This guide answers "how do I test a mini split system" in measureQuick: which workflow to choose, where the probes go, and how to read the results. It applies to mini split, multi split, ductless, and VRF systems.

Mini-splits do not test like ducted systems: there is no liquid line at the head, superheat runs near zero, and the indoor unit gets its power from the outdoor unit. measureQuick has a dedicated mini-split workflow that accounts for all of this. Set it up right and the system will take longer to stabilize than the test takes to run.

1. Choose the workflow

Select the Mini-Split/Multi-Split/VRF workflow when starting your project. It is listed with the Classic Workflows; see the Workflow Comparison and Usage Guide. In your project details, set the equipment type to mini-split.

2. Put the system into a steady cooling mode

Mini-splits have many operating modes and you rarely know how the unit is rated, so force it to run continuously the way it was designed to run:

1. Set the unit to cooling, on.
2. Turn the setpoint down to 66 or 67 degrees so it runs the whole time.
3. Set the louvers to sweep and leave the fan on its automatic speed. Do not force high fan or turbo mode.

3. Place your probes

Activate your probes in the Toolbox before you start filling out the project so they stabilize while you work.

• Return air: set the probe on top of the indoor head, where it samples the air being drawn in.
• Supply air: clip the probe into the supply grille so the sensor sits up inside the supply airstream. A small binder clip zip-tied to the probe works well on the plastic grille. Make sure the back of the probe will not hit the louver as it sweeps.
• Suction pressure: at the outdoor unit's service port. Most mini-split service valves need a 5/16" core depressor adapter (three bands on the fitting mark it as 5/16"; available from AccuTools and others) to depress the Schrader and read pressure.
• Suction line temperature: clamp on the larger line at the outdoor unit.
• Outdoor air: place the outdoor air probe as usual.

Do not look for a liquid line. On a mini-split the metering device is in the outdoor unit, so both lines at the indoor head run cold. The small line is not a liquid line and there are no prescribed temperatures for it. You only measure the suction side.

4. Take one set of electrical readings

The indoor heads are fed by the outdoor unit, so you capture electrical readings once, at the outdoor unit. You do not measure each head independently.

5. Read the results

A few things that look wrong on a mini-split are normal:

• Superheat can run very low, often zero to one or two degrees.
• Suction pressure can look low compared to a conventional split system.
• The report will show N/A for high-side pressure, liquid line, and discharge line. Those measurements do not exist in this workflow, so the subsystem review carries a couple of N/As by design.

A green flag means the system is in the ballpark and running to its capacity. When you are done, save the data and exit with sync to cloud so the project is stored to your measureQuick cloud account.

Questions about a specific reading? Email support@measurequick.com with the project synced to the cloud so we can look at your data.