Float VS Electronic Fill Valves

Fill Valves are the heart of a tank-level control system (making the control panel the brain).  There are two common types of fill valves, Float, and Electronic, used in commercial building tank fill applications.  While both can be effective, the electronic float valves (and paired controls) provide extended life through even wear, improved communication with the BAS, and ease of service. 

On this Tech Talk, we are going to cover the difference between the float style and electronic style fill valves for storage tanks. So in the city of Houston we have this code requirement where you have to go through an atmospheric storage tank before you add on a pressure boosting system.

To pressurize your building, you got two options on which type of fill valves, you would use for that tank. The style that’s been around for a long time, is going to be this one 2401 float valve from Cla Val using the 100-01 Hytrol valve, base valve configuration and we’ve got this CF1C1 Pilot assembly here that is controlling the water on, and off the valve to open and close it.Now, this is a mechanical assembly you got the float hanging down in the tank and literally just like the back of a toilet, you know, the float goes up the valve is going to turn off the flow goes down the valve is going to open up and refill the tank. Problem with these style valves is it’s mounted up on top of the tank it can be difficult and even dangerous to get in and service it and it’s all mechanical in terms of how you make any adjustments, how it turns on and off and when you have two of them, there’s no way to alternate which valve is the lead valve.

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Design Considerations for Pressure-Boosting Systems in Commercial Buildings

Design Considerations for Pressure-Boosting Systems in Commercial Buildings

More than 60 years ago, the late Dr. Roy B. Hunter developed a system for calculating water loads in commercial buildings. The estimated water demand of fixtures (water closets, sinks, etc.) is given a value called Fixture Units which have an equivalent demand load in Gallons Per Minute (GPM). The Fixture Units and Demand Load relationship is known as Hunter’s Curve and is still the basis for plumbing system design today.

Hunter’s Curve can be effectively used to calculate total system demand, but it has a glaring flaw. There is no consideration for diversity in the system demand. Using Hunter’s Curve for the basis of design of a Pressure Boosting System results in a pump system sized for all fixtures being used simultaneously, a scenario that will likely never happen. The pumps are grossly oversized for partial-demand conditions which make up 90% or more of total operation, causing poor system control and unnecessary wear on the pumps and piping system. In addition to Hunter’s Curve, Cougar USA uses field experience and data collection for system design.

To generate an accurate demand load profile, we gather as much information as possible about the building. The type of building has a huge impact on the load profile; even with similar fixture units, hospitals, hotels, schools, and office buildings will all have different load demands throughout the day and week. Special applications, the height of the building, locations of equipment, and potential future expansion are all factors in creating the right Building Load Profile. Once the system requirements are determined, we must make the right equipment selection.

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