CircuitSolver Design Guide
Use this helpful design guide to calculate flow, pressure loss, and recirculation pump size for CircuitSolver systems. To download a printable PDF version of this guide, click here.
To determine pressure loss in the recirculation system, we recommend the use of traditional pipe sizing and head loss practices. Design guides published by ASPE and ASHRAE are widely accepted and recommended. The following guide is not intended as a design recommendation when specifying CircuitSolver valves, only as a guide to allow a plumbing designer to use any values of their choice.
Calculating Pressure Loss Across the Valve:
To calculate the pressure loss across the CircuitSolver®, use the “Design Cv” shown in the chart below. This Cv is typical for a CircuitSolver® valve under normal working conditions. Use the value that you calculate for the branch design GPM required to offset heat loss in the equation below the chart. Include that pressure drop in your head loss calculations for the circuit and pump sizing.
|CircuitSolver size, NPT||Cv fully open||Cv “closed”||Design Cv|
Flow rate calculation using Cv factor shown.
Recirculation Pump Sizing:
In a recirculation system, the pump must be sized to provide sufficient flow to compensate for the total heat loss in all the supply branches to the furthest fixture in each circuit. Heat loss in the return lines downstream of the CircuitSolvers is not included in the flow rate calculations.
The required flow rate formula is: GPM = BTUh/(ΔT X 500)
A common design practice for domestic hot water recirculation systems is to use ΔT = 5°F. This is the temperature difference of the recirculating water between the heat source and the furthest fixture in each circuit. If we assume this common value of a ΔT = 5°F, the above equation simplifies to GPM = BTUh/2500
If the designer prefers a ΔT = 10°F the above equation simplifies to GPM = BTUh/5000
Note that a higher flow rate is required if a smaller temperature drop is allowed. The BTUH heat loss will vary based on pipe type, size, length, and insulation. The BTUH heat loss table below is used only to demonstrate example calculations and should not be referenced for real world BTUH heat loss.
Calculate the recirculation flow rate required for ΔT = 5°F with 100 feet of ¾” insulated copper pipe, and determine the pressure drop across the CircuitSolver® at that flow rate.
Use the chart above for heat loss of 1800 BTU/h per 100 feet and the equation above for temperature drop ΔT = 5°F. Flow rate = 1800 / 2500 = 0.72 GPM flow required in that circuit.
Using a ¾” CircuitSolver® with Design Cv = 0.85: pressure drop = (0.72 / 0.85)² = 0.72 PSI Conclusion: Pressure drop across a ¾” CircuitSolver® with design Cv of 0.85 and branch flow of 0.72 GPM is 0.72 PSI.
Calculate the recirculation flow rate required for ΔT = 5°F for 200 feet of ½” insulated copper pipe, and determine the pressure drop across a ½” CircuitSolver® at that flow rate.
Use the chart above for heat loss of 1600 BTU/h per 100 feet (X2 for 200 ft.) and the equation above for temperature drop of ΔT = 5°F.
Flow rate = 3200 / 2500 = 1.28 GPM flow required in that circuit.
Using a ½” CircuitSolver® with Design Cv = 0.6: pressure drop = (1.28 / 0.6)² = 4.5 PSI
Conclusion: Pressure drop across a ½” CircuitSolver® with design Cv = 0.6 and branch flow of 1.28 GPM is 4.5 PSI.
Calculate the recirculation flow rate required for ΔT = 10°F for 200 feet of ½” non‐insulated copper pipe, and determine the pressure drop across a ½” CircuitSolver® at that flow rate.
Use the chart above for heat loss of 2300 BTU/h per 100 feet (X2 for 200 ft.) and the equation above for temperature drop of ΔT = 10F. Flow rate = 4600 / 5000 = 0.92 GPM flow required in that circuit.
Using a ½” CircuitSolver® with Design Cv = 0.6: pressure drop = (0.92 / 0.6)² = 2.3 PSI
Conclusion: Pressure drop across a ½” CircuitSolver® with design Cv = 0.6 and branch flow of 0.92 GPM is 2.3 PSI.
