Grundfos ALPHA2 25-80 180

The ALPHA2 25-80 180 is the high-head member of Grundfos’ ALPHA2 series, delivering an impressive 8 meters (80 kPa) of head pressure in a compact 25mm connection size. With a 180mm flange-to-flange distance, this pump is designed as a direct replacement for older high-head circulators in residential and light commercial systems. Unlike larger 32mm pumps, the 25mm connections make this unit compatible with standard residential piping while still delivering commercial-grade pressure performance.

Key Benefits

• High Head (8m / 80 kPa): Ideal for multi-story buildings (3+ floors), long pipe runs, or systems with high resistance (many radiator valves, small diameter pipes).

• Standard 25mm Connections: Direct fit for residential piping systems without requiring adapters or pipe modifications.

• Up to 85% Energy Savings: Consumes as little as 6 Watts – massive savings compared to older UPS 25-80 fixed-speed pumps.

• AUTOADAPT Technology: Pump learns your system’s characteristics and continuously optimizes performance.

• 180mm Flange Distance: Standard replacement size for older 180mm circulators from multiple brands.

• Alarm Relay Output: Remote fault signalling for integration with building management systems.

Performance Details
The ALPHA2 25-80 180 delivers a maximum head of 8 meters (80 kPa) and a maximum flow rate of 4.5 m³/h. Operating modes include:

• AUTOADAPT: Automatically selects between proportional and constant pressure modes based on system demand.

• Constant Pressure (3 settings – low/medium/high): Best for underfloor heating or systems with pressure-dependent valves.

• Proportional Pressure (3 settings – low/medium/high): Optimal for radiator systems (pressure decreases as flow drops).

• Constant Curve (3 speeds): For system flushing, troubleshooting, or simple on/off operation.

The pump includes night setback mode for domestic hot water recirculation and a manual speed override for technician troubleshooting.

Applications & Usage

• Large residential heating (3+ stories, 3500-6000 sq ft)

• High-resistance radiator systems (many TRVs, small bore pipes)

• Multi-family buildings (2-4 apartments)

• Light commercial hydronic heating (offices, retail, restaurants)

• Domestic hot water recirculation (long, high-resistance loops)

• Chilled water circulation (small commercial)

• Solar thermal systems (taller buildings)

• Heat pump distribution (high-head applications)

Why Choose 25-80 vs 32-80?

Choose the 25-80 for direct replacement in standard residential systems. Choose the 32-80 for larger pipework or higher flow requirements.

Durability & Reliability
Engineered for demanding continuous operation:

• Stainless steel rotor can (AISI 304) – corrosion-resistant

• Ceramic bearings & graphite thrust bearing – self-lubricating, wear-resistant

• Dry-running protection – automatic shutdown if water supply is lost

• Automatic de-airing function – prevents airlock damage during startup

• Cast iron housing (EN-GJL-200) – durable for decades

• IPX4D splash-proof rating – safe for mechanical rooms

• Alarm relay output – remote fault signaling for BMS integration

Customer Value
For NPF Store customers facing pressure problems – cold radiators on upper floors, slow hot water circulation, or noisy systems – the ALPHA2 25-80 180 delivers the power needed to push water through high-resistance systems. It replaces older inefficient pumps directly (180mm flange, 25mm connections) while cutting energy costs by up to 85%. The pump pays for itself in energy savings within 12-18 months, and the AUTOADAPT feature ensures you never waste energy on over-pumping.

4. Key Features

• ✅ 8m Head (80 kPa) – Maximum pressure for multi-storey and high-resistance systems

• ✅ Standard 25mm Connections – Direct fit for residential piping systems

• ✅ 180mm Flange Distance – Drop-in replacement for older high-head circulators

• ✅ AUTOADAPT Technology – Self-optimizing performance for peak efficiency

• ✅ Energy Class A (EEI ≤ 0.20) – Ultra-low power consumption (6–55W)

• ✅ Night Setback Mode – Automatic reduction for DHW recirculation

• ✅ Alarm Relay Output – Remote fault signaling for monitoring systems

• ✅ Automatic Air Purge – Self-venting during installation and operation

• ✅ LED Status Display – Color-coded for easy troubleshooting

• ✅ Dry-Running Protection – Prevents damage from water loss

• ✅ Ceramic & Graphite Bearings – Long service life (50,000+ hours)

• ✅ 3 Operating Modes – AUTOADAPT, Constant Pressure, Proportional Pressure, Constant Curve

5. Technical Specifications