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Refrigerant Line Pressure

Refrigerant line pressure measurement can be used in establishing the operating conditions of a compression-cycle heat pump or air conditioner, and in determining whether the system may have a refrigerant over-charge or under-charge. Refrigerant pressures may range up to 500 psi and even higher for some refrigerants (e.g., up to 800 psi for R-410a).

Application Notes

Any connection to a refrigerant system must be done by a trained and certified technician. U.S. Environmental Protection Agency (EPA) regulations covering ozone-depleting materials (including CFC and HCFC refrigerants) require technician certification for almost any type of work on systems (e.g., attaching and detaching hoses and gauges to and from the appliance to measure pressure within the appliance).

Most technicians working on refrigerant systems carry gauge sets for on-site pressure measurement but are not equipped to install pressure transducers for longer-term monitoring. It is important to determine the type of fittings available on the refrigerant lines and pressure transducers in advance, to find fittings that allow a positive and leak-free connection, and to test the connections for leakage after installation. Any leakage that occurs has the potential to alter the conditions of the test being done and might be a violation of EPA regulations.