GRUNDFOS DATA BOOKLET GRUNDFOS ALPHA2 Circulator pumps 50/60 Hz

General data Circulator pumps Type key Performance range Applications Pumped liquids Control of heating systems Advantages of pump control Automatic Night SetBack Construction Sectional drawing Material specification Motor and control box Pump housing with air separator Installation Electrical data Start-up Liquid temperature System pressure Inlet pressure Setting of pump head Guide to performance curves Curve conditions Technical data Union and valve kits Insulation kits Service kit Product numbers Further product documentation WebCAPS WinCAPS

1. General data GRUNDFOS ALPHA2 offers a host of advantages: Circulator pumps GRUNDFOS ALPHA2 is a complete range of circulator pumps featuring: • AUTOADAPT function which suits most installations. • Integrated differential-pressure control enabling adjustment of pump performance to the actual system requirements. • Automatic Night SetBack (selectable). • Display showing the actual power consumption in Watt. • Motor based on permanent-magnet/compact-rotor technology. The GRUNDFOS ALPHA2 pump is energy-optimised and complies with the EuP Directive (EC Commission Regulation No 641/2009) which will...

1 GRUNDFOS ALPHA2 is designed for circulating liquids in heating systems. Pumps with stainless-steel pump housing can also be used in domestic hot-water systems. GRUNDFOS ALPHA2 is suitable for • systems with constant or variable flows where it is desirable to optimise the pump duty point. • systems with variable flow-pipe temperature. • systems where night setback is desired. GRUNDFOS ALPHA2 is especially suitable for • installation in existing systems where the differential pressure of the pump is too high during periods of reduced flow demand. • installation in new systems for fully automatic...

1 Advantages of pump control The heating required in a building varies greatly during the day due to changing outdoor temperatures, solar radiation and heat emanating from human beings, electric appliances, etc. Add to this that the need for heating may vary from one section of the building to another and that the thermostatic valves of some radiators may be turned down by the users. These circumstances will cause an uncontrolled pump to produce a too high differential pressure when the heating demand is low. Possible consequences: • too high energy consumption • irregular control of the system...

Material specification GRUNDFOS ALPHA2 features selectable Automatic Night SetBack. Automatic Night SetBack is activated with the button on the control box. Factory setting of Automatic Night SetBack: Not active. Note If the pump has been set to speed I, II or III, the night setback function is deactivated. Controller complete Stainless steel Radial bearing Construction GRUNDFOS ALPHA2 is of the canned-rotor type, i.e. pump and motor form an integral unit without shaft seal and with only two gaskets for sealing. The bearings are lubricated by the pumped liquid. The pump is characterised by •...

Standard position General data Faults preventing the pump from operating properly (e.g. blocking) are indicated in the display by "- -". Possible control box positions: Fig. 13 Pump housing with air-separating chamber [%] 100 Fig. 12 Cable entry with cable relief The cable entry incorporates cable relief. The pump housing with air separator is installed in systems where the liquid contains so much air that a circulator pump without air separator cannot start or keep up a continuous circulation. The pump housing is available only for upward water flows. The air-containing liquid is guided from...

Cast-iron pumps: +2 °C to +110 °C. Stainless-steel pumps in domestic hot-water systems: +15 °C to +65 °C. In domestic hot-water systems, it is recommended to keep the liquid temperature below 65 °C to eliminate the risk of lime precipitation. To avoid condensation in the control box and stator, the liquid temperature must always be higher than the ambient temperature. See table. Liquid temperature In most cases, the installation of the ALPHA2 is reduced to the mechanical installation and the connection to the electricity supply. The pump must always be installed with horizontal motor shaft. General...

Change of performance The pump performance (flow and head) can be changed by pressing the control box push-button as indicated in the table below and fig. 16. AUTO ADAPT Fig. 16 Pump setting in relation to performance Setting Pump curve AUTOADAPT (factory setting) Highest to lowest proportional-pressure curve The AUTOADAPT function enables ALPHA2 to control the pump performance automatically within a defined performance range, see fig. 16: • Adjusting the pump performance to the size of the system. • Adjusting the pump performance to the variations in load over time. In AUTOADAPT, the pump is...

Guide to performance curves Each pump setting has its own performance curve (Q/H curve). However, AUTOADAPT covers a performance range. A power curve (P1 curve) belongs to each Q/H curve. The power curve shows the pump power consumption (P1) in Watt at a given Q/H curve. The P1 value corresponds to the value that can be read from the pump display. See fig. 17. AUTO ADAPT Fig. 17 Performance curves in relation to pump setting Setting Pump curve AUTOADAPT (factory setting) Setpoint within the shaded area Lowest proportional-pressure curve Highest proportional-pressure curve Lowest constant-pressure...

The guidelines below apply to the performance curves on the next pages: • Test liquid: airless water. • The curves apply to a density of ρ = 983.2 kg/m3 and a liquid temperature of +60 °C. • All curves show average values and should not be used as guarantee curves. If a specific minimum performance is required, individual measurements must be made. • The curves for the speeds I, II and III are marked. • The curves apply to a kinematic viscosity of  = 0.474 mm2/s (0.474 cSt). • The conversion between head H [m] and pressure p [kPa] has been made for water with a density of  = 1000 kg/m3. For...