ALPHA CS control modes

Gain a workable knowledge of the different control modes for the ALPHA COMFORT SYSTEM and how they work.

In this module, we will introduce the control modes for the ALPHA COMFORT SYSTEM. You’ll gain a workable knowledge of what the different control modes are and how they work.

The ALPHA COMFORT SYSTEM is designed for domestic hot water recirculation systems without a dedicated return line and has 2 primary control modes:
24/7 Mode And AUTOADAPT

Additional control modes are available in the Grundfos GO app.

Let’s start with 24/7 Mode.
24/7 mode consists of 3 different settings: I, II, and III. You can set this control mode on the pump display by selecting the 24/7 icon and using the arrows on the display to select set point I, II, or III.
24/7 mode operates in constant curve 3 with flow limits that are designed for the different pipe sizes shown here. Each flow limit ensures the average velocity is limited to 2 ft/s for each pipe size.
This helps decrease noise… and the risk of flow accelerated corrosion, which can lead to pinholes.  This control mode ensures maximum comfort for the homeowner… and increases the reliability of the hot water supply system.

Flow Limit I is suitable for a ½” pipe. When the 24/7 icon is selected with Flow Limit I, the ALPHA COMFORT SYSTEM will run at full speed until it hits a max flow limit of 1.2 GPM – the recommended flow limitation for this pipe size.
Flow Limit II is suitable for a ¾” pipe and Flow Limit III is suitable for a 1” pipe.
When the 24/7 icon is selected with Flow Limit II or Flow Limit III, the same control method will be applied with a max flow limit of 2.3 GPM or 3.8 GPM, respectively.

Now let’s look at AUTOADAPT… AUTOADAPT also operates in constant curve with flow limits… but will lower energy consumption by automatically reducing the ON time of the pump.
The pump will learn when the comfort valve is closed based on changes in power and flow. This process occurs in 2 states: The Learning state and the Operation state.

In the Learning state, the pump power level is continuously analyzed as it operates in a 5-minute ON… and 15-minute OFF cycle. The pump will learn the signature of a closed valve by monitoring the minimum power level.
The pump will operate in the Learning state for at least one hour until it establishes a minimum power level. Once the Learning state is complete, the pump will move into the Operation state. In this state, the pump will know when the comfort valve is closed based on the minimum power level it obtained in the Learning state. When the pump detects that the valve is closed, it will turn off to further reduce energy consumption. The pump will turn back on after the 15-minute OFF cycle to ensure hot water is always available at the tap.

When using the AUTOADAPT control mode, the ALPHA COMFORT SYSTEM will run at full speed with 1.2 GPM max flow until the comfort valve closes. This flow limit is designed to reduce the risk of pinholes. If needed, the flow limits can be changed via the Grundfos Go app.

A common issue in typical systems without a dedicated return line is some bleed-over at the furthest tap.
With AUTOADAPT, the amount of time the pump is running is reduced, resulting in less hot water bleed-over, which ultimately delivers more comfort to the homeowner.

That covers the ALPHA COMFORT SYSTEM control modes and how they work.

Course overview

Modules: 8
Completion time
Completion time: 40 minutes
Difficulty level
Difficulty level: Intermediate