Hydronic Pump Sizing

What You'll Need
Tape Measure

Hydronic pump heating is when water is used as a medium to transfer heat. This is where the water is heated up by burning gas, oil or using electric. The water then passes around the radiators or under floor heating systems where it gives up its heat to the air. Most hydronic systems require pumps to circulate water around the house. The right-sized pump is required to push water around your house—the bigger the house the larger and more powerful the pump you will need.

The Size of Your Home

Heating pumps are essential for all hydronic heating systems. Without a heating pump the water, won't be driven round the radiators properly.

Work out the number of radiators that you will need in each room by using calculations on the Internet. The number of radiators you have will depend on the size of your room. The bigger the room the bigger the radiator you will need. If you need any extra radiators then now would be the time to fit them in case you need a more powerful boiler or pump.

Number of Radiators

Now you will need to count the number of the radiators in your home so that you can work out the pump requirements. The more radiators you have in your home, the more powerful pump you will need. Don't forget to include under floor radiant heating systems which are run off your boiler.

Size of Connector

You will need to give the size of the pipes in your plumbing system some consideration. Pumps are available in a number of different pipe sizes. If you are replacing the pump to an older system then you might need to use various converters to change the size of the pipe.

Power of Pump

Most residential pumps are the same size although more powerful ones are available. There are complex calculators on the Internet which can be used to perform these calculations. It's always a good idea to buy a more powerful pump than you really need because the pump can always be made less powerful if required.

Balancing Your Pump

You should be able to adjust the power of the pump to balance your system. Ideally your boiler won't be shutting off until the water on the return feed is around 70 degrees. This will keep your home nice and toasty for a very long time.

The pump will affect how quickly the water can get from your boiler around to your radiators and under floor heating. The bigger the pump, the quicker this will happen.