At the same time, the circulator pump is constantly running without any feedback on hot water demand. “And, they want it now.” Klein is a strong advocate of The Metlund Hot Water D’MAND System, developed and marketed by Larry Acker, President of Advanced Conservation Technology, Inc. Metlund Systems. A water-pipe failure within these walls is virtually guaranteed to produce a cascade of costly consequences. In America, a typical single-family home wastes about 10 gallons of water a day—and that adds up to $11 billion per year in heating and waste-water treatment down the drain. The key to the system is to keep the volume of water in the branch lines as small as possible, eliminating standing water that accumulates and quickly cools in the pipes when hot water isn’t running. For temperatures greater than 140° F (60° C), follow recommendations by the manufacturer. But simply controlling flow velocity would eliminate the problem in the great majority of cases. Options include a bypass around the pump to reduce its effective output, a smaller-capacity pump, or a throttling/balancing valve downstream of the pump to restrict the flow, in addition to larger tube sizes in the areas affected. 1. Only products approved by the manufacturer for continuously operating systems should be used. On the other hand, the mismatch remains, and the potential for trouble exists should someone later decide to run the system at full capacity. Taco’s Hot-LinkPlus-e instant hot water system combines the easy-to-install Hot-Link® Valve with the 006e3® hot water circulation pump and the award winning SmartPlug Instant Hot Water Control®. Connected valves on the domestic hot water system, which are not modulating on a regular basis like in an HVAC system, can be exercised autonomously to ensure that they operate when needed. Kevin is an environmental sciences graduate from York University and holds an MBA from the Schulich School of Business, with various certificates from University of Toronto and the Canadian Society of Association Executives. Refer to the 2012 Ontario Building Code, Section 7.6.3.5 (see Figure 2), or to the AHJ in your location. by Kevin Wong, MBA, BSc, CAE, and Avishai Moscovich MBA, P.Eng, LEED AP. In most cases, though, the primary, or even sole, culprit is excessive flow velocity. Several choices for corrective action to eliminate the problem of erosion corrosion … On the low-pressure side we control the zone hot water conditions with a recirculating pump, a heat exchanger, and a balancing valve to collect all of the hot water and put it back into the hot water supply. If long-term contact is established between chloride-containing water and copper, chlorides were beneficial in delaying the corrosion of copper. Furthermore, cloud-connected IoT applications can save energy by adding night setback sequences at low demand periods via throttling down the hot water recirculation flow to a minimum. Under these unmonitored operation conditions, pressure, temperature, and velocity often creep up to exceed the manufacturer’s optimal working recommendations. Waterline corrosion is a type of oxidation process that can happen to materials in contact with water. Available in configurations for both new and existing installations, the system costs around $500 to install and reduces water waste by up to 95%, cutting operational costs to a bare minimum. By installing a connected flow meter and temperature and pressure sensors in lieu of the manual gauges, you can maintain the recirculation flow rate at optimal position and extend pipe life. If you turn on the cold water and get hit with hot water instead, you may actually have a problem with the bypass valve that’s a part of your hot water recirculation system, rather than the pump itself. assures readers that “corrosion can be mitigated if systems are designed so that velocities do not exceed 4 to 5 fps (1.2 to 1.5 mps) in circulating systems”, • The Canadian Copper & Brass Development Assn. Riverside County: (951) 467-4994. When water flows through a copper pipe, dissolved oxygen reacts with the copper to form a protective oxide coating. The pump is easily controlled with a simple user interface and multiple pump settings allow you to customize pump operation to meet your needs while maximizing heater efficiency. The Copper Tubing Institute (CTI) recommends 2–3 fps for hot water recirculation pipe. The penalty for ignoring that can be painful and costly for building owners and occupants alike. Traditionally, during building commissioning a circuit balancing valve is installed and set to allow design velocity in the recirculation line. In addition to reducing the flow, it is good practice to limit domestic hot water to an optimal temperature of 140° F (60° C), since increasing the temperature of potable water can substantially change its corrosive effects on materials. Connected valves can be exercised autonomously to ensure that they operate when needed. By Jose L. Villalobos, P.E., Founder and CEOV&A Consulting Engineers, Oakland, Calif. Understanding the changes to NFPA 70-2020, Designing flexible, safe labs: Electrical, power and lighting, Designing flexible, safe labs: Fire and life safety, Circular economy ideas are leading to better real estate investments, Designing flexible, safe labs: HVAC and plumbing, Top 5 Consulting-Specifying Engineer articles: December 11-17, 2020. both published the standard as long ago as the mid-1980s. When annual or periodic service is not kept, failed PRVs can cause havoc by allowing high-pressure delivery into loops and suites. The issue rarely shows up clearly because many of the overbuilt systems are routinely operated at less than their full design capacity for a variety of reasons, such as low initial occupancies or low demand for hot water. You just need a few gpm for recirculation and try to get rid of the softener on the hot water side. Sluggish hot water delivery is a problem that plagues owners and builders alike. The following water quality parameters will cause erosion at velocities below 5 feet per second. Do you routinely have to wait for hot water in the shower, or while washing dishes? Most knowledgeable designers recommend a minimum. According to AWWA, every valve should be exercised on a regular basis, but it is never done. Water velocity We have had several customers that experienced pin holes in the hot water and not recirculation outlets. Design all hot water recirculating systems to keep velocities below 2 fps. B. Chlorides are one of the common culprits for the corrosion of copper pipes. This permits hot water to reach most points in the building within relatively short periods of demand time. FOUNTAIN VALLEY, CALIF. (JANUARY 12, 2019) — New from Noritz America, the NRCR Residential Condensing Tankless Water Heater Series uses a fully integrated pump to keep hot water close to even the farthest outlet in the … For example, at a 400-unit North Bay Area condominium complex, corrosion damage caused massive dislocation and other inconveniences as well as extensive, costly repairs and reconstruction. However, if you have ever had to wait several minutes for the water coming out of the faucet to heat up, you may be interested in learning more about hot water recirculating pumps. Systems are installed without engineering guidance without engineering guidance AWWA, every should. 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