Grundfos ALPHA1 GO 25-40 180 Circulating Pump

The Grundfos ALPHA1 GO 25-40 180 circulator pump, reference 93074185, is a high-efficiency electronic circulator designed to move water in heating and HVAC systems. It offers a maximum head of 4 meters, nominal flow rate of 1.65 m³/h, modulating electrical power from 4 to 27 W, G 1½" threaded connections, and an installation length of 180 mm.

The ALPHA1 GO range is especially suited both for new installations and for the replacement of existing circulator pumps. It features electronic control via proportional pressure, constant pressure, or constant curve, dry-run protection, self-venting function, and robust startup. In addition, the Grundfos GO tool helps the installer identify the appropriate setting when replacing older pumps.

Circulator pump with a maximum head of 4 meters

The Grundfos ALPHA1 GO 25-40 180 provides a maximum head of 4 m, a feature represented by the 25-40 model designation.

For reference 93074185, Grundfos specifies a nominal flow rate of 1.65 m³/h and a nominal head of approximately 1.89 m. The actual operating point will depend on the pressure losses in the circuit and the selected control mode.

The integrated electronics allow the pump operation to be adapted to the hydraulic needs of the installation, avoiding permanent operation at a fixed speed when it is not necessary.

Three control modes

The ALPHA1 GO allows different control strategies to be selected to suit various heating system types.

• Proportional pressure: adapts the differential pressure to changes in flow rate. Grundfos especially recommends it for radiator systems with thermostatic valves.
• Constant pressure: maintains a stable differential pressure regardless of flow variations. It is especially suitable for underfloor heating installations and manifold systems.
• Constant curve: maintains operation along a fixed curve, useful when behavior equivalent to constant speed is required.

Each of these modes has three adjustment levels I, II and III selectable directly from the pump front panel.

Advanced mode for circulator replacement

One of the main advantages of the ALPHA1 GO range is its focus on the replacement of old circulator pumps, both standalone and certain integrated models.

The advanced mode allows the pump to be configured to reproduce operating curves equivalent to those of certain replaced circulators.

Using the Grundfos GO replacement tool, the installer can enter or scan the data of the old pump. The app identifies a compatible alternative and provides the configuration that must then be selected on the ALPHA1 GO panel.

Use with Grundfos GO for replacements

The Grundfos GO app makes it easier to find the right circulator when carrying out a replacement. The installer can search for the existing model or enter its reference to obtain information about the recommended alternative and the required settings.

On the ALPHA1 GO, the app acts as a replacement assistance tool: it provides the parameters that must be entered manually from the pump panel.

It is important to distinguish this feature from the ALPHA2 GO: the ALPHA1 GO does not connect directly via Bluetooth to the app. Direct connectivity and advanced digital functions belong to the ALPHA2 GO.

Suitable for radiators and underfloor heating

Thanks to its different control modes, the ALPHA1 GO can adapt to different closed-loop HVAC circuits.

Typical applications include:

• Radiator heating systems.
• Underfloor heating installations.
• Closed heating circuits.
• Compatible HVAC systems.
• Replacement of standalone circulators.
• Replacement of certain compatible integrated UPS circulators.

Dry-run protection

The Grundfos ALPHA1 GO includes dry-run protection, designed to protect the pump when there is not enough liquid for proper operation.

This function increases protection of the hydraulic system against abnormal situations during commissioning or operation of the installation.

Self-venting function

The range includes a self-venting function that helps remove air present inside the pump during operation.

Air can cause noise and reduce hydraulic performance, so this feature makes commissioning easier and contributes to more stable operation.

The pump function does not replace proper venting of the rest of the hydraulic installation.

Robust startup against blockages

The ALPHA1 GO features Robust Startup. When the rotor encounters resistance, the electronics attempt to start it using high starting torque.

This feature helps reduce the risk of blockage caused by dirt deposits, magnetite, or limescale, especially after long periods when the installation has been out of service.

High-efficiency electronic motor

The pump uses an electronically commutated motor and includes an integrated frequency converter, allowing electrical consumption to be adjusted according to circuit demand.

For reference 93074185, the absorbed electrical power is between:

• Minimum power: 4 W.
• Maximum power: 27 W.

The EEI energy efficiency index is 0.20, placing the pump in the category of high-efficiency electronic circulators.

