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G2 & GAS TECHNICIAN G2 EXAMS (2025 UPDATE)
(BUNDLED TOGETHER WITH COMPLETE SOLUTIONS)
QUESTIONS AND| 100% CORRECT| ANSWERS: ALREADY
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What will be the result if too large a Fire Pot is used in a Converted Furnace or Boiler? - -- <> ---There will be poor efficiency When the installation of an Appliance constitutes a conversion from another form of Energy to Gas, the installer must: - -- <> ---Advise the user in writing of the procedures to be followed to discontinue the Supply of the former form of energy What is the minimum Clearance to Combustibles from the top of the Plenum of a Converted Forced Warm Air Furnace? - -- <> ---1" Inch Gross Stack Temperature is the Flue Gas Temperature: - -- <> --- Upstream of the Draft Hood What is the Minimum Service Clearance in front of a Boiler? - -- <> --- 48" Inches As the Outlet Temperature decreases from a Water Heater to the Heating Loop in a Combination Heating System, the: - -- <> ---Heating Output from the Air Handler Decreases
The discharge piping from the Temperature and Pressure Relief Valve on a Water Heater shall terminate not more than _______ from the floor - -- <> --- 12" Inches Which of the following statements is correct concerning a Combination Heating System employing a Water Heater to supply Domestic Hot Water Heater and Space Heater? - -- <> ---Isolation Valves should be installed in both the Supply and Return Line of the Heating Loop A gurgling sound coming from a firing Water Heater may be a symptom of: - -- <> ---A situation where Deliming is required "Temperature Rise", When applied to a Hot Water Heater is the: - -- **_<<ANSWER
** ---Water Temperature difference across the Heater The Temperature of the Water returning from the Heating Loop in a Combination System employing a Water Heater for Domestic Hot Water Heater and Space Heating must be: - -- **<>** ---Lower than the minimum Temperature required to activate the Burner The components of a Copper Fin Tube, Instantaneous Water Heater are a/an: - -- **<>_** ---Pump, Pump Control, Flow Switch, Temperature and Pressure Relief Valve, and a Limit Control The most likely cause of an Intermittent Hissing Sound "like water dripping on a
something hot" coming from a Water Heater is: - -- <> ---Condensation in the Flue Passage caused by drawing Water from the Tank when the Hot Water has been depleted
Which instrument is used to determine the speed of a Direct Drive Fan Motor? - -- <> ---A Tachometer Which of the following applies if a Furnace is used for temporary Heat in a Residence under construction? - -- <> ---The Furnace must be installed on a finished concrete floor or slab at least 4" thick and 6" larger than the base of the furnace From the following list, What is the most probably cause of a service callwhere a Combustion Gas Odour is detected in the heated space whenever the Circulatiing Blower activities? - -- <> ---Cracked Heat Exchanger The High Temperature Limit Switch in the Circuitry of a Conventional Residential Furnace is wired in series with the: - -- <> ---Gas Valve Which of the following is the best procedure to increase the Furnace Blower Speed? - -- <> ---Close up the Motor Pulley What is the recommended location for a Cooling Coil on a Suspended or Horizontal Furnace? - -- <> ---On the Supply Air Side What is the minimum distance that the Vent from a 75,000 BTUH Category 3 Furnace may terminate from a door? - -- <> ---3' Feet
What is the minimum distance that the Vent from a 175,000 BTUH Category 3 Furnace may terminate from a door? - -- <> ---3' Feet A Low Water Cut Off Device on an automatically fired Hot Water Heating Boiler rated at 350,000 BTUH (102kW) is: - -- <> ---Required when any portion of the Circulating System is located below the Boiler A Low Water Cut Off Device onnan automatically fired Hot Water Heating Boiler rated at 450,000 BTUH is: - -- <> ---Always required A Backflow Prevented used in a Boiler System should be located in the: - -- <> ---Make up Water Line to the system The External Bypass Valve is set by: - -- <> ---Determining the Temperature Rise across the appliance The Relief Valve for a Low Pressure Steam System should be set at: - -- **_<<ANSWER
