How to Install Grundfos SCALA1 and SCALA2: Complete Guide for Installers
Preparation, hydraulic connection, priming, pressure adjustment and configuration with the Grundfos GO app. Everything you need for a correct, safe and efficient installation.
Grundfos SCALA2
Integrated pressure tank · IPX4 · Bluetooth · 1.7 L priming
Grundfos SCALA1
Models 3-35, 3-45, 5-55 · Twin configuration · GO Remote app
1Why correct installation is essential
A correct SCALA2 and SCALA1 installation is essential for many reasons. Grundfos defines the direct consequences of good or poor installation:
Benefits of correct installation
- Optimal performance and constant pressure throughout the home
- Protection of pump and water system against damage
- Maximum energy efficiency
- Prevention of leaks and related damage
- Compliance with local plumbing regulations
- Reduced need for maintenance and repairs
Risks of incorrect installation
- Water leaks and damage to electrical components
- Excessive noise and vibrations
- Pressure fluctuations and loss
- Unnecessarily high energy consumption
- Possible voiding of product warranty
- Non-compliance with local regulations
2Official SCALA1 and SCALA2 installation videos
Grundfos has published official videos for installing each model. We recommend watching them before starting the installation to get a complete overview of the process:
Grundfos SCALA1 Installation
Official Grundfos Video · 4:12 minGrundfos SCALA2 Installation
Official Grundfos Video · 3:48 min3Preliminary preparation: tools, materials and installation location
Before starting the Grundfos booster pump installation, proper preparation is essential. Grundfos specifies preparation steps to ensure everything is ready.
1. Review product documentation and specifications
Review the installation and operating instructions, as well as the technical catalog (available at grundfos.com). Familiarize yourself with your SCALA's technical specifications: flow rate, maximum pressure, electrical supply and dimensions. Verify that the pump meets your customer's application requirements.
2. Choose suitable installation location
- The SCALA2 can be installed both indoors and outdoors (IPX4 rating).
- Consider factors such as accessibility, stability and proximity to the water source.
- Ensure there is sufficient space for future maintenance.
- The pump must be installed near a drain or in a drip tray connected to a drain — it is normal for the mechanical seal to show slight leakage during first startup until the faces are fully lubricated.
- Install the unit in a well-ventilated room to prevent condensation.
- If installed outdoors, protect it from direct sunlight.
- During winter, the system must be fully drained if there is risk of freezing.
3. Check electrical supply
Verify that the electrical supply meets the requirements specified in the product manual. Check if assistance from an electrician is needed for electrical connections. Any modification of electrical connections must be performed by a qualified electrician.
4. Prepare tools and materials
Required tools
- Fixed wrenches and pliers
- Pipe cutter
- PTFE tape (if no flat gaskets)
- Voltage tester
- Pressure gauge
- Hand pump for pre-charge
Required materials
- Appropriate pipes, fittings and valves
- WRAS-approved flexible hoses
- Expansion anchors and mounting screws
- Anti-vibration mat/pad (recommended)
- Drip tray (if applicable)
- Particle filter (if water contains solids)
4SCALA2 installation step by step
Follow this complete process for Grundfos SCALA2 installation. Remember that Grundfos's best practices checklist is a general guide — always consult the documentation supplied with your pump.
Disconnect electrical supply
Before any action, ensure you disconnect the electrical supply to the area where the pump will be installed to prevent accidents or electrical hazards.
Mark, drill and mount the pump
Mark and drill holes at the chosen location and insert expansion anchors. Place the noise-reducing mat — although the SCALA2 is already very quiet, the mat reduces additional vibrations. Position the pump on the mat and secure it to the floor with the four screws, ensuring it is level and stable.
Connect pipes and flexible hoses
Remove the two connectors by unscrewing them by hand. Mount the two flexible hoses onto each connector and tighten them with a wrench. Reinstall the connectors onto the pump, again by hand only. Fit the two flexible hoses onto the pipes and tighten them with a wrench.
Install particle filter (if applicable)
If the water contains particles or solids, install an inlet particle filter at this point, before water enters the pump. This will protect internal components and extend pump lifespan.
Prime the pump
Remove the priming plug (you can use a screwdriver to loosen it, but usually hand-tightening is sufficient). Pour 1.7 liters (0.45 gallons) of water into the priming hole. Insert and tighten the priming plug again by hand.