Quiet operation

Grundfos has designed the ALPHA GO range to provide low-noise operation, suitable for domestic installations where the pump may be located near living spaces.

Electronic control also helps avoid speeds and pressures higher than necessary, which can produce hydraulic noise in valves and circuits.

G 1½" connection and 180 mm installation length

The Grundfos ALPHA1 GO 25-40 180 features G 1½" threaded connections in accordance with ISO 228-1.

The distance between connections is 180 mm, a very common size in circulator pumps for heating installations.

These features are especially important when the pump is used to replace an existing unit, as both the installation length and connection size must be checked.

Maximum operating pressure of 10 bar

The pump supports a maximum operating pressure of 10 bar and its connections are rated PN 10.

The hydraulic circuit must be designed so that operating pressure remains within the values permitted by the pump and the rest of the installation components.

Liquid temperature from 2 to 110 °C

For the specific reference 93074185, Grundfos Product Center documentation specifies a liquid temperature range of 2 to 110 °C.

This wide range allows the circulator to be used in different closed heating and HVAC systems, provided that the fluid characteristics and the rest of the components are compatible.

The permitted ambient temperature during operation is between 0 and 55 °C.

Cast iron hydraulic body

The pump body is made of EN-GJL-150 cast iron, a material commonly used in circulators intended for closed heating circuits.

The impeller is made of PES composite material reinforced with 30% glass fiber.

This standard cast iron version is intended for closed heating and HVAC systems and should not be confused with specific stainless steel versions intended for other applications.

Single-phase 220-240 V power supply

The ALPHA1 GO 25-40 180 operates on a single-phase 220-240 V, 50/60 Hz power supply.

Its current consumption is approximately between:

• Minimum current: 0.06 A.
• Maximum current: 0.30 A.

Motor protection is electronic and Grundfos specifies insulation class F.

IP44 protection

The pump has an IP44 protection rating, providing protection against the ingress of solid objects and water splashes under the conditions defined by the classification.

Installation must always respect the mounting positions, environmental conditions, and electrical requirements specified by Grundfos.

Technical features of the Grundfos 93074185

• Brand: Grundfos.
• Range: ALPHA1 GO.
• Model: ALPHA1 GO 25-40 180.
• Reference: 93074185.
• Type: electronic circulator pump.
• Application: heating and HVAC.
• Nominal flow rate: 1.65 m³/h.
• Nominal head: 1.89 m.
• Maximum head: 4 m.
• Installation length: 180 mm.
• Connection type: threaded G.
• Connection size: G 1½".
• Connection standard: ISO 228-1.
• Nominal pressure: PN 10.
• Maximum operating pressure: 10 bar.
• Liquid temperature: 2 to 110 °C.
• Ambient temperature: 0 to 55 °C.
• Power supply: 1 x 220-240 V.
• Frequency: 50/60 Hz.
• Minimum absorbed power: 4 W.
• Maximum absorbed power: 27 W.
• Minimum current: 0.06 A.
• Maximum current: 0.30 A.
• EEI energy efficiency index: 0.20.
• Frequency converter: integrated.
• Thermal protection: electronic.
• Protection rating: IP44.
• Insulation class: F.
• Body material: EN-GJL-150 cast iron.
• Impeller material: PES + 30% glass fiber.
• Proportional pressure: yes.
• Constant pressure: yes.
• Constant curve: yes.
• Control levels: I, II and III.
• Advanced replacement mode: yes.
• Dry-run protection: yes.
• Self-venting function: yes.
• Robust startup: yes.
• Replacement assistance via Grundfos GO: yes.
• Direct Bluetooth connection with Grundfos GO: no.
• Net weight: 1.92 kg.
• Gross weight: 2.11 kg.
• EAN: 5715467404128.

ALPHA1 GO for replacement and new installations

The Grundfos ALPHA1 GO 25-40 180 combines electronic control, low power consumption, and a standard 180 mm format to facilitate both new installations and the replacement of existing circulators.

Its three control modes, 4-meter maximum head, G 1½" connection, dry-run protection, self-venting, and robust startup provide the main functions needed for domestic heating and HVAC circuits.

In addition, Grundfos GO assistance for identifying replacement pumps and reproducing settings simplifies the installer’s work when modernizing existing systems, while keeping this ALPHA1 GO easy to configure directly from its control panel.