What Is a Circulation Pump?

A circulation pump is the pump that enables hot water to circulate within the piping system in heating systems.

Thanks to these pumps:

• water heated in the combi boiler or boiler
• to the radiators
• to the underfloor heating pipes

is delivered, ensuring heat distribution at every point of the system.

The most commonly used pump brands are:

• Grundfos circulation pumps
• Wilo circulation pumps
• DAB pumps
• Lowara pumps
• Ebara pumps

Choosing the right pump and performing regular maintenance prevents pump failures.

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Circulation Pump Failures

The most common failures encountered in circulation pumps are as follows.

1️⃣ Circulation Pump Not Working

This is one of the most frequently encountered pump failures.

Possible Causes

• the electrical connection may be cut off
• the pump motor may have burned out
• control board failure
• jamming of the pump rotor

Solution

First, the pump's electrical connection should be checked. If the pump does not turn, the rotor should be checked.

2️⃣ Pump Runs But Does Not Heat

This situation usually indicates that although the pump is running, water circulation is not taking place.

Possible Causes

• air in the piping system
• clogging of the strainer filter
• insufficient pump flow rate
• blockage in the piping system

Solution

The air should be bled from the system and the filter should be cleaned.

3️⃣ Pump Is Making Noise

If the pump makes noise while running, there may be a problem in the system.

Possible Causes

• air inside the pump
• bearing wear
• rotor balance problem
• air inside the piping system

Solution

The pump should be bled of air and the system should be checked.

4️⃣ Pump Runs Continuously

In some cases, the pump may run continuously.

Possible Causes

• thermostat failure
• control system error
• temperature sensor failure

Solution

The combi boiler's control system and sensors should be checked.

5️⃣ Pump Consumes Too Much Electricity

Older-type pumps can consume high amounts of electricity.

Possible Causes

• old pump model
• fixed-speed motor
• operating under high load

Solution

It is recommended to use a new-generation inverter pump.

6️⃣ Pump Is Vibrating

If vibration occurs while the pump is running, there may be a mechanical problem.

Possible Causes

• rotor imbalance
• bearing failure
• piping connection error

Solution

The pump installation should be checked.

7️⃣ Pump Is Overheating

Excessive heating of the pump may indicate a serious failure.

Possible Causes

• motor strain
• lack of water circulation
• mechanical jamming

Solution

The pump should be turned off immediately and checked.

The Most Widely Used Circulation Pump Models

The models most commonly used in residential and central systems are as follows.

Grundfos

• Grundfos Alpha2
• Grundfos Alpha3
• Grundfos Magna

Wilo

• Wilo Yonos PICO
• Wilo Stratos
• Wilo Star RS

DAB

• DAB Evosta
• DAB Evosta 2

These pumps are preferred for their energy efficiency and durability.

How Long Does a Circulation Pump Last?

The average lifespan of a quality circulation pump is:

8 – 15 years

and can vary within this range.

However, the following factors affect its lifespan:

• water quality
• cleanliness of the piping system
• pump brand
• maintenance condition

How to Choose a Circulation Pump?

The following criteria should be considered when choosing a pump.

• flow capacity
• head
• energy efficiency
• system type

Choosing the wrong pump can cause failures.

Conclusion

Circulation pump failures generally result from the following causes:

• air in the piping system
• filter clogging
• pump wear
• electrical issues

Early detection of these issues increases system efficiency and extends the pump's lifespan.