The hydronic gas gas furnaces have weird pipe arrangements, which can be open or closed; the piping system distribution may be a single pipe, various pipes, or numerous pipes.
These pipes carry water, back plus forth, throughout the system plus supply steam to the radiators to produce heat.
There is no water loss in this system. The first type is the open piping system. This system has an expansion tank that opens to the atmosphere plus a water loop system – hydronic heating that actually involves heating with the help of water instead of steam… It has a single pipe that runs throughout the system as well… When a room needs heat, the radiator heats the water, which, in turn, heats the area. The direct return piping allows the piping to run in a direct path, thus optimizing piping costs as well! Larger hydronic systems use a reverse return piping design with a closed-loop system plus a return header attached to a remote hydraulic load. This design ensures the water flow plus pressure distributed equally across the system, and a closed piping system is sealed completely to avoid interference from atmospheric pressure. The other type is the single-pipe arrangement which uses a single pipe to serve as both the supply plus the return line. This system is correct in small homes for sure. The fifth type is the four-pipe system. It’s simply a multiple-pipe heating plus a multiple-pipe cooling system. It uses primary plus additional units in big industrial buildings, big residential areas, plus larger commercial buildings where zoning is required. In this system, the primary pump circulates water continuously throughout the building through the primary circuit, but consult an HVAC worker or an HVAC business when purchasing, installing, or inspecting a hydronic system.