July 12, 2014

Why all the fuss about hydraulic separators? Closely spaced tees have worked just fine for me for 30 years... and it’s a cheaper way to go!

Hydraulic Separation, closely spaced tees

Yes, closely spaced tees do work and so do thermal storage tanks.  Let’s look at some facts about hydraulic separators (a.k.a. low loss headers, or de-couplers), closely spaced tees and tanks:

As stated in idronics #15:  "Any component, or combination of components, that has very low head loss, and is common to two or more hydronic circuits, can provide hydraulic separation between those circuits.”

A hydraulic separator reduces flow velocity, in the vessel, which allows for two secondary functions - air removal and dirt removal - in one device.  3-in-1 hydraulic separators make air removal and dirt removal primary functions, along with hydraulic separation, with no added piping connections or installation costs.  Magnetic dirt removal adds a fourth function to the above. Caleffi’s SEP4™ is available in sizes 1” to 2”.  Magnetic separation is especially effective for older system retrofits which can contain a high amount of magnetic iron and steel particles.

Closely spaced tees are easier to insulate and cheaper to buy (can’t argue with that) but they don’t necessarily save installation labor compared to hydraulic separators.
A system with closely spaced tees still requires air and dirt removal devices.

Locating a thermal storage tank between primary and secondary piping offers the added advantage of hydraulic separation, in addition to having a buffer tank. Separate air and dirt removal devices are still required.

Thanks for reading,
Kevin Freidt

Hydraulic Separation
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