Many new self-contained fractional horsepower refrigeration systems will be shipped from the factory with no service access ports. These systems will typically have a ¼-inch section of process tubing on both the high and low side that is pinched at its end. This will enable a technician to add an access port, if needed in the future, to measure the system’s pressure and to add or remove refrigerant from the system.
Many technicians will add some type of saddle valve to initially pierce the system and then either replace the saddle valve with a brazed Schrader valve or leave the saddle valve on the system. When the saddle is left on the system, there is a possibility for it to leak over time. They do not always leak, but the possibility does exist. However, to braze in a Schrader valve, some technicians will recover the refrigerant, braze in the new valve, evacuate the system, and add the refrigerant back into the system.