Hot water system. Types, scheme and device

Hot water system. Types, scheme and device

An open hot water system is a system in which water for hot water supply is taken directly from the supply and return pipelines of the heating network (heating system), mixed in special devices – hydraulic elevators and supplied to the water taps.

A closed DHW system is a hot water system in which cold water is taken from the water supply network, heated by the heat of the network water in special heaters – boilers located in heating points (in the basements) of houses, without touching or mixing with the coolant – water of the heating system, and then enters to water taps of the DHW system MKD.

There are independent open DHW systems , in which there are no connections between hot water and heating pipelines, and cold water for DHW needs, taken from the water supply network, is heated at the , in district or house (roof) boiler houses and supplied to the MKD through separate hot water supply networks …

hot water systems

The pressure (and, accordingly, the flow rate) of hot water systems


in the hot water supply systems is created by pumps located at the CHPP, in the district or house (roof) boiler houses.

Most DHW systems, in accordance with regulatory documents, have a circulation system – pipelines and / or circulation pumps through which water is continuously circulated. As a result, along the entire length of the hot water supply pipelines, including near the water taps, the water temperature is constantly maintained in accordance with the requirements of the standards – not lower than 60 degrees C.

A hotline may not have a circulation line only if it is not designed by illiterate “specialists” or if it is “forgotten” to build by thieving builders with the connivance of accomplices – the city authorities, or if they steal housing and communal services plumbers for scrap.

However, in cases where hot water is constantly drawn from the hot water system (in baths, in technological installations) and with a short length of supply pipelines from the heat source to the points of water intake, the hot water system may not have circulation.

Both open and closed hot water system during design, installation and reconstruction should be equipped with devices for automatically maintaining the water temperature within the standard values

Rob Prosser

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