Saving time, money separating hydronic circuits

BY PAUL ROHRS,

contributing writer

The new kid on the hydronic street corner is a component called a hydroseparator or low-loss header. This is the first of a two part article that will look at the practical application of this component, how they are employed with mod-con boilers, and what value they bring to the hydronic table.

The hydroseparator is a component that keeps connected hydronic circuits separate from each other. You are probably saying to yourself that sounds like basic primary-secondary piping that we can achieve with closely spaced tees. The hydroseparator functions a little bit differently by creating a zone of low pressure loss so that the primary and secondary zones will remain independent from each other. Why do I need this component then? It is a potential time and material saver. In addition to isolating primary and secondary flow, it provides air elimination out of the top and sediment removal from the bottom. Let’s look at a few models that are on the market currently.

There are a couple of different types of hydroseparators on the market, including the 548 series from Caleffi, and one model available from  Precision Hydronic Products (PHP). Viessmann also has a low-loss header (LLH) on the market and it is my understanding that Taco is soon to introduce a model into their line of hydronic wares.

Installing a hydroseparator with a single boiler or single heat source might not be the best use of time and money unless you are considering adding optional heat sources in the future. Multiple modcon boiler installs or multiple heat source applications are really where the hydroseparators functionality starts to shine as they can increase profitability by reducing the amount of time and materials needed.  Previously, multiple mod-con boiler installs were piped in a reverse return or parallel primary fashion. This piping arrangement ensured equal return temps to each boiler and was ideal for establishing the heat sources for a primary-secondary system. You can see that it required a lot of time and material to correctly pipe this arrangement.

Let’s take a second look at the value of this hydroseparator. It provides air-elimination, sediment removal, gives us a platform for true primary-secondary piping, provides for reduced labor and material for hydronic systems, and can simplify the future addition of heat sources or secondary zones. If you remove the cost of your air-separator, wye-strainer, additional pipe and fittings, and the labor to install, those savings will go a long way in offsetting the cost of installing your hydroseparator of choice.

It is always appropriate to address concerns about utilizing space in mechanical rooms. Mechanical rooms are getting smaller. Space is at a premium right now and architects are trying to provide as much useable office or living space as possible. I can’t blame them for that. It does present a problem for contractors in that hydronic contractors are being asked to provide more heating options, more bells and whistles, and assemble them all in much smaller spaces. The hydroseparator is a great building block for assembly in small areas. We usually start our mechanical rooms by locating the boilers and making sure the venting will conform to the “total equivalent length” requirements if a modcon boiler is being installed. After that, mounting the hydroseparator seems to make our installs flow very smoothly.

One key aspect to be concerned about with sizing hydroseparators is the total flow rate. Check the literature and specifications prior to purchasing a unit so that you can ensure total secondary flow rates, often higher than primary side flow rates, can be met.

This would be a good time to discuss ever-advancing hydronic heat sources coupled with existing sources. Geothermal, solar, solid-fuel (wood, wood pellet, corn,) boilers, and modcon gas or lp fired heat sources can all take on a plug-and-play role as a hydroseparator allows ease of installation and integration. Hydronics have truly moved into the 21st century as significant advances have been made in the last five to 10 years. There can be 22nd-century advances lurking right around the corner that will have end users looking to integrate these advances as soon as they hit the wholesaler’s shelves. The hydroseparator would significantly simplify the new addition which we will take a more in depth look at in next month’s article.

Now that we have addressed the basics of the hydroseparator with the emphasis on piping of mod-con boilers, next month we’ll look at advanced and hybrid systems that integrate multiple heat sources on the primary side, as well as how the hydroseparator can be utilized with atmospheric boilers that require minimum return temps to prevent sustained flue gas condensation.                   

Contact Paul Rohrs via email at paulr@biggerstaffradiantsolutions.com.