Charging liquid HCFC-123 into a system under a deep vacuum could cause what to happen unless necessary precautions are taken?

Correct Answer: Option C — system secondary refrigerant to freeze

Charging liquid HCFC-123 into a deep vacuum causes rapid flash evaporation, drastically dropping the local saturation temperature. In chillers utilizing water as a secondary refrigerant, this extreme cooling causes the water to freeze and rupture tubes.