How to Vacuum an AC System

Knowing how to vacuum an AC system may sound tedious, but it’s easy with a simple guide like this. Cleaning an air conditioning system comes with many benefits, such as removing air or moisture that may cause damage in the long run. Unfortunately, many homeowners don’t know how to vacuum the AC system.

As a homeowner, you must clean your air conditioner system more frequently to remove moisture or air that may cause long-term damage. Therefore, it should be your priority, especially during the hottest months when you regularly use your AC system. As a result, this will ensure that your air conditioner runs efficiently and safely.

The good news is that this guide explores everything you should know about vacuuming AC systems. You’ll learn how to vacuum an AC system in a few steps.

Why You Should Vacuum Your AC System

The primary purpose of vacuuming an air conditioner is to remove any air or moisture that may dampen the system. Moisture is one of the biggest problems in the AC as it reduces the system’s performance. Besides, water condensation in the AC system can cause it to freeze or even corrode the AC’s internal parts, causing long-term damage.

If you fail to clean your AC system, it will accumulate more dirt and moisture, causing several problems. First, the air conditioner’s efficiency will decrease and potentially cause health problems. The worst is that your AC will struggle to function, increasing your monthly energy bills. Thankfully, vacuuming the AC can save you from all of that.

How To Vacuum An AC System in Simple Steps

You can vacuum an air conditioning system using or without a vacuum pump. However, most homeowners prefer using the vacuum pump because it makes cleaning easy.

How to Vaccum Home AC System Using a Vacuum Pump

A vacuum pump can help remove moisture from your air conditioning system, allowing the AC unit to function effectively. Notably, it uses oil, which you must replace after every use. You’ll also need a wrench and manifold gauge hoses.

Here are the steps to vacuum an AC system using a vacuum pump.

Step 1: Turn off Your AC Unit

You must ensure that your air conditioning system is “off” before vacuuming it. Locate the “off/on” switch knob and adjust it to the “off” position. That way, it will be safer to handle the job.

Step 2: Remove the Service Valve Caps

Use a wrench to remove the service valve caps from the AC unit. Next, you can check the gold-colored valves on the refrigerant lines, where they enter the condensing unit. Most ACs have their valves located at the bottom of the backside.

Step 3: Hook Up the Refrigerant Manifold Gauge Set

Hook up the refrigerant manifold gauge hoses onto the AC’s service valve lines. Next, thread the valves onto their respective hoses by turning the valves in a clockwise direction. Next, ensure that the vacuum pump hose is attached to the larger, low-pressure port while the other hose is attached to the smaller, high-pressure line.

Step 4: Check the Level of the Vacuum Oil Pump

The vacuum pump oil helps to trap contaminants from the AC unit and protect the pump from overheating while running. So, check the oil sight glass to ensure your vacuum pump has enough oil. The oil level should reach the “fill line” or “oil level” line marked on the sight glass. Consider topping up the oil if the pump oil doesn’t reach the mark.

Step 5: Screw the AC Vacuum Pump Onto the Center Valve

In a clockwise direction, thread the last center hose from the refrigerant manifold gauge onto the vacuum pump’s intake valve. Then, switch on the vacuum pump while placing the manifold gauge valves in the “open” position. Any moisture or air trapped in the AC lines will start to exit through the pump’s exhaust valve.

Pro Tip: Place the AC vacuum pump onto a flat surface near the AC unit to ensure it functions efficiently.

Step 6: Track the Refrigerant Manifold’s Gauge Readout

Check the refrigerant gauge manifold set until the gauge reads 29Hg. Next, close each manifold valve and shut off the vacuum pump. Wait for around 20-30 minutes, then recheck the gauge reading to ensure it still reads 29Hg. If the level drops below 29Hg, there’s a leak in the refrigerant system, which you must fix promptly.

Step 7: Disconnect the AC Vacuum Pump

Disconnect the refrigerant manifold gauge from your AC unit and the vacuum pump from the refrigerant manifold gauge. Next, turn on your air conditioning system to confirm if it’s working correctly and efficiently.

How To Vacuum AC System Without Pump

If you have trouble using the AC vacuum pump, you can still vacuum your AC system without the pump. Here are the steps to follow when vacuuming your AC unit without a pump.

Step 1: Depress the Access Valve

With the compressor installed, and the high and low-pressure valves in place, switch on the compressor. Next, depress the high-pressure valve on the AC. When the pressure in the high-pressure valve hits the lowest point, close the valve and switch off the compressor.

Step 2: Charge the Low-Pressure Side

In this step, you need to charge the lower pressure side of the AC unit to around 14 psi. Next, monitor the high and low-pressure sides for approximately three minutes. That will help you ensure that the pressures on both sides are equal. 

Step 3: Depress the High-Pressure Valve Again

Once the pressures on both sides are equal, turn on the compressor and depress the high-pressure valve again. Monitor the low-pressure side, and when its pressure reaches the lowest point, close the access valve on the high-pressure side. Finally, switch off the compressor.

Step 4: Repeat Step 2 and Step 3

Charge the low-pressure side of the AC to around 14psi and wait for the pressures on both sides to equalize. Next, turn on the compressor and depress the high-pressure access valve. You’ll realize that the low-pressure side of the AC doesn’t go as low as it did in the other steps. Shut off the high-pressure side valve if it’s not releasing any gas.

Step 5: Charge the AC with Refrigerant

The last step to vacuum an AC system without pump systems is adding refrigerant to your AC. After that, switch off the compressor, and the system will be ready to function.

Final Words

Now that you know how to vacuum an AC system, never let your air conditioning system get damaged by air or moisture. You can clean the AC system using an AC vacuum pump or without the pump. However, you don’t have to perform this procedure yourself if you lack the necessary tools and expertise. Instead, let Direct Air help you.

Contact us today to discuss your AC vacuuming project with our HVAC experts.

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