Why does it seem we are hearing a lot about dirt in hydronic systems lately? “Dirt” can mean ferrous metal particles, hard water deposits, metal shavings, solder, weld slag, sealing tape, even actual dirt and other things that find their way into the piping before it gets installed. All this dirt interferes with the operation of valves, circulators, flowmeters, anything with moving parts and heat exchangers.
Today’s high-efficiency hydronic system components could be the reason dirt has become such a popular topic. For example, dirt is less of a concern for a high-mass, low pressure drop cast iron boiler, but it’s a major concern with today’s low-mass, high pressure drop modulating condensing boilers. Just 1 mm of scale buildup on a heat exchanger can reduce efficiency by a whopping 10%! The heat exchanger water passages are small; it doesn’t take much dirt to completely clog one of these new boilers.
A related hot topic is the question of whether or not metal particles such as iron oxides are building up near the permanent magnets found in today’s ECM (electronically commutated motor) pumps. If so, is it affecting the life expectancy and efficiency of these high-efficiency pumps? In an ECM pump, the magnetic field is always present, not just when the motor is energized, as is the case with traditional PSC (permanent split capacitor) motors. Is this a problem? Are magnetic technology dirt separators the solution? Like I said, it’s a hot topic.
A well designed and properly installed/maintained hydronic system should contain very little dirt. We recommend:
→ NOT filling the system with untreated “hard” water (a topic for another article) and
→ INSTALLING a Caleffi DIRTCAL®, DIRTMAG®, DISCALDIRT®, or DISCALDIRTMAG® dirt separator
If your project includes primary/secondary piping, it needs hydraulic separation as well. In that case, check out the new, 4-in-1 SEP4™ hydraulic separator with air, dirt and magnetic separation for the ultimate in performance and lowest total installed cost.
We've got several videos that you may want to take a look at to help you in understanding dirt elimination:
For an indepth look at fluid quality and its effect on hydronic systems, it would be remiss of me if I did not share with you the following webinars from our Coffee with Caleffi archive: 1) Jeff Person's Fluid Quality and Its Consequences and 2) Air, Dirt and Pump Conflict.