** ---15 PSIG The Relief Valve for a Low Pressure Hot Water System should be set at: - -- **<>** ---30 PSIG Aquastats respond to changes in: - -- **<>** ---Water Temperature A Fire Tube Boiler has: - -- **<>_** ---Water outside the Tubes and Flue Gases inside
When a Gas Fired Appliance is vented into a chimney flue serving an appliance which burns a solid fuel in a Commercial or Industrial application, How shall the Vent from the Gas Appliance be installed? - -- <> ---Through a separate Flue opening above the Flue Pipe connection from the other appliance A Water Heater with a Draft Diverter is to be connected to a Masonry Chimney using a Single Wall Vent Connector. The Vent Connector rise "R" will be 2 Feet, "H" is determined to be 25 Feet, the Water Heater is rated at 50,000 BTUH and will be located 3 Feet from the Chimney. Determine the Vent Size and maximum input of the Vent if the house is 25 years old. (Do not use interpolation) - -- <> --
- 4" Inch diameter, 67 cfh In a particular Installation, the required Air Supply opening is 50 Square Inches. When using a grill rated at 75% free area, What is the rough opening? - -- <> ---66.6" Square Inches An appliance rated over 400,000 BTUH is installed in a Boiler Room. The combustion Air Opening is calculated to be 90 Square Inches. What size Ventilation Air Opening is required? - -- <> ---10" Square Inches It has been determined that a Free Air Opening of 152" Square Inches is required for an installation. How large would the opening have to be if the grill has 75% Free Area? - -- <> ---203" Square Inches When a Draft Control is required, Which of the following appliances would utilize a Single Acting type Draft Regulator? - -- <> ---An Incinerator
What is the minimum distance above a Flat Roof that a Vent can terminate if it is 8 Feet horizontally from an adjoing building which is 4 Feet higher than the top of the Building on which the Vent is located. - -- <> ---6' Feet The weight of Liquid Propane is compared to the weight of an equal Volume of Water is known as the Specific Gravity of Liquid Propane. What is the Specific Gravity of Liquid Propane? - -- <> ---0. A Blue Flame is the result of mixingbPrimary Air with Gas prior to Ignition. What is this type of Flame referred to as? - -- <> ---A Bunsen Flame A Yellow Flame is the result where there is no Premixing of Primary Air with Gas prior to Ignition. What is this type of Flame called? - -- <> ---A Luminous Flame 5 Boilers with Draft Diverters are to be installed in an enclosed Furnace Room. The volume of the room is 15,000 Cubic Feet. The input for each Boiler is 300, BTUH. What size free air opening is required? - -- <> ---179" Square Inches An Appliance Vent shall terminate from any building Mechanical Air Inlet by at least: - -- <> ---6' Feet What will the result be if the 24 Volt Transformer for a Power Humidifer is wired in Series with the Humidistat and the Humidifier Motor? - -- <> ---The Humidifier Motor will operate properly
What is the normal Supply Air volume for Forced Air Furnace in cfm? - -- <> --- 700 Convection is: - -- <> ---Heat transfer through Fluids Heat Conduction is: - -- <> ---Heat transfer through solid objects Radiant Heat is: - -- <> ---A wave form of heat transfer A British Thermal Unit is the amount of Heat required to: - -- <> ---Raise the temperature of one pound of Water by one degree Fahrenheit If the Fan Compartment door of an appliance is left of the motor: - -- **_<<ANSWER