The Da Vinci Project - By using CircuitSolver® balancing valves, we were able to save both time and money. The start-up process was much faster by not having to manually adjust each valve. After installation, the system balanced itself and required no maintenance. Arturo Hernandez GJM Engineering in Los Angeles, CA
I try to have CircuitSolver® specified on as many jobs as possible due to the simplicity of it. Eric McTee Plumbing Designer at ME Engineering in Golden, CO
I would tell any contractor, building engineer, and mechanical engineer if you are looking at CircuitSolver®, it is simple, it is easy to use, and it works right from the get-go. Chris Watts Plumbing Service Manager at Braconier in Denver, CO
USC Villages Student Housing - By using CircuitSolver®valves, we saved time and money by not having to balance the system or make any adjustments. It made the process much easier and smoother. Richard Parker Plumbing Contractor at Pan-Pacific Mechanical in Fountain Valley, CA
We’ve used CircuitSolver®s exclusively now for several years in every application we can. Simply stated, the product is easy to install and works very well with no issues to date. Christopher Meurer Plumbing Operations Manager at J.C. Cannistraro, LLC in Boston, MA
When we install CircuitSolver® valves, it corrects the client’s hot water circulation problems, and everything operates as it’s designed. We are going to keep installing them. Jason Putnam Project Manager at Douglas ORR Plumbing in Miami Springs, FL
It usually takes 2-3 plumbers, 2-3 days to balance a system of this size, but by using CircuitSolver® this process was done instantly. Huge savings in terms of time and effort typically devoted to the balancing process. Stephan Thompson Plumbing Contractor at E.M. Duggan Inc. in Canton, MA
CircuitSolver® was able to automatically balance the system when engineers could not. Mark Wilmink MarkCo Plumbing in Florence, KY
Right after the installation the general manager went around the building and there was a noticeable difference with quick delivery of hot water. Andy Crossland Principal Mechanical Engineer at Crossland Engineering LLC in Honolulu, HI
Simply stated, CircuitSolver® valves are easy to install and work very well with no issues to date. They’re efficient and take the time typically required to manually balance systems at the end of the project out of the equation. Christopher Meurer Plumbing Operations Manager at J.C. Cannistraro, LLC in Boston, MA
CircuitSolver®, being that it is an automatic balancing valve, just makes the job of balancing an intricate hot water system that much easier. David Texter Plumbing Engineer at Browne Engineering in Cincinnati, OH
CircuitSolver® is a game changer in balancing DHWS and I would definitely use it as a standard in future projects. Matt Trevino Plumbing Engineer at DBR Engineering in San Antonio, TX
By eliminating the conventional method of using fixed flow balancing valves and installing CircuitSolver® valves instead we were able to resolve our lack of hot water in some sectors of the hospital issue instantly. André Renaud Building Consultant at Mental Health University Institute of Quebec
Using CircuitSolver® makes balancing the system so easy. The valves automatically adjust themselves, so you don’t have to check each valve once installed, and there are never any callbacks for issues. Arturo Hernandez GJM Engineering in Los Angeles, CA
The advantages of the system are an efficiently balanced system, saving time testing and balancing the system, lower utility bills and reduced water usage. Luke Holding Project Engineer at The Beck Group in Dallas, TX
CircuitSolver® makes balancing the system so easy. We don’t have to manually set each line or make any adjustments. We have had absolutely no balancing issues since we started up the system. Richard Parker Plumbing Contractor at Pan-Pacific Mechanical in Fountain Valley, CA
It was taking over a minute and a half to get hot water, and now it’s down to 15-20 seconds…also a huge conservation of water…it was a fairly simply retrofit. Robert Albanese Owners Representative for The Austonian in Austin, TX
CircuitSolver® valves are efficient and take the time typically required to manually balance systems at the end of the project out of the equation. We have started up systems in the afternoon to come in the next morning to find hot water perfectly balanced throughout all risers and zones. Christopher Meurer Plumbing Operations Manager at J.C. Cannistraro, LLC in Boston, MA
I haven’t come across another product like CircuitSolver®. Once you install the valves you never have to adjust them, unlike manual balancing valves where you have to balance every single valve you install. Richard Parker Plumbing Contractor at Pan-Pacific Mechanical in Fountain Valley, CA
CircuitSolver® is a great product. The valves automatically adjust to changing temperatures and pressure drops unlike manual and automatic balancing valves. Plumbing Contractor Production Plus Plumbing in Vista, CA
CircuitSolver® makes the initial startup so easy. When we turned it on, the valves balanced the whole system without us having to make any adjustments. We never have any issues when installing them in our projects. Plumbing Contractor Production Plus Plumbing in Vista, CA
Before CircuitSolver®, we would have wait times between 5-7 minutes for hot water on the higher floors. Since we have installed CircuitSolver® valves, we are getting hot water when we need it and have not had a single complaint. Robert Schrieber Maintenance Manager at Embassy Suites in Brunswick, GA
The University of South Florida - On startup of this install, the system automatically balanced itself in under 3 hours, all without manual labor thanks to CircuitSolver®. The plumbers actually went out a did another job, went to breakfast, and when they came back, the system was balanced. Mike Bishop V.P. of Engineering at RGD Consulting Engineers in Jupiter, FL
Rittenhouse Hill Apartments - We had a very complicated apartment restoration involving 47 risers. CircuitSolver® saved a lot of time, installed easily, used smaller recirculation pumps to save energy & wear, and continues performing well. Ron Miller President at Adelphia Plumbing in Philadelphia, PA