The pump moves heating water from the boiler to the radiators and underfloor heating. Without it the water moves slowly, distant rooms stay cold and the boiler overheats.<\/p>\n\n\n\n
Wall-hung gas boilers already have a built-in pump. A separate pump is needed if:<\/p>\n\n\n\n
Take a pump marked 25\/60 180<\/strong>:<\/p>\n\n\n\n Head shows how much resistance from the pipes and radiators the pump can overcome. The pump reaches its maximum head at zero flow, so you need to look at the duty point on the performance curve.<\/p>\n\n\n\n The flow rate is calculated from the system output:<\/p>\n\n\n\n Flow rate (m\u00b3\/h) = 0.86 \u00d7 output (kW) \/ difference between flow and return (\u00b0C).<\/strong><\/p>\n\n\n\n For a house with a 20 kW boiler and radiators with a 20 \u00b0C difference: 0.86 \u00d7 20 \/ 20 = 0.86 m\u00b3\/h. For underfloor heating the difference is smaller, usually 5-10 \u00b0C, so the flow rate in that circuit is higher.<\/p>\n\n\n\n For a private house of up to 200-250 m\u00b2, a pump with a 4-6 m head is usually enough. A more accurate head is calculated for the longest branch: pipe length, number of fittings, resistance of the radiators, valves and underfloor heating manifold.<\/p>\n\n\n\n An oversized pump is also a mistake. It causes noise in the pipes and valves and increases electricity consumption.<\/p>\n\n\n\n A classic pump<\/strong> (for example, the UPS series) has 2-3 fixed speeds. The speed is set manually during commissioning.<\/p>\n\n\n\n An energy-efficient pump<\/strong> (for example, ALPHA2) adjusts its speed to the system's demand automatically. When thermostatic heads close some of the radiators, the pump reduces its output. Power consumption is several times lower and it runs almost silently.<\/p>\n\n\n\nNumber<\/th> What it means<\/th><\/tr><\/thead> 25<\/td> Connection size, DN 25 (1\u00bd» thread)<\/td><\/tr> 60<\/td> Maximum head \u2014 6 m of water column<\/td><\/tr> 180<\/td> Installation length of the pump body, mm<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n How to calculate the flow rate<\/h2>\n\n\n\n
How to estimate the head<\/h2>\n\n\n\n
Standard or energy-efficient pump<\/h2>\n\n\n\n
Installation rules<\/h2>\n\n\n\n