PLUMBING Presentation on Central Heating – Pump Position

At the end of this part you should be able to: Central Heating – System Components (Part 1) Explain the working principles of domestic circulating pumps used on central heating systems

Central Heating – System Components (Part 1) Domestic circulating pumps Ball type valve Gate type valve

Central Heating – System Components (Part 1) Pumps are fairly simple really. They consist of an electric motor which drives a circular fluted wheel called an impeller; this ‘accelerates’ the flow of water by centrifugal force. Most pumps have three settings, and pump manufactures provide performance data for each. This will show: Flow rate in litres per second Pressure in k Pa and m head Flow rate should not exceed 1 litre per second for small-bore systems and 1.5 litres for micro bore systems, above this and you could get noise in the system. Most manufacturers’ pumps deliver 5 or 6m head.( 5mtr head classed as standard and 6mtr head classed as ‘high head’) Pump impeller Water sucked in Water expelled out Direction of rotation

Pump located in this position would create negative pressure within the system, this would work but does create undesirable problems. Air could be drawn in through the open vent or aerated water in through the cold feed. Central Heating – System Components (Part 1)

Cold feed & vent separated resulted in the water pumping over the vent. Central Heating – System Components (Part 1)

Correctly fitted pump to give positive pressure around the system. 150mm Max Central Heating – System Components (Part 1)

End of Session