The design of a domestic water recirculation system is critical for commercial and institutional buildings. Today, R. L. Deppmann launches a new resource to assist... READ MORE
Printer Friendly (PDF)
Domestic hot water systems should be designed to limit the risk of pathogen issues including Legionnaires Disease. Avoiding risk in the design of these systems... READ MORE
Printer Friendly (PDF)
“Dual Temperature Systems and Mixing Valves” “Performance Conditions of a Mixing Valve” Last week the R L Deppmann Monday Morning Minute article examined the addition of a mixing valve. Today we will examine the re-circulation system with dual temperature requirements and answer questions about the term “Performance Conditions” mentioned in the Lawler literature. [Read more…]... READ MORE
Printer Friendly (PDF)
“Addition of a Mixing Valve” During the last 6 weeks, the R. L. Deppmann Monday Morning Minutes concentrated on re-circulation systems where the supply temperature to the system was the same as the outlet temperature of the water heater. Today we will examine the addition of a Lawler master mixing valve in the system. [Read more…]... READ MORE
Printer Friendly (PDF)
High Rise Considerations The last article, part 5, showed an example of a high rise system with pressure reducing valves (PRVS) and the importance of the correct setting of the balance valves. The example we used showed balance valves with as much as 18 PSIG across them at a low flow. When a design starts to incorporate [Read more…]... READ MORE
Printer Friendly (PDF)
High Rise Considerations The last article, part 4, showed an example of a high rise system with pressure reducing valves (PRVS) and their effect on... READ MORE
Printer Friendly (PDF)
The last three articles outlined pump selection in domestic water recirculation systems. In general, these systems have low flow and low head pumps. What happens in a high rise with pressure reducing valves (PRV) in the hot water supply? The pressure reducing valve introduces a fixed pressure drop which must be added to the calculations. [Read more…]... READ MORE
Printer Friendly (PDF)
The purpose of the domestic water recirculation system is to delivery hot water near a fixture during times when there is no draw. If someone is using hot water in the next room or apartment or process; the hot water is near enough to your fixture so the hot water is delivered in seconds, not minutes. [Read more…]... READ MORE
Printer Friendly (PDF)
Let’s assume the domestic hot water supply is a total length of 1000 ft. That is the entire pipe on all of the floors. Let’s also assume an average of 15 BTU/hr/ft of loss through the supply pipe insulation. Now let’s assume the recirc piping is 300 ft total at an average of 10 BTU/hr/ft of loss. What flow rate is required for a 10 degree ΔT? What flow rate is required for a 5 ΔT? [Read more…]... READ MORE
Printer Friendly (PDF)
The R. L. Deppmann Monday Morning Minutes series will focus on the plumbing portion of the new construction and building facility business for the next few months. The topics will be domestic water recirculating systems, pressure booster systems, volume and instantaneous water heaters, and mixing valves. I’ve had 6 job site visits in the last 2 months to help engineers, service contractors, and facility managers solve problems with domestic water recirculating systems. It seems this is a good place to start. [Read more…]... READ MORE
Printer Friendly (PDF)

Categories