Which statement about Type I charging methods is true?

• A. The only allowed method is by volume
• B. When allowed by the manufacturer, charge by weight using a scale (weigh-in)
• C. Charge by pressure alone
• D. Charge by visual estimation

Answer: (B)

Charging by weight using a scale, when allowed by the manufacturer, is the most accurate way to add refrigerant to a Type I appliance. Mass is the direct measure of how much refrigerant is in the system, so weighing in avoids the guesswork that comes with other methods. Refrigerant density changes with temperature, and system conditions vary, so volume or pressure alone can mislead you about the actual amount charged. Visual estimation is even more unreliable because it depends on appearance rather than a precise quantity. The manufacturer’s data usually specify the exact charge in ounces or grams, and you can achieve that exact amount by weighing the added refrigerant. If weigh-in isn’t permitted for a given unit, you should follow the manufacturer’s recommended method.