Circulation pumps in central heating systems circulate domestic hot water with an increased pressure so that a tap supplies hot water instantly upon demand. So, a circular pump is crucial to ensure a constant supply of hot water, and the pump woes can leave you, your family, and your tenants cold.
These pumps typically face issues like the motor not starting, processing unit failure, bad motor connection, display blank, and more.
In this article, we will learn about common reasons behind circulation pump failures, troubleshooting steps, and proactive maintenance tips.
Understanding Circulation Pumps
A circulation or circulator pump is a water booster pump that moves hot water around the heating system. In addition to residential use, these pumps have many other uses depending on their types.
Different types of circulation pumps are:
Centrifugal pump:
These pumps deploy centrifugal force to move fluid through pipes. They are ideal for large-scale applications involving a high volume of fluid, such as water treatment or irrigation.
Positive displacement pump:
It moves fluid by repeatedly enclosing a fixed volume with valves or seals and moving it mechanically through the piping system. The pumping can be driven by lobes, pistons, screws, vanes, or diaphragms.
Impeller pump:
These most commonly used pumps in heating systems have a simple structure consisting of a rotor and a casing. The ability to adjust speed helps achieve capacity adapted to the system’s requirements.
Variable speed pump:
These technologically advanced pumps provide the ability to adjust the rotation speed to optimize the pump’s performance according to the current conditions, ensuring energy savings.
Common Causes of Circulation
Pump Failures
Pump overheating
Overheating is the most common problem with pumps. It
can be due to several factors like:
●
Improper installation
●
Lack of maintenance
●
Clogged filters
●
Blockage caused by foreign
substances
●
Damaged bearings
●
Lack of lubrication or wrong
lubrication
●
Too high or too low viscosity
Overheating can lead to the failure of pumps, resulting
in costly repairs or expensive repairs or replacements. So, take action
immediately to avoid further damage.
Mechanical failures
A mechanical failure can prevent the pump from
functioning properly. The most common causes behind mechanical failures are:
●
Word-out bearings
●
Leaking mechanical seal
●
Impeller failure
Electrical issues
Electrical faults can also lead to circulation pump
failures. The most common electrical issues are:
●
Wiring problems
●
Power surges
●
Motor failures
●
Loose connectors
●
Rusted connectors
● Melted wiring or connectors
Troubleshooting Steps
Here is a troubleshooting guide to fix a failed
circulation pump and get the hot water flowing smoothly once again:
Visual Inspection: Checking for leaks, unusual noises, or vibrations.
If you hear unusual noises or vibrations, identify their
source. Is it coming out of the pump?
●
Grinding or grating noises
indicate a likely problem with the pump’s motor or mechanical parts. Turn off
the pump's power and consult its documentation before inspecting yourself.
Otherwise, contact the manufacturer or pump technician to inspect and fix the
issue.
●
Hissing, gurgling, rushing water
or other noises could be due to an airlock. Air in the system interrupts the
flow of water. You can try resolving it by setting a towel or bucket beneath
the pump to gather water spills. Now, turn off the power to the pump’s circuit
and adjust the bleed screw or valve. This will release any air from the system.
Once done, retighten the screw or valve and check if the issue has been fixed.
●
High-pitched noises often
indicate blockages. If bleeding air does not resolve the problem, the issue
could be due to gunk or mineral buildup. In this case, contact a professional
to clear the lines.
Flow and Pressure Checks: Verifying adequate flow rates and pressure
levels.
Check pressure, bleed pump, and liquid density. If
noisy, check the impeller. Some circulation pumps have adjustable flow and
speed settings, usually between 1 and 3, with 1 being the slowest and 3 being
the highest. If the water flow pipe and radiators are not hot despite the pump
running, you may need to adjust the speed and flow.
Electrical Testing: Ensuring proper voltage and current levels.
●
If the pump does not start or
intermittently shuts off, check the system for faulty wiring, a tripped circuit
breaker, or a blown fuse.
●
Check the voltage at the pump
terminals. Low voltage can be due to undersized or oversized wiring.
●
Check whether the circuit
breaker and fuse are working properly.
●
Water ingress or damaged
insulation on wiring can result in ground faults. So, inspect and resolve these
issues.
Temperature Monitoring: Detecting overheating issues.
Overheating is one of the most common causes of circulation pump failures. So, ensure proper ventilation, check for blockages, and make sure the pump is not running dry.
Preventive Maintenance Tips
● Regular Inspections: Establishing a maintenance schedule.
● Cleaning and Lubrication: Clearing debris and ensuring proper lubrication.
● Replacement of Wear Parts: Timely replacement of seals, bearings, and impellers.
● Protective Measures: Surge protection, proper grounding, and insulation.
As you can see, circulation pump maintenance can extend
their longevity and overall performance. If the troubleshooting steps listed
above do not work, we suggest contacting a technician or reaching out to the
manufacturer’s customer service. But first, try out the tips listed in this
circulation pump troubleshooting guide.
