When designing the pipe, it is necessary to chose a fluid velocity to have good compromise in between pressure drop and economics, some recommendations are given below.

Hotwater recirculating pumpwith return line

Top 5 Most Popular  1. Pressure drop 2. Reynolds Number 3. Pressure drop K coefficients 4. Churchill equation 5. Moody diagram

Best hotwater recirculating pump

A hot water recirculating pump is great for convenience and comfort, as it means getting hot water faster when you turn on the hot tap. For homes with on-demand or tankless water heaters, this is important, as it can otherwise be a little bit of a wait before the cold water clears out of the pipes and the hot water reaches you. When a hot water recirculating pump starts having or causing problems with the system, though, it can become more frustrating than anything else, especially if you don’t know what to do about it. Here are a few signs there is a problem with your hot water recirculating pump, and what to do about it.

You can access to an Excel calculation tool in order to calculate the velocity a fluid in a pipe, knowing the pipe diameter and the fluid flowrate  : Fluid velocity in pipe Excel calculation tool (click here)

The information on this website is for informational purposes only; it is deemed accurate but not guaranteed. It does not constitute professional advice. All information is subject to change at any time without notice. Contact us for complete details.

Hotwater Recirculating pumpwith temperature sensor

Note that the velocity will be constant for a non compressible fluid but will vary with a compressible fluid such as a gas. For a gas it is therefore necessary to slice the pipe layout in several sections in order to recalculate the velocity along the pipe.

Warning : this calculator is provided to illustrate the concepts mentioned in this webpage, it is not intended for detail design. It is not a commercial product, no guarantee is given on the results. Please consult a reputable designer for all detail design you may need.

A hot water recirculating pump is supposed to make your access to hot water more convenient, not less. If you notice one of these signs that your recirculating pump isn’t performing at its best, call Maeser today. One of our experienced technicians will get you back up and running as soon as possible.

Hotwater recirculating pumpwithout return line

The fluid velocity in a pipe is a fundamental data to calculate to be able to characterize the flow in a pipe, thanks to the Reynolds number, and size a pipe circuit calculating the pressure drop expected for a certain flow.

If you turn on the cold water and get hit with hot water instead, you may actually have a problem with the bypass valve that’s a part of your hot water recirculation system, rather than the pump itself. The valve is designed to close and keep the hot water in the pipes once it’s up to temperature. When it cools down too much, the valve opens and the pump pushes the water back into the cold lines, making room for freshly heated water in the hot pipe. If you have hot water in the cold side, on the other hand, the valve may actually be staying open when it shouldn’t be.

Tankless hotwater recirculating pump

Hotwater recirculating pumpinstallation diagram

These values are given as an indication for pre-sizing. Each company should have its own guideline to be followed.

In addition to the sources given below, one may also wish to consult Applied Process Design for Chemicals and Petrochemicals plants, Ludwig, Gulf, page 85 which is giving values for specific applications like sodium hydroxide, ethylene, vinyl chloride...

Our site uses cookies and other technologies from 3rd party companies. Access our Privacy Policy in the "About" page to know more about those cookies and technologies . Further use of this site will be considered consent.

The purpose of a hot water recirculation system is to provide you with hot water faster, so if you find yourself waiting for hot water when you turn on the tap, there could be something wrong with your system. Here are a few potential problems:

With : Q = Volumetric flowrate (m3/s) D = Pipe diameter (m) u = Fluid velocity in pipe (m/s)

Like with most things, a lot of noise coming from your hot water recirculation pump isn’t a good sign. Once again, there are a few different things it could be.