Commercial Food Equipment Service Association (CFESA) Gas Practice Test

These questions are part of the practice quiz. Start practicing

• Does the bypass flame on an FD thermostat go out if the flame is properly adjusted?
• What is the consequence of having less temperature difference between the hot and cold junction?
• When is lockout supposed to occur in an ignition system?
• What condition can cause a downdraft to occur?
• What might be a common cause of misdiagnosing mercury flame switch failures?
• What causes LP gas to accumulate in a space?
• What is the minimum incoming gas pressure required for natural gas to prevent problems?
• What can be done to minimize extinction pop?
• What is a common problem experienced when using a domestic connector in a commercial installation?
• What should you do if the pilot flame is poor quality during troubleshooting?
• What is a significant downside of using a hot surface igniter as a flame sensor?
• What type of pad should be used to clean an igniter or flame sensor to avoid damage?
• What are the two primary reasons that BJ thermostats start to leak gas around the knob?
• Where does the flame burn on a ceramic tile infrared burner?
• Under what conditions is a multiple try ignition system allowed before a permanent lockout occurs?
• What is the typical range for the heating value of natural gas?
• What is the method for checking flame sensor current when the igniter also serves as the sensor?
• Why are manufacturers increasingly using inshot burners?
• Is natural gas heavier or lighter than air?
• What type of pipe is typically required for natural gas lines?
• What happens if the calibration of the bypass flame is off from the knob on a FD thermostat?
• What is the main function of a gas thermostat in a bleed-type combination gas valve?
• What is the primary function of a flue in gas appliances?
• What is the correct flame current value for a Johnson Controls G700 series ignition module?
• What is the purpose of the stainless steel braid on a commercial flexible gas connector?
• How do you check the flame sensor current when a separate flame sensor is used?
• Which characteristic of flame is crucial for thermocouples?
• If the pilot light goes out when the burners attempt to ignite, what might be wrong with the pressure regulator?
• What happens when there is an insufficient flow of secondary air?
• What is one reason incomplete combustion can result in harmful byproducts?
• Why is it crucial to monitor gas pressure accurately?
• What maintenance task is critical for ensuring the reliability of hot surface igniters?
• What type of lubricant is recommended for use on tapered plug gas valves?
• What condition should be avoided to prevent explosions in gas systems?
• For a complaint that the pilot will not stay lit, which step should you take first on an electric safety valve?
• How do dirty connections impact thermocouples?
• Which procedure should be followed to adjust the primary air on a burner?
• What is typically the first step in troubleshooting a burner issue?
• What is the function of a pressure regulator vent?
• If all checks are okay in a troubleshooting scenario, what should you do next?
• What is the first step to correct a loose thermostat shaft problem on a FD series thermostat?
• How do you properly test the no-load output of a thermocouple?
• What is the hottest part of a flame?
• Complete combustion of fuel primarily produces which of the following?
• What is an FDH or FDTH thermostat used for?
• What characteristic of double wall vent pipe helps prevent fire hazards?
• How can you determine if a gas valve is in the 'on' or 'off' position?
• When checking microamps in a troubleshooting scenario, what should you check if the microamp reading is low?
• Why do steel burners corrode prematurely?
• What is the original material used in hot surface igniters?
• What is primarily responsible for a shapeless flame flowing totally off the burner?
• How is LP gas stored in tanks?
• When should the ignition module stop sparking?
• What is one major downside of the original hot surface igniters?
• What part is responsible if the main burner stays on when the pilot goes out?
• Which safety measure is crucial when handling LP gas?
• When can you expect an FD thermostat's bypass flame to extinguish?
• Before reassembling a burner valve, what should be inspected?
• What characteristic of LP gas contributes to its higher volatility compared to natural gas?
• What is the recommended installation guideline regarding the vent pipe connectors?
• What is one of the main factors in determining the size of gas piping according to gas code?
• How can a downdraft create problems for gas equipment?
• What will happen if a bypass flame is set too high?
• What method is commonly used to check for gas leaks?
• Which component on a gas valve can be adversely affected by improper lubrication?
• What does the term "lockout" refer to in gas ignition systems?
• What voltage range indicates a healthy safety valve using a thermocouple?
• What is the appropriate length for a thermocouple lead?
• Which type of manometer is considered the most accurate?
• What is a combination gas valve used for?
• What type of sealants should be used on natural gas fittings?
• In what state is LP gas typically stored due to its properties?
• How should the sensor on a hydraulic safety valve be mounted in the pilot burner?
• What type of wire is required from the ignition module to the igniter?
• If carbon monoxide is being produced, will there be aldehydes?
• What color should the surface of an infrared burner typically be?
• During flame rectification, in which direction is the current greater?
• If horizontal ducts are used to bring in fresh air, how much space is needed per 2000 Btus?
• What might indicate incomplete combustion in a burner?
• What is the heating value for LP gas?
• What will result if a burner manifold is not exactly perpendicular to the burner?
• What is critical when drilling an orifice?
• Which of the following statements is true regarding convection ovens?
• How hot must the sensor get on a hydraulic safety valve for it to function correctly?
• What mechanism does a hydraulic safety valve use to operate?
• How can you determine if a gas problem is related to pressure or volume?
• Which type of orifice is larger for 1000 Btu: natural gas or LP gas?
• If the main burner does not achieve a full flame when using a hydraulic safety valve, what should be your first action?
• How will the burner flame appear if the orifice is not properly aligned?
• How many byproducts remain after burning one cubic foot of natural or LP gas?
• Which of the following conditions is NOT good for burner operation?
• Which gas is more volatile due to its higher Btu rating and density?
• What is the purpose of adjusting the pressure regulator head?
• Which factor does NOT typically affect the life expectancy of a hot surface igniter?