Open valves and connect electrical supply
Open shut-off valves and close the bypass valve to allow flow through the pump. Connect the SCALA2 and turn on the switch.
Start up and check operation
Locate the farthest faucet from the pump and open it completely — this will remove air from the pump and system. Adjust pressure by pressing the screen arrows until the farthest faucet delivers the desired water pressure. Check for unusual noises, vibrations or leaks.
Adjust integrated pressure tank pre-charge
Adjust pressure to 70% of the set point value, never higher. For the default set point of 3 bar, pre-charge should be 2.1 bar. See the complete table in Section 6.
5SCALA1 installation step by step
The Grundfos SCALA1 installation (models 3-35, 3-45 and 5-55) follows a process similar to the SCALA2. Consult the quick guide included in the box and the information on the back of the packaging before starting.
Positioning: dry, protected and well-ventilated location
Install the pump in a dry place, protected from rain and well-ventilated. The base must be flat and horizontal to ensure proper operation.
Connect pipes and valves
Install shut-off valves on suction and discharge sides. The SCALA1 has flexible connections that facilitate installation. Seal pipe connections with PTFE tape (if no flat gaskets). Tighten all connections by hand only.
Prime the pump
Before startup, the pump must be primed (filled with water). Follow the procedure indicated in the product quick guide.
Electrical connection
Connect the pump to a suitable power outlet that meets the requirements specified in the manual. Any wiring modifications must be performed by a qualified electrician.
Smart configuration with Grundfos GO app
Download the Grundfos GO app from the App Store or Google Play. Turn on the pump and enable Bluetooth. Pair the app with the SCALA1 pump by pressing the connection button on the pump. The app will guide you through complete system configuration.
6Pressure tank pre-charge: the 70% rule
The SCALA2 incorporates an integrated pressure tank that eliminates the need for an external tank. But for it to work correctly, the tank pre-charge must be adjusted during installation and checked annually.
Default set point: 3.0 bar → Pre-charge: 2.1 bar (30 psi)
The 3 steps to adjust pre-charge
Stop the system and depressurize
Stop the SCALA2 by pressing the stop button. Close the supply pipe and open a faucet to release residual system pressure.
Adjust air pressure in the tank
Unscrew the air valve cap on the pressure tank. Pump air to 70% of the set point. Replace the cap and tighten it well.
Open valve and restart SCALA2
Open the supply shut-off valve and restart the SCALA2.
Recommended pre-charge pressure table by Grundfos
| Set point bar (psi) | Optimal tank pre-charge bar (psi) | Notes |
|---|---|---|
| 5.5 (80) | 3.9 (57) | Check available inlet pressure * |
| 5.0 (73) | 3.5 (51) | Check available inlet pressure * |
| 4.5 (65) | 3.2 (46) | Check available inlet pressure * |
| 4.0 (58) | 2.8 (41) | — |
| 3.5 (51) | 2.5 (36) | — |
| 3.0 (44) ⭐ Default | 2.1 (30) | Factory default set point |
| 2.5 (36) | 1.8 (26) | — |
| 2.0 (29) | 1.4 (20) | — |
| 1.5 (22) | 1.1 (16) | — |
* For set points above 4.5 bar, verify that the available inlet supply pressure at your installation is sufficient. Source: Official Grundfos.
7Configuration and monitoring with the Grundfos GO app
Grundfos GO App: your SCALA control center
The Grundfos GO app helps you get the most out of SCALA1 pumps, whether you have a single pump or a Twin configuration system. Available for free on the App Store and Google Play.
Quick startup
Step-by-step guided configuration in minutes
Real-time monitoring
Trend data, metrics and operational history
Advanced customization
Alarms, scheduling, maximum runtime and much more
Alerts and alarms
Proactive notifications about any detected issues
Installation reports
Generate and share professional reports with the customer
Time scheduling
Limit runtime for applications like irrigation
How to pair the app with SCALA1
Connection and startup with Grundfos GO app
- Download the Grundfos GO app from the App Store or Google Play.
- Turn on the SCALA1 pump and enable Bluetooth on your phone.
- Press the connection button on the pump to start pairing.
- Select how the pump is connected: municipal network, elevated tank, cistern tank, well or other source.
- Indicate if there is an external input (e.g., a high-level switch in an elevated tank) and configure its behavior.
