A condensing boiler is provided with a condenser, by which the water vapour produced by the burning of gas or oil in the boiler, condenses back into liquid water - hence the name condensing boiler. The energy contained in the vapour, would without a condenser, normally discharged to the atmosphere through the flue.
Conductivity transmitters measure the electrical conductivity in a liquid. This is done in order to avoid excessive salinity, which can cause corrosion in e.g. air-conditioning systems.
Constant differential pressure, control mode
Constant differential pressure can be used in circulating systems with a pipe system with low pressure loss and with control valves to generate a variable flow.