems
  • Hot-air central heating systems
  • Central heating systems employing heat-transfer fluids not being hot-water or hot-air, e.g. oil, salt, gas
  • Central heating systems employing combinations of two or more of the above-mentioned heat transfer fluids
  • District heating systems
  • Central heating systems using heat accumulated in storage masses
  • Other central heating systems
  • Electric heating systems (central heating or domestic heating)
  • Other domestic- or non-central space-heating systems
  • Domestic hot-water supply systems
  • Details thereof, including constructional details and control means for heating systems
Relationship between large subject matter areas

Subclass F24D covers 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.

The heaters as such are covered by F24H.

Air-conditioning systems able 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 adapted for vehicles are covered by B60 to B64.

Details concerning the heaters as such are covered in F24H 3/00.

Domestic stoves or ranges are covered by F24B and F24C.

Combined heating and refrigeration systems are covered by F25B.

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

  • burners in F23B
  • arrangements for feeding fuel to burner in F23K
  • air supply, air draught for burner in F23L
  • electric heating means in H05B
  • heat pumps in F25B
  • solar collector or geothermal systems in F24J
  • heat exchangers in F28
  • valves in F16K
  • pumps F04
  • water supply and sewerage in E03B and E03C
  • arrangements for controlling temperature in G05D 23/00.
References relevant to classification in this subclass
This subclass/group does not cover:
Arrangements for protecting plants by heating , e.g. in gardens
Baking ovens
Cooking devices other than ranges
Domestic stoves
Air-conditioning systems able for cooling and heating
Systems of space heating adapted for vehicles
Informative references
Attention is drawn to the following places, which may be of interest for search:
Water supply, sewerage
E03
Using steam or condensate extracted or exhausted from steam engine plants
Pumps
F04
Valves
Combustion apparatus in general
F23
Heaters having heat generating means
Apparatus using heat produced by solar, geothermal or other external chemical reaction other than combustion
Heat pumps
Heat exchangers, in particular central heating radiators
F28
Heat storage plants
Electric heating elements as such
Arrangements for controlling temperature
Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
Central heating system
a system in which heat is generated or stored at central sources inside a building and is distributed by means of a transfer fluid to the spaces or areas to be heated within the building
District heating system (less commonly called teleheating)
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
Domestic hot water heating system
a system for heating tap water coming from the main water supply for domestic use other than space heating, e.g. cooking, cleaning, bathing
Steam central heating systems (F24D 10/00, F24D 11/00 take precedence)
Definition statement
This subclass/group covers:

Steam central heating systems:

  • in combination with systems for domestic water supply
  • operating with live steam (i.e. steam produced for heating)
  • operating with exhaust steam (i.e. exhaust steam of a generating power plant being used for heating)
  • operating with superheated steam
  • feed-line arrangements thereof.
Relationship between large subject matter areas

This group cover central heating systems comprising steam as heat transport medium.

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.

References relevant to classification in this group
This subclass/group does not cover:
Steam engine plants as such
Steam generation, steam boilers
District heating systems
Central heating systems using heat accumulated in storage masses
Informative references
Attention is drawn to the following places, which may be of interest for search:
Pump having characteristics not provided elsewhere
The special case of using steam or condensate extracted or exhausted from steam engine plants for heating purposes extracted or exhausted from steam engine plants for heating purposes
Details concerning the heat exchanger
Venting, aeration arrangements for steam heating systems
Arrangements or mounting of control or safety devices for steam heating systems
Hot-water central heating systems (F24D 10/00, F24D 11/00 take precedence)
Definition statement
This subclass/group covers:

Hot-water central heating systems:

  • combined with solar energy
  • with forced circulation, e.g. by pumps
  • with the water under high pressure
  • in combination with systems for domestic hot-water supply
  • arrangements for feeding water into the system
  • tube and panel arrangements for ceiling, wall, or underfloor heating
  • using heat pumps.
Relationship between large subject matter areas

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.

