Hvac Study guides, Class notes & Summaries

The International Mechanical Code considers a "flammable Vapor" to be concentration of flammable constituents in the air which exceeds _____________ percent of its flammability limit. : 25% During installation or service of electrical controls, a digital multimeter set to voltage must be connected in what manner? : In parallell Unvented fuel-burning room heaters are NOT permitted in a Group ___________ occupancy? : A According to the Code, smoke detectors shall be installed in re...

Heat which causes a change in temperature of a substance is called; : Sensible Heat. heat added to substance without a rise in temperature; (example: liquid refrigerant to gas) this process is called? : Latent heat of vaporization. Heat added to the refrigerant in a vapor state after the evaporation process is called; : Superheat. A scroll compressor move refrigerant by means of; : Involute Spirals. The movement of heat by way of fluid (or air) is called; : Convection. The movement o...

HVAC NATE Gas Heat Exam Prep (Latest 2024/ 2025 Update) 100% Correct Questions and Verified Answers| Grade A Q: When starting up a dual system, the temperature rise method for determining airflow cannot be used with compressor cycle of the heat pump because: Answer: The capacity of the system varies too much with outdoor temperature. Q: The flame pattern a technician would expect to see on a properly operating single stage gas furnace equipped with "in shot" type burner is a:...

HVAC NATE Heat Pump Exam (Latest 2024/ 2025 Update) 100% Correct Questions and Verified Answers| Grade A Q: What is the absolute pressure at sea level if a gauge pressure is 35 psig? Answer: 49.7psia Q: 100,000 BTUH output furnace. Return air temp is 65F. Supply air is 135F. What is the CFM? Answer: 1323CFM Q: What is the best method of repair when a residential supply diffuser is noisy because of a loose vane? Answer: Replace the diffuser. Q: When...

HVAC Gas Heat Certification Exam Prep (Latest 2024/ 2025 Update) 100% Correct Questions and Verified Answers| Grade A Q: Why is excess air supplied to all gas-burning appliance burners? Answer: to ensure that there is enough air all all times. Q: The purpose of a gas regulator at a gas burning appliance is to? Answer: B. decreases the pressure to the burner Q: Ture or False: All gas valves snap open and closed. Answer: False Q: Which of the followin...

HVAC Gas Heat Exam (Latest 2024/ 2025 Update) 100% Correct Questions and Verified Answers| Grade A Q: Why is specific gravity of a gas important? Answer: It affects the gas flow through the piping and through the orifice of the furnace. Q: What is an orifice and a spud? Answer: An orifice is a precisely sized hole in a gas fitting which gas flows from the manifold to the burners. A spud is another name for a gas fitting. Q: If both a light gas and a heavy gas are at...

HVAC Gas Heat Certification Exam (Latest 2024/ 2025 Update) 100% Correct Questions and Verified Answers| Grade A Q: What is the volume of flue gas produced from a 60,000 BTU/h Category I fan assisted Natural Gas furnace operating with 50% excess air? Answer: 600 cu ft. Q: The purpose of a flue baffle is to Answer: Increase heat exchange Q: The LP gas pressure supplied to the appliance gas valve should be Answer: 11 - 13 in. W.C. Q: An installed gas furna...

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