** ---Current will increase In order to prevent condensation from forming on the outside of a duct, the duct must be: - -- **<>_** ---Insulated on the outside
** ---A Luminous Flame 5 Boilers with Draft Diverters are to be installed in an enclosed Furnace Room. The volume of the room is 15,000 Cubic Feet. The input for each Boiler is 300, BTUH. What size free air opening is required? - -- **<>** ---179" Square Inches An Appliance Vent shall terminate from any building Mechanical Air Inlet by at least: - -- **<>** ---6' Feet What will the result be if the 24 Volt Transformer for a Power Humidifer is wired in Series with the Humidistat and the Humidifier Motor? - -- **<>** ---The Humidifier Motor will operate properly What is the normal Supply Air volume for Forced Air Furnace in cfm? - -- **<>** --- 700 Convection is: - -- **<>** ---Heat transfer through Fluids Heat Conduction is: - -- **<>** ---Heat transfer through solid objects Radiant Heat is: - -- **<>** ---A wave form of heat transfer A British Thermal Unit is the amount of Heat required to: - -- **<>** ---Raise the temperature of one pound of Water by one degree Fahrenheit If the Fan Compartment door of an appliance is left of the motor: - -- **<>** ---Current will increase In order to prevent condensation from forming on the outside of a duct, the duct must be: - -- **<>** ---Insulated on the outside Air filtration devices are generally located in the: - -- **<>** ---Return air plenum A domestic Air Conditioner, What is the minimum Supply Air in CFM per ton of Cooling required? - -- **<>_** --- 400
You are replacing an old Natural Gas Fired Furnace, the old furnace was firing at 140 MBTUH. The heat loss calculations determined that the house, 1200 Square Feet required 45 BTUH per Square Foot. What size Furnace should be installed? - -
- <> ---75 MBTUH You are replacing an old propane fired Warm Air Furnace. The new furnace will be fired at 100 MBTUH, with a blower moving 1400 chm. What size return air duct should be installed on this New Furnace? - -- <> ---12" x 24" From the following, What is is equivalent to 28" W.C? - -- <> ---1 PSIG What is 0.5 psig in "inches W.C."? - -- <> ---14" W.C. If 1 Cubic Foot of Natural Gas is 1000 BTUH, What is the ratio of Combination Air?
- -- <> --- 10 If 1 Cubic Foot of Propane Gas is 2500 BTUH, what is the ratio of Combustion Air?
- -- <> --- 25 If 1 Cubic Foot of Natural Gas is 1000 BTUH, What is the ratio of Dilution Air? - -- <> --- 15 Three Hot Water Boilers, each firing at 500 MBTUH. Two Hot Water Heaters each firing at at 270 MBTUH and a domestic Water Heater firing at 30 MBTUH. Determine the required grill size, assume to have 80% free air space - -- <> ---275" Square Inches
What is the explosion limits for Propane Gas? - -- <> ---2.4 to 9.5% What is the primary component of Natural Gas? - -- <> ---Methane (CH4) When two 10 ohm resistors are connected in Series, what is the net result? - -- <> ---20 ohms When two 10 ohm resistors are connected in Parallel, What is the net result? - -- <> ---5 ohms When two 10 microfarad capacitors are connected in Series, What is the net result? - -- <> ---5 mf When two 10 microfarad capacitors are connected in Parallel, What is the net result? - -- <> ---20 mf State Ohms Law? - -- <> ---Current = Voltage / Resistance What substance is added to Natural Gas to provide an odour to it? - -- **_<<ANSWER
** ---Mercaptan What is the boiling point of Natural Gas (the point at which it changes from a liquid to a gaseous state)? - -- **<>_** ----258 degrees Fahrenheit
The weight of gas compared to the weight of an equal Volume of Air is known as the specific gravity of gas. What is the specific gravity of Natural Gas? - -- <> ---0. The weight of gas compared to the weight of an equal Volume of Air is known as the specific gravity of gas. What is specific gravity of Propane Gas? - -- **_<<ANSWER
