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What is a Circuit Setter? (Types & How To Install)

A circuit setter is used in plumbing, but do you know what it does, what types are available, and how to install and use one?

A circuit setter is a valve used in plumbing to regulate water flow. It is essentially a ball valve with a means to adjust the amount of opening you want. It is usually opened fully at first and reduced a little to restrict flow. It is reduced to the extent that it provides the right flow balance, suitable for the heating requirement.

I will cover more below.

The Circuit Setter

The circuit setter was invented by Bell & Gossett to ensure a balanced and optimum water flow.

It was introduced particularly in the HVAC industry also to provide accurate measurements. The velocity constant (CV) of each set is known. It usually ranges from 40% to 100%, but larger ones can adjust the flow between 0% and 100%. This makes it a type of calibrated balancing valve.

Although not so common in residential homes, it can be useful for homeowners, and various types and sizes are available. The sizes typically range from ½” to 3”, but ball-style ones can be as large as 4”, and globe-style ones as large as 12”.

Replacement for Manual Balancing Valves

A circuit setter is a replacement for a manual balancing valve.

Using a circuit setter, you won’t need to adjust a valve by hand manually. Another key distinguishing feature is the auto shut-off mechanism, which can shut off the supply to a part of the house when it is not used to save water and energy.

Types of Circuit Setters

Here are some samples of the various types and sizes of circuit setters available:

  • Circuit Setter Plus
  • Ultra Setter
  • Circuit Sentry
  • Circuit Sentry Flo-Setter

Circuit Setter Plus

circuit setter plus

The Circuit Setter Plus is specially designed for proportional system balance.

It is meant to assure optimum flow balanced at minimum horsepower. It is ideal for creating a balance HVAC and establishing a potable water system to maintain a low requirement of pump energy. The adjustable valve usually has an indicator and can shut off the supply.

Ultra Setter

ultra setter

An ultra-circuit setter is designed for improved control.

It usually has automatic control for temperature, independent pressure, and constant flow. It provides better comfort and can also save energy costs.

Circuit Sentry

circuit sentry

A circuit sentry is designed for several functions: flow balance, precise measurement, flow meeting, and shut-off.

It can also be a cost-saving valve.

Circuit Sentry Flo-Setter

circuit sentry flo-setter

A circuit sentry flo-setter is recognizable by its external lock handle to allow flow adjustment.

This can ensure a constant water flow and usually has an isolated valve option.

Using a Circuit Setter

A circuit setter can be used in two main ways: As a balancing valve and flow meter. (1)

Installing a Circuit Setter

A circuit setter is usually installed at a junction of a water pipe network.

Also, it is usually placed on the return side so that you can easily check, for example, the pressure drop, return pressure, supply pressure, rate of flow, and so on. This location is suitable because potential air and noise issues are reduced.

Note that a circuit setter is unidirectional, so it must be installed in the direction of the arrow shown on the valve’s body.

Using a Circuit Setter as a Balancing Valve

As a balancing valve, the valve plug is set to adjust the water flow rate in the system.

Different settings are possible, each with a specific GPM (Gallons Per Minute) and ΔP (Change in Pressure). After balancing the system to the required flow rate, the memory pointer is set and clocked to that setting. Once set, the valve can be closed fully but not opened beyond its locked setting.

Using a Circuit Setter as a Flow Meter

You must attach the differential pressure gauge to the pressure taps to use a circuit setter as a flow meter.

This makes it possible to determine the ΔP. The GPM is then determined by the circular slide rule (provided by the manufacturer). The GPM reading on this rule depends on the valve’s degree setting, the valve size, and the ΔP value of the water (per foot).

(1) Leo A. Meyer & H. Lynn Wray. Instruments for HVAC work: Indoor environment technicians library. HVAC Books – Best on the Web. 2003.

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About Sam Orlovsky

AvatarCertifications: B.E.E.
Education: University Of Denver - Electric Engineering
Lives In: Denver Colorado

Electrical engineering is my passion, and I’ve been in the industry for over 20 years. This gives me a unique ability to give you expert home improvement and DIY recommendations. I’m not only an electrician, but I also like machinery and anything to do with carpentry. One of my career paths started as a general handyman, so I also have a lot of experience with home improvement I love to share.

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