Pressure sensing method:
A feed pipe from the top of the boiler is connected to a pressure switch
, when there is no pressure inside the boiler, the contacts on the pressure switch
allow electricity through to the element, once the set pressure is achieved, usually set to 1 bar, the diaphragm expands inside the pressure switch
and opens the contacts which cuts off the electrical supply to the element.For
: simple mechanical operation.Against
: due to the mechanical operation there is a wide swing in switching points.