Pump Size Matters - Outdoor Boilers

By:Warren Walborn

Regarding pumps, remember to have the correct size of pump. We carry two standard sizes of pump. The larger pump is the standard for installation and it is a 1/6 hp pump. This pump is strong and powerful and will handle most applications.

The smaller pump is only 1/25 hp and will work for some home installations if the distance between the boiler and building is less than 75 feet and there are only 2 bottlenecks (such as one filter, and one heat exchanger). 

However, most home installations have three bottlenecks - a filter, a domestic hot water plate heat exchanger, and then a forced air heat exchanger. If you have three bottlenecks and/or more than 75 feet of underground pipe, stay with the larger 1/6 hp pump. Both pumps are available through our online store HERE.

When do you need MORE power than only ONE of our strongest 1/6 hp pump?  Good question. If you are pushing water more than 150 feet and going through more than three bottlenecks, you may need more power...BUT there is a right way to get that power, and many wrong ways!

DO NOT add a pump inside the building! This seems logical, but it does not work - this pump will get air locked and fail.  Also, DO NOT think you can use a larger pump.

The PROPER way to get more power, is to "Daisy-Chain" together two of our special 1/6 hp hydronic circulators. Two pumps are "Daisy-Chained" together by simply connecting them to one another so they boost one another and provide the flow strength needed. And they must be located together at the back of the outdoor boiler, so that they are always primed.

Also make sure that your pump is always mounted so that the pump shaft is level to prevent an air lock as follows:

If you have further questions, don't hesitate to contact the experts at Outdoor Boiler Care by clicking HERE.