Do I Need to Vacuum a Mini Split?

You vacuum your carpeting, sure, and maybe your upholstery from time to time too, especially if it’s dusty. Yet your ductless mini split system? You weren’t aware that you had to vacuum that as well. Do you really?

Yes, vacuuming a mini split is crucial before refrigerant release. That said, it’s not a job you have to do yourself if you don’t feel comfortable. You actually need a special vacuum for this type of job and it does not need to be done regularly like your carpet would.  Your mini split technicians will gladly take care of this task for you.

Let’s discuss what the process entails now.

The technician will use tools such as Allen keys, a mini split adapter, HVAC gauges, and a vacuum pump. If not HVAC gauges, then your technician may utilize a micron gauge instead, but the tools are not interchangeable.

The technician will begin by inspecting the tools they are bringing to the job to ensure they are in working order. The valves will include two different pins which indicate high and low pressure. One of the pins is usually red and the other is blue, but that varies.

Next, they’ll connect the low-pressure valve of the gauge to the outdoor mini split compressor. The central hose should go on the vacuum pump. The technician will turn the vacuum pump on from there.

The pump will begin to run and develop a vacuum. This occurs gradually over 15 minutes depending on the system. As the vacuum appears, negative pressure will occur, and the gauge should display that in real-time.

Once the pressure turns negative, it’s time to turn the pump off and the gauge.

Vacuums are primarily used by technicians to do 2 very important tasks, remove air as well as humidity from the system. To do that, they’d follow the above steps as outlined.

The technician would wait for 15 minutes, then check the status of the vacuum. If the vacuum remains full, then your mini split system isn't leaking. Should the vacuum have started to deflate, then the technician would implement further testing to narrow down which component has a leak.

When the technician has found the culprit, they’ll let you know and recommend what you should do from there. In many instances, they’ll recommend mini split repair rather than replacement.

Vacuuming a mini split is not a regular occurrence unless you release refrigerant often. Otherwise, it will only occur that frequently or when you suspect leaks.

Failing to vacuum a mini split can affect more than the airtightness of your ductless mini split. The unit might not be able to accept refrigerant at full capacity, which can cause condenser pressure to go up and down because of the different condensable gases in the system. This strain on the unit affects how cool your home feels and may cause your condenser to break prematurely.

If moisture gets in the system to a damaging degree it will change the acidity in the oil, this moisture can linger. The moisture, when combined with the mini split’s lubricant, can create a chemical reaction that results in acid. The oil becoming acid, will remove the varnish in the electric coil inside the compressor and can bring the compressor to a ground