Common Objections to Automatic Balancing
Although the use of automatic flow regulators has continued to gain industry approval in the past years, resistance to their use still exists. Most resistance is based on misconceptions about their use or on outdated information. Following are several of the most common misconceptions along with practical responses.
Engineers Are Reluctant to “Fix the Flow”…
The tamperproof nature of the AutoFlow sets the design for the life of the building. It cannot be changed easily by well intentioned maintenance personnel. However, if the flow requirement changes, a different AutoFlow cartridge with a new GPM can be installed in a few minutes. It is especially easy on Models AC and YR where the cartridge can be installed without breaking the main piping. On new jobs, FDI will exchange up to ten percent of the cartridges at no cost.
They Plug Up…
AutoFlow valves don’t plug if they are piped as recommended with an inlet Y-strainer. The strainer also protects the coil and the ATC valve. The strainer is low-cost protection for these important components. Flow Design offers an inline strainer which can save space, but Y-strainers are generally recommended with a blowdown valve to ease servicing. The inlet strainer is recommended for sizes 1/2″ to 1″ and is encouraged for 1 1/4″ and up.
Typical Specification Drawing
And how AutoFlow valves apply in this application
They Waste Energy with Their High Pressure Drops…
AutoFlow valves add 4.6 feet to the calculated pump head. Circuit setter type devices typically add ten feet or more. The circuit setter requires manual devices on the coil, branch, riser and main. This series of units adds ten feet and many times 15 feet or more to the pump head. Because an AutoFlow regulator does not require the additional devices, it saves pump energy and the cost of supplying and installing the additional valves.
They Cost Too Much…
The typical 3/4″ complete coil piping Hook-Up, including the automatic temperature control (ATC) valve, costs the owner over USD $300 installed. An AutoFlow regulator adds approximately USD $25 to this Hook-Up (less than ten percent of the Hook-Up cost). This additional cost can be recovered with the reduced pumping cost achieved by lowering the operating head and preventing overflows. Using AutoFlow instead of manual balancing saves 1/2 hour of balancing time per coil and ten percent of the total pump BHP.