References relevant to classification in this group
This subclass/group does not cover:
District heating systems
Central heating systems using heat accumulated in storage masses
Informative references
Attention is drawn to the following places, which may be of interest for search:
Heating floor for outdoor
Plumbing installations for fresh water
Floor construction with regard to insulation, Connections specially adapted therefore
Special adaptations of floors for incorporating ducts, e.g. for heating or ventilating
Ceilings, Construction of ceilings, e.g. false ceilings, Ceiling construction with regard to insulation
Building elements of block or other shape for the construction of parts of buildings characterised by special adaptations, e.g. serving for locating conduits
Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels
Building elements of relatively thin form for the construction of parts of buildings with special adaptations for auxiliary purposes, e.g. serving for locating conduits
Coverings or linings (walls, ceilings...) having conduits for fluids
Flooring
Control, e.g. regulation, of pumps, pumping installations or systems
Multiple-way valves, e.g. mixing valves, pipe fittings incorporating such valves
Supports for pipes, cables or protective tubing, e.g. hangers, holders, clamps, cleats, clips, brackets
Supports for pipes, cables or protective tubing, e.g. hangers, holders, clamps, cleats, clips, brackets
Branching pipes, joining pipes to walls
Domestic hot-water supply systems
Venting, aeration arrangements for water heating systems
Arrangements or mounting of control or safety devices for water heating systems
Air-conditioning systems, e.g. air-conditioning units using radiation from walls or panels, cool ceilings
Water haters for central heating incorporating heater for domestic water
Connecting water heaters (not the radiator) to circulation pipes
Arrangements of inlet valves used with water heaters
Heat storage plants or apparatus in general
Tubular heat-exchangers
Hot-air central heating systems (F24D 10/00, F24D 11/00 take precedence; air conditioning F24F); Exhaust gas central heating systems
Definition statement
This subclass/group covers:

Hot-air central heating systems:

  • the heat source being solar energy
  • operating with discharge of hot air into the space or area to be heated
  • operating without discharge of hot air into the space or area to be heated
  • using heat pumps.
Relationship between large subject matter areas

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.

References relevant to classification in this group
This subclass/group does not cover:
Air conditioning systems able for cooling and heating
District heating systems
Central heating systems using heat accumulated in storage masses
Informative references
Attention is drawn to the following places, which may be of interest for search:
Air heaters having heat generating means
Combined water and air heaters
Arrangements or mounting of control or safety devices for air heating systems
Central heating systems using heat pumps
Central heating systems employing heat-transfer fluids not covered by groups F24D 1/00 to F24D 5/00, e.g. oil, salt, gas (F24D 10/00, F24D 11/00 take precedence)
Definition statement
This subclass/group covers:

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

Relationship between large subject matter areas

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

References relevant to classification in this group
This subclass/group does not cover:
District heating systems
Central heating systems using heat accumulated in storage masses
Central heating systems employing combinations of heat transfer fluids covered by two or more of groups F24D 1/00 to F24D 7/00 (F24D 10/00, F24D 11/00 take precedence)
Definition statement
This subclass/group covers:

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

References relevant to classification in this group
This subclass/group does not cover:
District heating systems
Central heating systems using heat accumulated in storage masses
District heating systems
Definition statement
This subclass/group covers:

District heating systems with:

  • domestic delivery stations having a heat exchanger
  • direct domestic delivery stations

"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.

Relationship between large subject matter areas

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

Informative references
Attention is drawn to the following places, which may be of interest for search:
Heat exchanger
F28
Air conditioning
Steam engine plants, steam accumulators, engine plants not otherwise provided for, engines using special working fluids or cycles
Arrangements of mounting of control or safety devices for steam heating systems
District heating systems with heat accumulated in storage masses
District heating systems with heat accumulated in storage masses and using a heat pump
Systems for controlling or regulating non-electric variables
Central heating systems using heat accumulated in storage masses (self-contained storage heating units F24D 15/02; storage masses, see the relevant subclasses)
Definition statement
This subclass/group covers:

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

  • district heating systems
  • water heating systems
  • air heating systems
  • using heat pumps
Relationship between large subject matter areas

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 which storage mass staying in the tank 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

Systems comprising a further storage tank for domestic hot water are classified in F24D 3/08.

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

Arrangements for domestic- or space-heating systems consisting of self-contained heating units (i.e. not connected to a central unit) using heat pumps are covered in F24D 15/02.

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

Domestic hot-water with accumulation of heated water are covered in F24D 17/00.

Details of the control central heating systems are covered by the relevant subgroup in F24D 19/1006.

References relevant to classification in this group
This subclass/group does not cover:
Self-contained storage heating units
Domestic hot-water supply system with accumulation of heated water
Informative references
Attention is drawn to the following places, which may be of interest for search:
Central heating system with domestic hot water storage tank
Other central heating systems not covered by groups F24D 1/00 to F24D 11/00, in particular systems wiht more than one heat source
Heat storage plants or apparatus in general
Air-conditioning systems or apparatus not covered by F24F 1/00 or F24F 3/00
Details of water storage tanks with water being able to flow outside the tank for being used
Storage heaters with storage masses staying in the tank and with the transfer fluid being a liquid
Use of solar heat, e.g. solar heat collectors
Arrangement or mounting of control or safety devices for water heating systems
Combined heating and refrigeration systems, e.g. operating alternately or simultaneously
Heat pumps as such
Central heating system with domestic hot water storage tank
Heat storage plants or apparatus in general
Air-conditioning systems or apparatus not covered by F24F 1/00 or F24F 3/00
Storage heaters for fluids using heat pumps
Use of solar heat, e.g. solar heat collectors
Other production or use of heat, not derived from combustion
Other central heating systems
Definition statement
This subclass/group covers:

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.