** ---1. A 60,000 BTUH Water Heater with no Draft Diverter is to be installed in a closet type enclosure and all air is to be taken from indoors. - -- **<>** ---A 60 Square Inch lower opening only There is a no Heat call for the system, Using the following... Terminals at the Thermostat reads 24 Volts Gas Valve Coil reads 0 Volts Gas Coil to Gas Coil common reads 24 Volts Points across High Limit read 0 Volts Determine which component is open: - -- **<>_** ---Thermostat There is a no Heat call for the system, Using the following... Thermostat terminals read 0 Volts Gas Valve Coils terminals read 0 Volts
Which method of jointed Steel Piping used for Natural Gas Systems is NOT acceptable? - -- <> ---Flared fittings What is the equivalent of a 2" Inch NPS Schedule 40, 90 Degree Threaded Elbow? - -- <> ---5.17 Feet (1.5m) What is the allowable maximum distance Piping supports should be spaced on a 4" Inch Gas Line? - -- <> ---15 Feet (4.5m) What must be done to Piping or Tubing passing through concrete? - -- **_<<ANSWER
** ---It must be sleeved What is the chemical formula of Acetylene? - -- **<>** ---C2H What Temperature is a joint considered to be "Brazed"? - -- **<>** --- 1000 degrees Fahrenheit What is the minimum service clearance vertical of a Boiler? - -- **<>** --- 24" Inches (2 Feet) When installing a 2" NPS piping system in a commercial establishment and branch connections are required for unkniwn additional future appliances. What size must the branch outlet be? - -- **<>** ---2" Inches What size of wire should be used as a Tracer Wire? - -- **<>_** ---16 Guage
Millivolt wiring should be isolated from Line Voltage Wiring because: - -- <> ---The Line Voltage will induce a Voltage into the Millivolt Wiring What shall be provided in the Gas Supply Line to Boiler Room or Confined Area where the total input of the appliance is in excess of 2,000,000 BTUH (585 kW)? - -
- <> ---An Identified Accessible Emergency Manual Shut Off Valve What type of Flux should be used when Brazing Copper Tubing for Propane System? - -- <> ---Non-Corrosive Type What is the minimum Time and Pressure required to test a new welded 4" NPS piping system that is 100 Feet long with supply pressure of 5 PSIG? - -- **_<<ANSWER
** ---24 hours at 50 PSIG or 1.5 times the maximum operating pressure, whichever is greater When is it permissible to use Bushings to reduce piping size? - -- **<>_** ---
Never What must be done if cracks are discovered in the Heat Exchanger of a Furnace? - -- <> ---Replace the Heat Exchanger What is the minimum clearance from the sides of a Domestic Dryer to combustible materials, unless otherwise specified? - -- <> ---6 Inches How is a Pressure Switch tested to see if it is defective? - -- <> ---With the Power Off to the furnace, remove the Electrical leads from the switch.
If a belt on a Blower is too tight, What will happen to the Blower Motor Current? - -- <> ---Increase The maximum pressure loss between the termination of the utility installation and an appliance for piping system with supply pressure in excess of 14" W.C. shall not exceed - -- <> ---1.0" W.C. (0.250 kPa) How often should Oxygen Regulators be oiled? - -- <> ---Never In applications with frequent operation of throttling of Water Flow you would use:
- -- <> ---A Globe Valve What is the minimum closed Thermocouple reading? - -- <> ---10 mV What does a Pictorial Diagram show? - -- <> ---The components location If resistance of a Wire increases: - -- <> ---Temperature increases Final drawings on a Job are called: - -- <> ---As Built Drawings A Thermocouple produce a maximum of: - -- <> ---1 Volt The oncoming Power Supply to residential homes is: - -- <> ---240/1/
The working pressure differential between the gas meter outlet and the appliance regulator inlet at furthest appliance from meter - Define pressure drop 0.5" w.c. - What is the Max pressure drop >7" w.c. NG 1" w.c. - What is the Max pressure drop 7" - 14" w.c. NG After piping system is installed and before any appliance is connected to it. - When do you do a high pressure test?
- Isolate the piping system -
- Cap or plug open ends -
- Insert a pressure gauge at one end of the system -
- Pressurize system with air or inert gas to specified test pressure. - How do you do a High pressure test
- High pressure test prior to connecting appliance. Disconnect piping at gas meter and before appliance valve train. -
- Leak test with meter and appliance connected under normal operating pressure. Use a manometer or lowest volume test dial on meter. 10 min duration -
