How FLOWLIMIT improves heating system balance

How FLOWLIMIT improves heating system balance

In this module about using FLOWLIMIT in Grundfos intelligent circulator pumps, you will learn how the flow-limiting functionality helps keep the right pressure and flow in connected zones, improving the overall system balance.

Welcome to this ECADEMY module about using the FLOWLIMIT functionality in Grundfos intelligent circulator pumps to balance heating systems in commercial buildings.

Flow commissioning of heating systems in commercial buildings can be difficult.
In fact, many systems are suffering from overflow or starvation, because commissioning of heating systems is often poorly done.


Poorly balanced systems and zones that suffer from too much or too little flow may lead to the building’s actual energy consumption exceeding the designed energy consumption and may result in decreased Delta T and lower end-user comfort.

So, it is worth giving the job high priority.
Using an intelligent circulator pump with a flow limiting functionality meets the challenge of balancing heating systems.
Grundfos FLOWLIMIT is an electronic flow commissioning and limiting functionality that helps keep the right pressure and flow in connected zones and improves the over-all system balance, even though it has not been properly commissioned.

In short: Installing Grundfos pumps with FLOWLIMIT will eliminate the need for pump throttling valves, because the pump can adjust flow to only what is needed without the assistance of a throttling valve.

As a result, system efficiency may improve significantly, because the pump may automatically adapt its performance in order to reduce flow, keep Delta T high and keep return temperatures down.

In addition, our intelligent circulator pumps include an integrated advanced commissioning wizard that is based on the type of application of which the pump is a part. Intelligent pumps and Grundfos GO Remote provide a step-by-step guide for correct pump setup and commissioning to ensure fast, simple and proper commissioning.
Let’s take a look at one of the very well-known challenges in heating systems in commercial buildings: flow commissioning of the system and zones.

With FLOWLIMIT enabled, the maximum flow can now be very precisely controlled by the pump, which makes system balancing much easier.
Take a look at the chart comparing the flow curves of a traditional pump and an intelligent circulator pump with FLOWLIMIT enabled.
While other pumps just keep going at full speed, the FLOWLIMIT functionality makes it possible to set a maximum flow limit. This means that the circulator pump will never exceed the design flow – regardless of pipe diameter and potential friction loss.
Bear in mind that calculating the flow is not the difficult part. It is the pressure loss that poses the real challenge. Using a traditional pump, it is a common mistake to conclude that the system characteristic is much steeper than it is in reality.

Now, take a look at the more level curve. As you can see, FLOWLIMIT enables a system characteristic that is much lower than before, which minimises the risk of system overflow and reduces the overall energy consumption.
Up until now, flow limits were upheld by means of pump throttling valves that have no direct connection with the pump and are unable to alter its flow.

Thanks to FLOWLIMIT, the throttling valves may be eliminated, making the system balancing much easier and system operation much more energy efficient. Excluding throttling valves also means that initial costs can be cut.
Finally, let’s turn to another great advantage of using intelligent circulator pumps in heating systems in commercial buildings.
These circulator pumps are compatible with Grundfos GO Remote – a handheld controller that enables remote pump set-up, control and monitoring.

One of the benefits in terms of balancing is the easy access to the FLOWLIMIT function using Grundfos GO Remote.

Open Grundfos GO Remote. Choose the correct circulator pump. Enable the FLOWLIMIT function and set the FLOWLIMIT to the desired level. And voila! Commissioning of a new system has never been easier.

Reports on the pump’s energy consumption and operation can also be created and shared electronically using Grundfos GO Remote.
"Let’s recap. While flow commissioning of heating systems until now has been a difficult task, the FLOWLIMIT functionality improves system balancing, because you can:

- Set a maximum flow limit to reduce the risk of overflow;
- Reduce initial cost by making pump throttling valves redundant;
- Achieve easy commissioning by using Grundfos GO Remote; and,
- Achieve energy savings.

This lets you increase your business potential due to greater focus on pump and system efficiency.