NATE GAS HEAT PRACTICE GUIDE QUESTIONS WITH CORRECT ANSWERS GRADED TO PASS

What precautions are required when mounting any gas furnace on a wood platform in an attic? - None The gas control valve may be damaged if exposed to an inlet pressure above what? - 14 inch W.C. How many elbows and joints should a vent connector have? - As few as possible to reduce resistance of flue gases. Under what conditions, if any may the technician route the exhaust of the furnace into the exhaust vent of the water heater: - Under no conditions may you use the water heater exhaust vent. How may a technician terminate the intake and exhaust for proper operation of a high efficiency gas furnace when using scheduled 40 PVC pipe: - By using the specific manufacturers termination kit or make one to meet their requirements. When suspended with metal strap and no saddle, flexible duct should be: - supported with a minimum strap width of 1/2". A technician is installing a gas furnace and the customer has decided not to install an air conditioner. Making this decision, the affect it will have on the installation of the supply ductwork is: - Leave adequate space should be allowed for addition of a coil in the future when feasible. Leveling of a Mercury bulb is __________ - Critical Spray-type atomizing humidifiers are installed to do what? - Discharge moisture into the supply duct. Electronic air cleaners (EAC) installed in a gas furnace system should be wired so they: - Only operate any time the EAC On-Off switch is turned to ON. The LP gas manifold pressure is commonly what? - 10 to 11 in. W.C. The polarity of a 120V gas furnace equipped with electronic flame rectification is important because: - The ignition control may not prove flame. Using a voltmeter, a technician can determine voltage drop at a gas furnace: - With the furnace not operating and then with the furnace operating. The setting on a 4 speed PSC blower motor can be changed by changing the: - Motor tap connection. When starting up a dual system, the temperature rise method for determining airflow cannot be used with compressor cycle of the heat pump because: - The capacity of the system varies too much with outdoor temperature. 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: - Hard and forceful flame with a light blue appearance and little or no yellow. What is recommended method for a pressurization leak test of a fuel gas pipe? - Compressed air What is a diaphragm type differential pressure gauge used for? - Measure air pressure. The pressure reading on a manometer is expressed in: - Inches of water. A technician measures the return air temperature of a 100,000 BTU output gas furnace to be 65°F and the supply side air temperature is 135°F. Calculate the CFM. - The CFM would be 1323. A dirty or clogged air filter in an operating gas furnace can cause what? - Increase temperature rise. What can bent vanes on a direct drive blower wheel in a gas furnace cause? - Loss in airflow, excessive blower motor wear, and increase noise.