Category: Plumbing

Heat Pump Water Heaters: Performance at Varying Ambient Temperature

I recently received two graphs from AO Smith that show the difference in performance for their residential heat pump water heater, the Voltex.  A lot of manufacturers print performance at one condition.  The charts below shows the difference across the entire range. This data reiterates the importance of climate. Images Courtesy of AO Smith




AO Smith Optimizes Tankless Product Line, Discontinues ATIO-710

AO Smith, America’s largest water heater manufacturer, has stopped production of the ATIO-710.  Jeff Ogan, Product Manager of AO Smith’s On Demand Products, wrote in a note to representatives that “the performance of the ATI0-540 condensing heaters is a perfect, high-efficient replacement for the 710 series”.  He goes on to add that the flow rate…




2015 U.S. Department of Energy Solar Decathlon

An engineer friend of mine brought a competition to my attention today.  It’s called the U.S. Department of Energy Solar Decathlon.  To briefly summarize the history and purpose of the competition – The first competition took place in 2002 and has been ongoing biannually.  Roughly 20 university-led teams compete to design, build, and operate a solar powered…


Tags:


How to Size a Boiler for Indirect Water Heaters

Sizing a boiler plant that will handle both space heating and domestic hot water is not a tricky task, but it also isn’t as easy as adding the two loads (space heating + domestic water) together.  I embedded a short slideshow that illustrates a straightforward method from ASHRAE’s standards.  This standard is more crucial for…




How the New NAECA Regulations Affect Water Heaters

The National Appliance Energy Conservation Act (NAECA) was first enacted in 1987 to set minimum energy efficiency standards for certain household appliances – refrigerators, freezers, room air conditioners, clothes washers, dishwashers, ovens, and water heaters.  Since 1987, revisions were made in 1990 and 2004.  On April 16th, 2015, new regulations under NAECA will go into effect…




How to Properly Support PEX for Distribution Piping

Polyethylene cross-linked (PEX) tubing is making its way into the larger diameter hydronic and plumbing distribution applications.  Although most commonly associated with radiant floor heating and diameters under 1″, some PEX manufacturers now have 20ft. straight length pipe available up to 4″.  Replacing copper with PEX is a great way to save material and labor costs.  Although…


Tags:


Rinnai Releases New Tankless Water Heater with Built-In Recirculation

According to a press release by Rinnai, a leading manufacturer of gas applicances, two new products are being introduced to their Condensing Tankless Ultra Series.   Known as the “RUR” models, the RUR98e and RUR98i are both 199,000 BTU/hr input.  The “e” designates outdoor installations, the “i” for indoor installations.  The biggest features that Rinnai…