Grundfos SCALA: A guide to models for maintaining the right pressure at home.

Grundfos SCALA: A guide to models for maintaining the right pressure at home.

When the water in your home is trickling – a shower that loses power, sprinklers that don't open properly, taps that alternate between hot and cold – there's often just one problem: insufficient pressure .
The most modern solution is a compact, self-priming pressure booster , such as the Grundfos SCALA series, designed specifically for domestic use and small commercial applications.

In this article we see:

• What is Grundfos SCALA and how does it work?

• the differences between SCALA1 and SCALA2

• the main models (3-35, 3-45, 5-55) and for which systems they are suitable

• How to choose the right model for your home

What is Grundfos SCALA?

The Grundfos SCALA range consists of “all-in-one” multistage booster sets : in a single compact body you have a pump, motor, diaphragm tank, sensors, check valve and electronic control unit.

In practice:

• connects directly to pipes (1" inlet and outlet)

• It is suitable for both mains water supply and shallow tank, cistern or well (up to approximately 8 m)

• It is self-priming , so it can suck from below after the first commissioning

• It has integrated protections against dry running, overtemperature and pump blocking

The goal is to ensure constant pressure throughout the home , even when multiple points of use are opened at the same time.

Grundfos SCALA1 vs. SCALA2: The main differences

The range is divided into two families:

• Grundfos SCALA1 – smart booster with Bluetooth and twin control

• Grundfos SCALA2 – booster with integrated inverter to maintain constant pressure as consumption varies

SCALA1: flexibility and connectivity

Grundfos SCALA1 is a complete pressurization unit designed for domestic and light commercial use (e.g. greenhouses, small irrigation, car washes, fruit/vegetable counters in supermarkets).

Key Features:

• Built-in Bluetooth : Management via Grundfos GO REMOTE app (configuration, diagnostics, alarms)

• possibility of twin configuration (two pumps in parallel) to increase flow rate and operating safety

• suitable for:

  • increased pressure from the aqueduct

  • Feed from roof tank, burst tank or cistern

  • sampling from a surface well (depth < 8 m)

• quiet operation and high performance

SCALA2: maximum comfort and perfectly constant pressure

Grundfos SCALA2 is a self-priming pump with an integrated inverter : a sensor continuously monitors the outlet pressure and adjusts the motor speed to keep it constant, even if several taps are opened.

Strengths:

• constant pressure at the tap thanks to speed control

• very low noise level (typically < 47 dB(A) in use)

• 3-step “plug & play” installation (connect pipes, prime, power supply)

• ideal for homes up to 3 floors and 8 collection points

If your goal is maximum comfort (a constantly stable shower, no sudden drops), SCALA2 is the reference.

The main Grundfos SCALA models and their applications

Below is an overview of the most popular models in the SCALA1 and SCALA2 range for domestic use:

Grundfos SCALA1 models

In the SCALA1 family you will mainly find:

• SCALE1 3-35 – fixed speed home booster, suitable for:

  • small/medium-sized single-family homes

  • domestic use with standard consumption (2–4 simultaneous points of use)

• SCALE1 3-45 – more “pushed” mainly, suitable for:

  • 2–3 story homes

  • systems with more extensive pipes or combined use of home + garden

• SCALA1 5-55 – model with even higher heads, ideal for:

  • larger homes

  • irrigation of large gardens or small commercial applications

Many of these models also exist in a Twin version (two pumps in parallel) for those who need:

• greater range

• redundancy (if one pump stops, the other continues to work)

Grundfos SCALA2 3-45 model

For the SCALA2 family, the reference model is:

• Grundfos SCALA2 3-45

Main indicative technical characteristics:

• nominal flow rate approximately 3 m³/h

• maximum head up to 45 m

• suitable for:

  • increased pressure from the network

  • power supply from tanks (roof, underground, cisterns)

  • surface wells (up to 8 m)

Thanks to speed control, the pump automatically modulates its power based on consumption, optimising both comfort and energy consumption .

How to choose the right Grundfos SCALA model

To choose correctly between SCALA1 and SCALA2 (and between the different models) I recommend you evaluate these aspects:

1. Type of water supply

• Aqueduct with low or variable pressure
  → SCALA2 is ideal for “stabilizing” the pressure thanks to the inverter.

• Tank, cistern, rainwater collection
  → Both SCALA1 and SCALA2 are fine; choose based on your comfort requirements and budget.

2. House size and number of floors

• Apartment or small house (1–2 floors, few uses):
  → SCALE1 3-35 or SCALE2 3-45

• House on 2–3 floors with multiple bathrooms and garden:
  → SCALE1 3-45 or SCALE2 3-45

• Large home or small business with many water uses:
  → SCALA1 5-55 (also in Twin version if high capacities are required)

3. Comfort and silence

If the pump is installed near inhabited areas (e.g. laundry room adjacent to bedrooms, internal technical room):

• SCALA2 is often preferred for its very low noise level and constant pressure at the tap.

4. Management and control

• If you are interested in monitoring and configuring your pump from your smartphone , creating reports or managing hard-to-reach systems,
  → SCALA1 with Bluetooth and Grundfos GO REMOTE app is a very convenient choice.

Advantages of the Grundfos SCALA range

In summary, why choose a Grundfos SCALA pump over a traditional booster pump?

• Everything integrated into a single body (fewer components, less risk of installation errors)

• Integrated electronic protections (dry running, overtemperature, overload)

• Low noise , also suitable for domestic environments

• Self-priming : ideal for tanks or surface wells

• Inverter models (SCALA2) for comfort and energy savings

• Models with Bluetooth (SCALA1) for smart management from the app

Conclusion

The Grundfos SCALA series (SCALA1 and SCALA2) today represents one of the most complete solutions for those who want to definitively solve low pressure problems at home , without complex systems and with an eye on comfort and consumption.

• If you are looking for maximum comfort, constant pressure and silence , go for SCALA2 3-45 .

• If you need flexibility, the possibility of twin configurations and app management , opt for SCALA1 and choose between 3-35, 3-45 or 5-55 based on the size of the system.