Practical Guide
6 min 2026-10-28 Short answer: Brixon has 31 free field calculators for HVAC, refrigeration, hydronics, controls, electrical and plumbing work. They run in your phone browser, need no account, and show the formula behind every result. You can find them all on the free field tools page. They are estimates based on your inputs, so always verify against the manufacturer's data and the codes that apply where you work.
Most techs already do these numbers every day: target superheat on a fixed orifice system, mixed air temperature on an economizer, chiller tons from flow and delta T, voltage imbalance on a three phase motor. The math is not hard, but doing it on the back of a work order on a roof, in the wind, is where mistakes happen.
So we put the common formulas in one place. Type your readings, get the result, and see exactly how it was calculated so you can check it yourself.
Need a fault code instead? Try the free error code lookup or browse the fault code pages.
Enter indoor wet bulb and outdoor dry bulb to get target superheat for fixed orifice systems, then compare with your actual superheat from suction pressure and line temperature. For TXV systems, check subcooling against the manufacturer's target. Open the superheat and subcooling calculator.
Look up saturation temperature from pressure, or pressure from temperature, for common refrigerants. Some newer blends use approximate values, so confirm with the manufacturer's chart. Open the PT chart.
Enter outdoor and return air temperatures plus outdoor air percentage or airflows to estimate mixed air temperature, or work backward to find the outdoor air percentage. Useful for checking economizer operation. Open the mixed air calculator.
Get dew point, wet bulb, humidity ratio and enthalpy from two readings, plotted on a chart you can read on a phone. Open the psychrometric chart.
Enter the three line voltages to get the percent imbalance on a three phase supply. High imbalance can overheat motors, so compare the result with the motor manufacturer's limit. Open the voltage imbalance calculator.
They do not replace load calculations, wire or breaker sizing, or gas pipe sizing, and we did not build those on purpose. They cannot see the unit in front of you either. A number that looks wrong is often a bad reading, a sensor issue, or a system that needs a closer look.
Sometimes the readings are fine and the unit still trips. That is where Brixon's diagnostic assistant can help: describe the equipment, what you see and what you already checked, and it suggests free and easy checks first, with sources when available. It helps you narrow things down; you still verify on site. Your first question is free: ask Brixon.
Running a team? See Brixon for teams.
Yes. All 31 tools are free to use in your browser, with no account and no card.
No. The tools run in any phone, tablet or computer browser.
HVAC and refrigeration, hydronics, chillers and controls, electrical, and plumbing.
They are estimates based on your inputs and the formula shown on each page. Always verify against the manufacturer's data and the codes that apply where you work.
Most tools have an imperial and metric toggle.
Yes. It calculates target superheat for fixed orifice systems and actual superheat and subcooling from your readings.
No. Those are not included on purpose, because they depend on local codes and site conditions.
You can describe the problem to Brixon's diagnostic assistant. Your first question is free, and it suggests easy checks first with sources when available.
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