Refrigeration & Air Conditioning Mechanic Red Seal · Question
A new refrigeration system containing R-407C is being commissioned. The manufacturer specifies a subcooling of 8 K (8 °C) at the liquid line outlet. If the liquid line temperature is measured at 25 °C and the condensing pressure corresponds to a saturation temperature of 35 °C, what adjustment should the technician make?
The current subcooling is 35 °C (saturation) - 25 °C (liquid line) = 10 °C. The manufacturer requires 8 °C. Since the current subcooling (10 °C) is higher than
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Question: A new refrigeration system containing R-407C is being commissioned. The manufacturer specifies a subcooling of 8 K (8 °C) at the liquid line outlet. If the liquid line temperature is measured at 25 °C and the condensing pressure corresponds to a saturation temperature of 35 °C, what adjustment should the technician make?
Answer options: ✅ Add more refrigerant to increase subcooling.
- Remove refrigerant to decrease subcooling.
- Adjust the TXV superheat for evaporator performance.
- Check for non-condensables as the subcooling is too high.
Correct answer: Add more refrigerant to increase subcooling.
Explanation: The current subcooling is 35 °C (saturation) - 25 °C (liquid line) = 10 °C. The manufacturer requires 8 °C. Since the current subcooling (10 °C) is higher than specified (8 °C), this indicates an overcharge. Therefore, refrigerant should be removed to decrease the subcooling, bringing it within specification.
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- Which of the following refrigerants is a hydrofluorocarbon (HFC) and has a high ozone depletion potential (ODP
- Which component is responsible for compressing the refrigerant vapour to a high pressure and temperature?
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- What is the main operating characteristic difference between a fixed orifice (capillary tube) and a Thermostat
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