hot water recirculation problems

Hot water recirculating systems are designed to supply users with nearly instantaneous hot water. They are now becoming a common amenity, particularly in large multi-family residential buildings and hotels where this type of convenience is expected. 

A recirculating pump is typically used in pumping hot water directly from a central water heater through a hot-water pipeline, most often made of copper. At the same time, it returns (recirculates) the water that has now cooled back to the water heater for reheating.

Modern systems now come with a timer that automatically turns on the pump at set or regular intervals, particularly during peak water usage times. 

If you have the convenience of a hot water recirculating system in your building, there are several problems that you are likely to encounter that can hinder your system from performing at its peak.


Hot water recirculation pumps are exposed to flow-accelerated corrosion, potentially a costly problem. The corrosion is normally caused by aggressive water chemistry or excessive flow velocity resulting in the pipes being eroded on the inside. Often, the most commonly affected areas are elbows, tees, and bends where the pipe walls can become so thin to the extent of eventually rupturing.

One way of fixing this problem is to install a pump with a lower capacity as well as reducing abrupt changes in the water flow directions. Choose a pump design that has a large inlet/outlet so as to prevent calcium deposits accumulation at the connections. In hard water zones, a stainless pump designed with a rotor sleeve and replaceable stainless cartridge will offer you a longer service. 

Excess Noise

You can experience noise problems in your recirculation pump especially after a power outage. This can be the result of air entering the system. To fix this common problem, it becomes necessary to ‘bleed’ the system allowing the trapped air to escape.

You can do this by opening the small air escape valve until when you begin to have water coming. You may need to repeat this on all the other valves.

The noise coming from your recirculation pump could also mean that the bearings are wearing out, in which case, you will need to replace the pump before it completely fails.

Low Flow Rate

Sometimes hot water recirculation pumps have small motors which are unable to produce sufficient head pressure. Of course, this negatively impacts the water flow rate. Some pumps may, in fact, not have ample power to activate a tankless water heating system.

Therefore, before installation, ensure the pump is compatible with the water heater to avert future failure.

Wasted Power

Today, most pumps have been designed to strike a good balance between meeting your hot water requirements and conserving energy. However, if you have an older pump model, wasted power could still be a problem.

A good option is to have your pump on a timer. This ensures it doesn’t turn on when no one is likely to be using hot water, like during the middle of the night.

It also possible for your recirculation pump to waste power if the return pipes have not been insulated properly allowing heat to easily escape. For this, consider engaging a good plumbing company to help in insulating the pipes.


Hot water circulation pumps are certainly not new as they have been used extensively in high-end hotels and restaurants for years. But it’s only recently that more homeowners have begun to take advantage of the great convenience, which explains why many are still facing the above common problems.

Before you consider having one installed, it’s important to think about these concerns and do your own research to identify which system is best for your particular needs.