You will not be able to charge the system correctly plus you will have moisture stuck in the system.....
To test for leakage in the system.
If the system is being completely filled, a vacuum will have to be pulled on the system. If the system just needs to be topped off then a vacuum pull is not needed.
On a car's A/C system you should pull a vacuum to a -29 and it should hold for at least 30 minutes.
A deep vacuum can pull out air, water vapor, volatile oils, and other gases from a system. This helps to create a controlled environment with lower pressure, allowing for more effective processes like degassing, drying, or distillation.
You may have a vacuum leak or a check valve isn't working in the HVAC system. When there is no vacuum in the system it defaults to defrost. Under load the engine vacuum drops to almost zero. Normally the HVAC system has a vacuum reservoir to maintain operation during this situation, but if there is a leak it cannot hold vacuum.
Pull a vacuum
When changing out a compressor or condenser, you should pull a vacuum for at least 30 minutes to an hour, depending on the system's size and the amount of moisture present. The goal is to achieve a vacuum level of 500 microns or lower to effectively remove moisture and air. Using a vacuum gauge can help ensure that the system is adequately evacuated. Always follow manufacturer guidelines for specific requirements.
Pulling a vacuum on an ac system requires a vacuum pump or venturi pump with the correct type connector. The pump is connected to the low side ac port, and the vacuum could take an hour to pull depending on the pump size.
By expanding them, you create a vacuum inside them; given a portal (your mouth, nose), the vacuum will pull the ambient air in, just as a vacuum cleaner pulls things inside by creating a vacuum.
Pulling a vacuum in an HVAC system involves removing air and moisture from the system to create a negative pressure environment. This is done before charging the system with refrigerant to ensure proper operation and efficiency. Vacuuming helps in detecting leaks and preventing air or moisture from affecting the system's performance.
One good and quick way to check it is to pull the vacuum line off of it and see if there is fuel leaking into the vacuum system. If there is, the regulator is bad.
Typically, it is recommended to pull a vacuum on a refrigeration unit down to 500 microns or lower to ensure that moisture and non-condensable gases are removed, preventing any potential issues with the system in the future.