Refrigeration & Air Conditioning Mechanic Red Seal · Question
A technician observes that the control voltage transformer in an HVAC unit has blown its primary fuse repeatedly. All 24 V AC loads appear normal. What is the MOST likely cause of this recurring fuse failure?
If all 24 V loads appear normal and the primary fuse repeatedly blows, it strongly suggests that the combined current draw of all the connected control loads ex
Start free practice for Refrigeration & Air Conditioning Mechanic Red Seal
500 questions · no signup required · 40 free questions per day
Question: A technician observes that the control voltage transformer in an HVAC unit has blown its primary fuse repeatedly. All 24 V AC loads appear normal. What is the MOST likely cause of this recurring fuse failure?
Answer options:
- A short circuit in the secondary (24 V) control circuit.
- An intermittent open circuit in the primary winding of the transformer. ✅ An undersized control transformer for the connected load.
- A high impedance short in one of the low voltage wires.
Correct answer: An undersized control transformer for the connected load.
Explanation: If all 24 V loads appear normal and the primary fuse repeatedly blows, it strongly suggests that the combined current draw of all the connected control loads exceeds the rated capacity of the control transformer. This causes the transformer to overheat and the primary fuse to blow, indicating it's undersized.
Start free practice for Refrigeration & Air Conditioning Mechanic Red Seal
500 questions · no signup required · 40 free questions per day
More about Refrigeration & Air Conditioning Mechanic Red Seal
Related Questions
- 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
- Which type of electric motor requires a capacitor for starting and running, offering higher efficiency and bet
- When evacuating a refrigeration system, what is the recommended deep vacuum level, typically measured in micro
More for Refrigeration & Air Conditioning Mechanic Red Seal candidates
FAQs
Question explanations
- 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
Ready to practice?
Free, no signup required. Build a wrong-question list as you go.
Start Free Refrigeration & Air Conditioning Mechanic Red Seal Practice →Related courses
Other Canadian certifications candidates often prepare for alongside this one.