Boiler Pumps / Circulators

We have been selling pumps for use in hydronic heating for several decades and have probably sold more than 30,000 pumps. These are also called “Circulators” and that is the more accurate technical term, though most people just call them “Pumps”.

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. While we are happy to provide analysis of pump size needed, more than 95 percent of our calculations show that the 1/6 hp pump is needed. 

The smaller pump is only 1/25 hp and will work for only few 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 on this page below.

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. Remember, their goal is to “circulate” the water through the entire loop, and this “Daisy-Chain” configuration is the only method recommended by the manufacturer and all hydronic experts.

Pumps & Circulators Products

3 products

3 products

Frequently Asked Questions

What size pump do I need for boiler?

Almost all boiler applications require at least a 1/6 hp pump. Contact our technical support team for an exact calculation.

What is the best boiler circulator pump?

The best boiler circulator pump is our 1/6 hp circulator available at OutdoorBoiler.com!

How much does a circulator pump cost for a boiler?

Please see this page for boiler circulator pump prices.

How long do boiler circulator pumps last?

We at OutdoorBoiler.com started selling pumps in the early 2000s and almost every one of the more than 30,000 pumps we have designed and sold are still in operation. Only a few have been returned, but most of those were simply airlocked (installed incorrectly) and they were in perfect condition still.

How do I know if my boiler circulator pump is bad?

Read this article entitled “Is My Pump Working? I Need to Know

What does a circulator pump do on a boiler?

A circulator pump on a boiler pushes water in a big loop. The water is heated in the boiler, and the water releases that heat in other locations where the heat is needed. Water is the most efficient fluid for transferring heat from one location to another.