Are you wondering how to vacuum a car AC system without a pump? Do not worry, you can. The process is easy but is less efficient compared to using a pump.
Dust, air, and moisture accumulation in the AC system can reduce performance and other malfunctions. For example, if moisture exists in the refrigerant, it will react with the lubricant in the system to form an acid. This process can then cause rust and fail the motor windings.
This article will take you through a step-by-step process to vacuum a car AC system without a pump.
How to vacuum car AC system without pump
The purpose of this entire procedure is to ensure you have removed all air and moisture in the vehicle’s AC system to avoid a decrease in performance. The process will also help extend the lifespan of your air conditioning system and prevent any future expensive repairs.
Regular service maintenance should involve the steps below since they help keep the system in perfect condition for your comfort. Therefore, make sure to do the processes yourself or tell your local mechanic to undertake them the next time your vehicle is in the shop.
You will need a manifold gauge set and a compressor for these steps.
Step 1: Depress the access valves of the AC system
Take the manifold gauge and install the access valves to the compressor. Do this to the high side valve and the low side valve. Start the pressurization process by depressing the high side access valve and observing the pressure at the low side.
Ensure that the pressure on the low side valve is as low as it can get. Once the pressure is confirmed to be as low as it can get, the high side access valve will close due to pressure build-up and shut off the compressor.
Step 2: Charge the low side valve
Use the low side access valve to regulate the pressure on the low side to 14 psi. Proceed to observe the pressure readings on both the low side gauge and high side gauge for a couple of minutes. Both pressures will read the same thing after a few minutes indicating a point of equilibrium.
Step 3: Disconnect the high side valve pressure
Proceed to repeat a similar process to step 1 by turning on the compressor and disconnecting the high side access valve. Observe the pressure reading on the low side gauge to ensure it gets as low as it can. The high side valve will then close due to pressurization once the pressure is as low as it can get on the low side. Go ahead and shut off the compressor.
Step 4: Do steps 2 and 3 again
You can now go ahead and repeat steps 2 and 3 to see if you have successfully evacuated the air and moisture in your Ac system. You will know you have efficiently vacuumed the system when the low side pressure does not go as low as it did in the prior tries. It will indicate that the refrigerant is released gradually and getting absorbed in the compressor oil.
Additionally, proceed to cut off the high side valve in case air or moisture is not getting expelled through it. This will indicate that all the moisture and air have been successfully evacuated.
Step 5: Charge the Refrigerant for the AC system
As with any AC system repair, you will need to charge the system with refrigerant to get it to the manufacturer’s specific levels. Pump the AC specific refrigerant into the system to the indicated level and finish off by shutting off the compressor.
What happens if you don’t vacuum your AC system?
It is essential to vacuum the AC system because you want to remove any air, dust, and moisture in the system that will inevitably reduce the AC system’s performance. Not only that, you need to vacuum the system before you refill it with fresh refrigerant to prevent the same substance accumulation.
So, how does the air and moisture build-up in the vehicle’s AC system affect performance and cause malfunctions? You want refrigerant and oil to be the only thing in your vehicle’s AC system. Other inclusions will damage it, and that is why the hoses, pipes, and seals are well made to keep a tight seal.
Moisture accumulation is by far the most severe and common problem when it comes to the air conditioning system of your car. You can easily introduce moisture into your system if you have a leak in the AC or you recently opened the system up.
This is to say that any time your AC system is opened, moisture and air can get in. The air and moisture can get into the system via an opened valve cap or when you are installing the can. Vacuuming the system regularly and during AC system maintenance is thus crucial in keeping the air and moisture out.
Another way moisture and air can get into the system is during an accident that breaks the vacuum lines or the condenser. Air from the surroundings will enter the system through the broken parts and add moisture.
Moisture does two things to the system:
- Corrosion – the moisture will cause rust formation when it gets in contact with the lubricant oil. The reaction between the two corrodes the AC system’s internal parts and will lead to malfunctions and component damages.
- Ice formation – ice will form when the moisture gets into the expansion valve. The moisture causes a blockage at the valve because the expansion process results in water condensation. Moisture will freeze at this point and form ice that blocks the expansion valve to reduce the performance of the AC system.
Air, on the other hand, affects the AC system by:
- Occupying space meant for the refrigerant – air is a non-condensate gas that will occupy space meant for the refrigerant. The air will reduce the condenser capacity since the condenser cannot accommodate both the refrigerant and air. Moreover, more refrigerant won’t be charged into the system since the air is taking up some space.
Since the condenser capacity is reduced, the temperature and pressure in the system will increase. The temperature increase will cause the condenser to overheat, which means there will be more power usage. Eventually, the condenser will malfunction due to overheating and overload.
As you can tell, you do not need a vacuum pump to vacuum your vehicle’s air conditioning system. The main thing to remember is that the vacuuming process should be done regularly to avoid potential problems. Air and moisture build-up in the AC system is a crucial aspect to keep in mind since it can lead to expensive repairs.
1. How long should I vacuum my car AC system?
On typical occasions and maintenance services, you should vacuum your car’s AC system for about 30 to 45 minutes. That is plenty of time to ensure that all the gases and moisture in the system is completely eliminated.
However, the process may take a shorter time, say 10 to 30 minutes depending on the amount of build-up in the AC system. The vacuum pressure reading for an efficiently vacuumed AC system should be about 29 inches or 27 Hg.
2. How often should you vacuum your air conditioning system?
The recommended timeline by professionals is usually once per year, especially during the spring. Most mechanic shops and car manufacturers recommend you vacuum your vehicle’s air conditioning system every time you take it for regular maintenance service. The regular maintenance schedule will help eliminate any air or moisture build-up in the AC system that may be affecting its performance.
However, you do not have to wait till your maintenance date to vacuum your car’s AC system. If your AC system starts to decline in performance and experiences malfunctions, then it may be time for you to vacuum it.
3. How much vacuum do you need for the AC system?
According to most manufacturers and professionals, the appropriate vacuum needed to remove all air and moisture from the system is about 27-29.92 Hg. The air conditioning system of your car needs to hold a vacuum of 29.92 Hg for at least 1 minute to be considered efficient.
4. Does vacuuming AC remove oil?
The process of vacuuming the air conditioning system only evacuates air and moisture from the unit. It does not affect the levels of oil or any other substances like debris or refrigerant. You will need to use a separate process to remove lubricant oil from the air conditioning system.