Refrigeration & Air Conditioning Mechanic Red Seal · Question
When testing a natural gas furnace, a service technician observes a lifting flame and a strong odour of unburnt gas in the combustion chamber during ignition. What is the most immediate diagnostic action required?
A lifting flame and unburnt gas odour indicate an incomplete combustion-related issue, most commonly due to excessively high gas pressure or a critically incorr
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Question: When testing a natural gas furnace, a service technician observes a lifting flame and a strong odour of unburnt gas in the combustion chamber during ignition. What is the most immediate diagnostic action required?
Answer options: ✅ Shut down the furnace immediately and investigate the gas pressure at the manifold.
- Adjust the primary air shutters to lean out the gas-air mixture.
- Check the flame sensor for proper positioning and cleanliness.
- Inspect the heat exchanger for any visible cracks or perforations.
Correct answer: Shut down the furnace immediately and investigate the gas pressure at the manifold.
Explanation: A lifting flame and unburnt gas odour indicate an incomplete combustion-related issue, most commonly due to excessively high gas pressure or a critically incorrect gas-air mixture. Immediate shutdown is necessary for safety.
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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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