- Configure maximum runtime if desired (default disabled; if enabled, the pump stops and emits an alarm when exceeded).
- Enable or disable automatic alarm reset and enable cyclic alarm to detect small system leaks.
- Enter a unique name for the pump (very useful in projects with multiple pumps).
- Review the configuration summary and, if desired, generate a report to share with the customer.
SCALA1 dashboard from the app
Once configured, the SCALA1 dashboard in the Grundfos GO app provides access to:
- Events: Active alerts with description and detailed information.
- Trend data: Graphs of runtime and number of starts.
- Metrics: Detailed pump performance monitoring.
- Scheduling: Configure time intervals to limit operation (useful for irrigation).
- Advanced settings: Modify all configuration parameters.
⚡ SCALA1 Twin configuration: two pumps, maximum performance
If you install a SCALA1 Twin configuration, the Grundfos GO app allows configuring additional options:
- Operating mode: Standby mode (secondary pump acts as backup) or duty assist mode (both pumps work together to provide higher flow).
- Alternation type: To ensure balanced usage of both pumps, they can alternate at regular intervals based on runtime, number of starts, or a combination of both.
- Alternation frequency configuration: Define exact hours between alternations or number of starts between alternations.
8SCALA1 vs SCALA2 comparison: which model is right for you?
Both pumps in Grundfos's SCALA family are designed to provide perfect water pressure, but each has its differentiating features:
| Feature | SCALA1 | SCALA2 |
|---|---|---|
| Available models | 3-35, 3-45, 5-55 | Single model with variants |
| Integrated pressure tank | No (external tank) | ✔ Yes (simplifies installation) |
| Twin configuration | ✔ Yes (dual pump) | No |
| Grundfos GO app | ✔ Yes (GO / GO Remote) | ✔ Yes (Bluetooth) |
| Installation report | ✔ Via app | ✔ Via app |
| Outdoor IP rating | Consult manual | ✔ IPX4 |
| Tank pre-charge | No (no integrated tank) | ✔ Yes — 70% of set point |
| Initial priming | Yes (consult manual) | ✔ 1.7 L (0.45 gal) |
| Time scheduling | ✔ Via app | Consult manual |
| Cyclic leak alarm | ✔ Via app | Consult manual |
Choose SCALA1 if…
You need greater flexibility or Twin configuration
- You need a Twin configuration for higher flow
- You want maximum control and customization via app
- The project has multiple pumps to manage
- You need advanced time scheduling
- You want cyclic leak detection alarm
Choose SCALA2 if…
You prioritize simplicity and quick installation
- You want the simplest possible installation (integrated tank)
- You need IPX4 rating for outdoor use
- The project is a standard single-family home
- You want to minimize external components
- You're looking for a compact, low-maintenance solution
9Free Grundfos Ecademy training — Course 40: SCALA2
Grundfos offers a free 3-module, 15-minute training course on its Grundfos Ecademy platform, dedicated entirely to the SCALA2 pump. It is part of the Domestic Pumps training pathway and is ideal for installers who want to get up to speed quickly.
Grundfos Ecademy — Course 40: SCALA2 Water Pressure Booster Pump
This course presents the applications and advantages of the SCALA2 water pressure booster pump, including the concept of perfect water pressure.
Official course content from the Grundfos Ecademy platform:
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SCALA2 features and advantages A quick analysis of SCALA2 applications, features and advantages. ⏱ 3 min 45 s
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Perfect water pressure Discover all the advantages of perfect water pressure and how it can increase comfort and well-being for home users. ⏱ 3 min 30 s
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How to install a Grundfos SCALA2 pump Learn to install the SCALA2 water booster pump as we guide you step by step through the simple process. ⏱ 3 min 48 s
10Frequently asked questions about Grundfos SCALA installation
The Grundfos SCALA1 and SCALA2 represent two of the best domestic water pressure boosting solutions on the market. Correct installation — with special attention to hand-tightened connections, proper priming and correct tank pre-charge — is the foundation for ensuring years of quiet, efficient and trouble-free operation.
Remember Grundfos's three fundamental rules: hand-tightened connections (never with a wrench), priming with 1.7 liters and tank pre-charge at 70% of set point checked once a year. With the Grundfos GO app, configuration, monitoring and installation documentation are completed in minutes from your phone.
For official documentation, downloads and technical support, visit grundfos.com. For free training, access Course 40 at Grundfos Ecademy.