Relationship between large subject matter areas

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.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Cogeneration machines
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
Electric heating systems (electric water or air heaters F24H)
Definition statement
This subclass/group covers:
  • Electric heating systems solely using resistance heating, e.g. under-floor heating
  • Electric heating systems using electric heating of heat-transfer fluid in separate units of the system, e.g. radiators connected to the central heating systems by fluid pipes comprising additional electric heating means.
Relationship between large subject matter areas

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

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

Details of electric heating means as such are covered by H05B 3/00.

Details of the control for electric heating systems are covered by the relevant subgroup in F24D 19/1096.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Layered products essentially comprising sheet glass, or glass, slag, or like fibres
Flooring
Arrangements or mounting of control of safety devices for electric heating systems
Ohmic-resistance heating
Other domestic- or space-heating systems
Definition statement
This subclass/group covers:

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

  • self-contained heating units, e.g. storage heaters
  • using heat pumps. This class covers arrangements in which the refrigerant of the heat pump flows directly through the radiator or the heating panel and transfers heat to the space to be heated without an intermediate hot water central heating circuit being located between the heat pump loop and the space to be heated.
Informative references
Attention is drawn to the following places, which may be of interest for search:
Fluid heaters using heat pumps, the fluid being a liquid, comprising storage means
Domestic hot-water supply systems (combined with domestic- or space-heating systems F24D 1/00 to F24D 15/00)
Definition statement
This subclass/group covers:

Domestic hot-water supply systems using

  • solar energy
  • heat pumps
  • conventional heating means
  • combination of different kinds of heating means.

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

Domestic hot-water supply systems comprising recirculation systems.

Relationship between large subject matter areas

Details of the control for domestic hot-water systems are covered by the relevant subgroup in F24D 19/1051.

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

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

Informative references
Attention is drawn to the following places, which may be of interest for search:
Treatment of water, waste water, or sewage
Methods or layout of installations for water supply
Water main or service pipe systems
Domestic plumbing installations for fresh water or waste water, Sinks
Combined heating and refrigeration systems, e.g. operating alternately or simultaneously
Heat pumps
Arrangement or mounting of control or safety devices for water heating systems and for domestic hot water
Air-conditioning systems or apparatus not covered by F24F 1/00 or F24F 3/00 [N: e.g. using solar heat, combined with household units such as an oven or water heater]
Fluid heaters using heat pumps
Use of solar heat, e.g. solar heat collectors
Heat storage plants or apparatus in general
Heat-exchange apparatus not covered by any of the groups F28D 1/00 to F28D 20/00
Details (of water or air heaters F24H 9/00; of heat-exchange or heat-transfer apparatus, of general application F28F)
Definition statement
This subclass/group covers:

Details of heating systems, in particular:

  • Arrangements for connecting central heating radiators to circulation pipes
  • Details related to central heating radiators: e.g. humidifiers for radiators, fan arrangements, magnets for attaching a cover, etc.
  • devices for preventing or removing corrosion, slime or scale
  • devices for preventing damage by freezing
  • arrangement of mountings or supports for radiators
  • casings, cover lids or ornamental panels, for radiators
  • arrangements for drainage, venting or aerating
  • arrangement or mounting of control or safety devices.
Relationship between large subject matter areas

This group covers details concerning the heating system and the central heating radiators.

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 central heating radiators to circulation pipes are covered by F28D19/00A.

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.

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

Filters in general are covered by B01D 29/00.

Anodic or cathodic protection in general is covered by C23F 13/00.

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

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 able to be used elsewhere are classified in the relevant subclass in F16K.

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

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

References relevant to classification in this group
This subclass/group does not cover:
Casings, cover lids or ornamental panel for heaters (not central heating radiators)
Arrangements of mountings or supports of heaters (not central heating radiators)
Grips, hooks or the like for hanging-up towels (on a central heating radiator)
Supporting means for linen or garments to be dried or aired on attachments or suspension to central heating radiators
Central heating radiators as such
Informative references
Attention is drawn to the following places, which may be of interest for search:
Degasification of liquids
Filters
Anodic or cathodic protection
Priming, Preventing vapour lock
Devices, e.g. valves, for venting or aerating enclosures
Construction of housing, use of materials therefore
Devices or appurtenances for use in, or in connection with, pipes or pipe systems
Regulating fuel supply
Control or safety systems or apparatus
Control of a water heater
Measuring quantity of heat conveyed by flowing mediums, e.g. in heating systems
Control of temperature
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Last Modified: 10/11/2013