NATE Gas Furnace Service 117 Questions with Correct Answers 100% Verified What is the typical load rating of the branch circuit over-current protection for a residential gas furnace?
- Correct Answer 25 Amp
What is recommended for a pressurization leak test of fuel gas pipe? - Correct Answer Compressed air When selecting a replacement indoor blower motor, Which criteria should be included? - Correct Answer Motor horsepower Induced draft blowers in direct vent condensing furnaces pull combustion air from: - Correct Answer Outdoors only What is the primary purpose of an off delay timer in a gas furnace? - Correct Answer Remove residual heat and prevent nuisance limit trips Combustion air is often brought into a non-direct vent gas furnace, located in an interior closet (confined space). What consideration is important to remember? - Correct Answer Two permanent openings of sufficient size must be used To minimize noise problems in residential duct systems, What is the range (recommended to maximum) of design air velocity in the rectangular main supply trunk? - Correct Answer 700 to 900 feet per minute The height limitation for a vertical combustion air intake on a condensing gas furnace is set by: - Correct Answer The furnace manufacturer When working on burners in a gas furnace: - Correct Answer The individual burners must be mounted in correct alignment A line voltage fuse is sized to: - Correct Answer Protect the conductors 1 / 2
A thermopile system usually generates its own control circuit voltage of: - Correct Answer 750 mV With a non-direct vented furnace located in a basement, what are the requirements for the space to qualify as an "unconfined space"? - Correct Answer At least 50 ft3 of air volume for every 1000 Btu/h capacity of all combustion appliances in the space There are two generally used methods for controlling temperature and humidity within individual zones of a residence. One is to use dampers to control supply airflow to each zone. What is the other method?
- Correct Answer Use separate and independent systems to condition the air in each zone
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When troubleshooting a blower motor circuit on a packaged system, 244V is measured across the motor and no amperage is measured. What is a likely problem with this system? - Correct Answer An internal overload device is open The complaint is that there is static electricity throughout the house. The home has a bypass humidifier.The technician has checked the humidistat and verified that it is set properly. What would the technician check next? - Correct Answer Check that humidifier damper is open The outdoor winter temperature for which a gas furnace is to be sized is called the outdoor design temperature. The tables for winter outdoor design temperatures are measured in: - Correct Answer Dry bulb temperature only If too much primary air is used on a ribbon burner, the flame will: - Correct Answer Lift off the burner What is a likely problem if a gas furnace has a temperature differential across the heat exchanger which exceeds the value on the manufacturer's rating plate? - Correct Answer Inadequate system airflow What is an industry accepted method for locating a suspected natural gas leak? - Correct Answer A soap solution A typical four-way multipositional gas furnace is converted from upflow to downflow by: - Correct Answer Turning the furnace upside down with specified alterations