Refrigeration & Air Conditioning Mechanic Red Seal · Question
A technician observes excessive subcooling at the outlet of a condenser in a direct expansion (DX) system, coupled with a higher-than-normal head pressure. What is the probable cause?
Non-condensable gases accumulate in the condenser, reducing the effective heat transfer surface. This causes an increase in condensing pressure and a proportion
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Question: A technician observes excessive subcooling at the outlet of a condenser in a direct expansion (DX) system, coupled with a higher-than-normal head pressure. What is the probable cause?
Answer options:
- Undercharge of refrigerant ✅ Non-condensables in the system
- Low ambient temperature
- Evaporator fan motor failure
Correct answer: Non-condensables in the system
Explanation: Non-condensable gases accumulate in the condenser, reducing the effective heat transfer surface. This causes an increase in condensing pressure and a proportionally higher subcooling as the refrigerant is forced to condense in a smaller area.
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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?
- According to the Canadian Electrical Code (CEC), what is the minimum required working clearance in front of el
- What is the main operating characteristic difference between a fixed orifice (capillary tube) and a Thermostat
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