System Syzer is an HVAC tool that helps with piping system design. The application is based on the original plastic wheel calculator by designed by Gil Carlson of Bell & Gossett. It was first introduced in 1963 and has since been distributed to well over a hundred thousand engineers and tradesmen.

The tool is made up several different calculators. There is a calculator for friction loss and velocity through pipe based on your fluid conditions. Use it to determine the relationship between fluid temperature, system flow and heat/cooling load. There is a Cv tool that can help in multiple ways.

We have also bundled the Circuit Setter® / Triple Duty Valve calculator that is very handy for balance contractors. Use it during design to help predetermine valve settings and out in the field to determine flow through the valves based on pressure drop readings.

What’s New

Version 2.0.2

• Fix Circuit Setter bug where the "Settings" value would not reset to 0 when tapping the reset button.

Ratings and Reviews

3.0 out of 5
2 Ratings

2 Ratings

Reginald Hertsager ,

Has calculation errors

The Reynolds Number does not appear to calculate correctly for "Other" liquid definitions with user input viscosity and SG. Otherwise, this is a useful rough estimating tool.

DevilsPoet ,

Inaccurate compared to B&G class materials

App needs work. Compared to other modern apps the interface is old slow and lacks sophistication. For example, fields must be reentered often, and auto populate with values that must be backspaces to removed.

MichaelW_bg ,

Ebiz guy

Confirmed problem with 50% setting on Circuit Setters is fixed in the latest version.

Flow state causes confusion but is correct. There are three states for flow: laminar, transition turbulent and complete turbulent. Transition turbulent was shortened to just "transition" in the app. However, most engineers understand this state as simply "turbulent". Further confusion is caused since "transition" sounds like it is in the Reynolds range where you cannot reliably predict the flow state. The flow labels have been improved in the full windows version. The next app upgrade will clarify the flow state labels.


Xylem Inc.
6 MB

Requires iOS 8.0 or later. Compatible with iPhone, iPad, and iPod touch.



Age Rating
Rated 4+
© Bell & Gossett a unit of Xylem Inc.


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

More By This Developer

You May Also Like