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Two-pipe system
There are two basic categories of pipe systems: one-pipe and two-pipe sytems. The type of system installed will have an influence on dimensioning radiators and piping. A general characteristic of a two-pipe system is that the radiators are dimensioned for the same flow temperature and the same temperature difference.
U-value
The U-value describes the heat loss per sq. metre in relation to the temperature difference between the interior and exterior.
Uniform corrosion
Metallic corrosion involves the loss of metal at a spot on an exposed surface – ranging from uniform attacks over the entire surface to severe local attacks.
UV water treatment
UV treatment of water is a common method of combating microorganisms. This procedure treats only bacteria that passes the UV bulb and should be regarded as a gatekeeper. This procedure gives no long term protection.
Variable frequency drive
A variable frequency drive is used for adjusting a flow or pressure to the actual demand. It controls the frequency of the electrical power supplied to a pump or a fan. Significant power savings can be achieved when using a VFD.
Vortex impeller
The benefit of a vortex impeller over a channel impeller is the minimised risk of clogging.
Wastewater
Wastewater is a common designation for any water that in one or another way has been affected in quality by human influence.
Wastewater pumping station
Pumping stations in sewage collection systems are normally designed to handle raw sewage that is fed from underground gravity pipelines.
Water filtration
Filtration of water is a method of combating microorganisms. This procedure treats only bacteria which passes the filter. This method should be regarded as a gatekeeper.
Water flow rate
Required heating capacity and required temperature differential of the medium are relevant when calculating the design water flow rate for a heating system.