On-Demand • Self-Paced

A Primer to Heat Pump and Air Conditioning Non-Invasive Test Procedures

Non-invasive testing reads system performance from temperature, airflow, and enthalpy measurements taken outside the sealed system — no gauges, no hoses, and no refrigerant lost to a set of connections. This one-hour on-demand training is a primer on how those procedures work: how to estimate suction and liquid pressures, superheat, subcooling, and approach without ever hooking up a manifold.

● 1 hour of self-paced content

Enroll in Non-Invasive Test Procedures

Diagnose system performance without hooking up gauges

It is the condensed version of ACCA’s HVAC System Performance Diagnostics class, taught live by an instructor who works every formula and example with you in real time.

HVAC technician performing non-invasive heat pump and air conditioning testing

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Why techs choose ACCA’s non-invasive testing course

Less system disruption

Assess performance and charge without using refrigerant gauges. Every set of gauges you connect is another chance to lose refrigerant, introduce contaminants, and create a callback you did not start with.

Faster diagnostics

Temperature readings get a tech to an answer without setting up a manifold, purging hoses, or standing around waiting on pressures to settle.

One hour, self-paced

Short enough to fit a slow afternoon or run as a team training session.

A decision rule, not a hunch

You leave with target values and acceptable bands, so “this one needs gauges” becomes a number you can defend to a customer or a manager.

Equipment you already service

Split-system air conditioners and heat pumps, from older low-efficiency units through today’s high-efficiency systems.

Who is this training for?

✓

Service technicians who diagnose heat pumps and air conditioners

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Maintenance techs running seasonal performance checks

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Techs who want a more structured approach to diagnostics

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Experienced techs adding non-invasive methods to their routine

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Service managers and quality-control leads who want one consistent diagnostic process across a whole team

What you’ll learn: enthalpy, approach, CTOA, and estimating pressures without gauges

Common system performance problems and how to work through them.
Superheat and subcooling charging methods, and when to use each, plus the total weight (weigh-in) method and other OEM-recommended procedures.
Calculating target superheat with the (3 × IDWB − 80 − ODAT) ÷ 2 formula, worked step by step.
The least-intrusive testing sequence: visual duct inspection, verified airflow, static pressure, and supply and return enthalpy.
Estimating evaporator saturation from return air temperature, and condenser saturation from CTOA + ODAT.
The Non-Invasive System Test (NIST): estimating suction and liquid pressures, superheat, and subcooling from temperature readings and a P/T chart, with nothing connected to the system.
Working through real-world examples and practicing how to interpret test results.

Training cost

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Non-Invasive Test Procedures FAQ

How long is the course?

One hour of online content, self-paced.

Does non-invasive testing replace using gauges?

No. These procedures are a diagnostic starting point. They tell you whether a system warrants a closer look before you connect to it. What the class adds is the target values and bands that make that call defensible, and a clear order of operations for what to check first when a reading falls outside the band. When OEM performance data is available, the OEM data always wins.

What tools do non-invasive test procedures require?

Accurate digital thermometers and clamp probes. You also need a way to read wet-bulb temperature, airflow measurement tools — such as a hot-wire anemometer, rotating vane, wireless airflow probe, or a capture hood — and a P/T chart for the refrigerant in front of you. The course explains what readings you need and where to take them. It also explains why measuring off the coil rather than at the grille changes the answer you get.

What equipment do these procedures apply to?

Split-system heat pumps and air conditioners. Coverage runs from older low-efficiency equipment through today’s high-efficiency systems — the CTOA targets you’ll learn are broken out by efficiency tier, and by manufacturer where the OEM publishes its own values.

Does the course cover target superheat calculations?

Yes. You’ll learn how to calculate target superheat and use superheat and subcooling to verify the charge. You’ll also learn to estimate superheat and subcooling without gauges at all, using return air temperature, CTOA, and a P/T chart.

Do I need to know psychrometrics to follow along?

No. The class covers what you need as it goes: what enthalpy is, why HVAC uses specific enthalpy in BTU per pound of dry air, and how to turn a wet-bulb reading into an enthalpy value you can actually use on a job.

Is this the same as ACCA’s HVAC System Performance Diagnostics class?

No. This on-demand training is the condensed primer. The full HVAC System Performance Diagnostics class goes considerably deeper and is available online and in person. This hour is a good way to find out whether that’s your next step.

Do I need equipment to take the course?

No. This is theory-based training. You’ll apply it on your own service calls. You’ll leave with the formulas, the target values, and the testing sequence ready to use on the next system you look at.