• How is a BJ thermostat mounted to the equipment?
• What is the key difference between yellow jacketed and black jacketed CSST tubing?
• Which size orifice is required for a natural gas system with a demand of 40000 Btu at 4.0 in/wc?
• What steps should be taken to repair a tight tapered plug gas valve?
• Why is maintaining proper air ratios crucial in a combustion system?
• What are the two basic types of disconnects?
• Which of the following can indicate that the gas pressure is too low?
• What occurs in an LP tank when gas is drawn off?
• In what scenarios might local jurisdictions allow exceptions to using black iron pipe?
• What is a potential issue if the inlet and outlet pipes of a gas valve are mismatched in size?
• When inspecting a tapered plug valve, what should you look for on the plug surface?
• Can infrared burners be repaired or rebuilt?
• A confined space connected to an unconfined space requires how much combustion air opening per 1000 Btus?
• In addition to removing combustion byproducts, what is another function of the flue?
• What is the equivalent length of a three-quarter tee if the direction of flow changes?
• Can the tapered plugs in tapered plug gas valves be interchanged?
• What common issue can cause intermittent operation of hot surface ignition systems?
• Why is gas pressure crucial for impingement target burners?
• What material can be used for LP gas lines?
• What factors determine the gas flow rate through an orifice?
• How is a GS thermostat used in conjunction with equipment operating at 150000 Btu?
• What is one purpose of the ground bonding codes for CSST?
• What precaution should be taken when installing a new thermocouple?
• Why is double wall vent pipe necessary in venting systems?
• What can happen if the hot surface igniter is shorted?
• Do all combination gas valves regulate the pilot gas pressure?
• Which component must be flattened while correcting a loose thermostat shaft on a FD series thermostat?
• Is it advisable to replace a failed part of a combination gas valve?
• What is the primary function of a draft hood in gas equipment?
• What effect does increasing the spring tension on a pressure regulator diaphragm have?
• On what type of applications do you find FDTO thermostats?
• What is the major difference between a commercial and domestic flexible gas connector?
• The DC voltage generated by a thermocouple or thermopile is directly related to what factor?
• Why is it critical to check the data plate for natural gas equipment?
• What is required to convert a combination gas valve from natural gas to LP gas?
• What is a full port ball valve designed to do?
• Where is the bypass adjustment located on a BJ thermostat?
• Which of the following is a dangerous byproduct of incomplete combustion?
• In a direct ignition system, what does the igniter actually light?
• What causes an almost totally yellow flame in a gas appliance?
• Why are dual gas valves necessary with spark ignition systems?
• How tightly should a regulator be attached to the pipe fittings?
• How is primary air controlled?
• What should be the position of the manual shut-off valve relative to the equipment?
• Why is the size of the flue considered critical in gas equipment?
• What is the minimum area required for a fresh air opening in a gas appliance?
• What is the function of a Bunsen burner?
• When troubleshooting a hydraulic safety valve, what should you confirm about the sensor tip if the pilot lights but the main burner does not ignite?
• What is running pressure?
• How should a thermocouple be stored before installation?
• What are the primary functions of a bypass flame?
• How much of a thermopile must be covered by the pilot flame for optimal performance?
• Why are low NOX burners becoming increasingly popular?
• What overall effect do cracks in the hot surface igniter material have?
• What is the function of a burner orifice in gas equipment?
• What is the primary composition of natural gas?
• What is typically the first valve section on a redundant gas valve?
• Commercial flexible gas lines must have what approvals to be acceptable in most code areas?
• When operating, what color do Low NOX burners typically show?
• What is the function of a hot surface igniter in a gas ignition system?
• What can happen if an orifice is drilled off center?
• What is a common maintenance task to ensure igniters work effectively?
• What is the normal flame current when using a hot surface ignition system?
• What can a malfunctioning flame sensor lead to?
• What is the minimum sized combustion air opening for a confined space connected to an unconfined space?
• If all connections are good and components are clean, what is often the cause of low flame sensor current?
• In a confined space, where must combustion air openings be located?
• What is essential to check for differing voltages in hot surface ignition systems?
• What can happen if a regulator is over tightened?
• What symptom might indicate a problem with the pressure regulator?
• Why is running pressure important?
• What material is primarily used in most modern hot surface igniters?
• Can electric safety valves fail in a partially open position?
• What should you do after adjusting the shaft plate on a FD thermostat?
• Why is it important to note the pipe size of both sides of a combination gas valve?
• Which of the following gases are classified as LP gas?
• What is a common maintenance task for pressure regulators?
• How many different voltages are required for a hot surface ignition module using a 120V hot surface igniter?
• What is the typical no-load output voltage range of a thermocouple?
• What might indicate a gas regulator is defective?
• What is the ideal flame color for optimal burner performance?
• What is the main risk of having undersized gas lines?
• What is the output voltage of a thermopile under no-load conditions?
• What is the best method for checking a hot surface igniter?
• What happens if a thermopile is not adequately covered by the pilot flame?
• Why is clean combustion air needed for infrared burners?
• What is the method for calibrating a GS thermostat?
• What indicates that a burner has a secondary air problem?
• What characteristic of silicon oxide affects the functionality of hot surface igniters?
• How can proper air shutter adjustment affect burner performance?
• What is the normal operating pressure for LP gas equipment?
• What is a potential consequence of having an off-center drilled orifice?
• Where should the flame sensor be positioned within the flame?
• What causes flames with yellow tips?
• What is the most common cause of thermocouple failures?
• What causes flames to lift off of a burner and maintain their shape?
• What is the primary function of a thermopile?
• What is the proper flame current range for a Honeywell spark ignition module?
• Why is it crucial to understand the flame current for hot surface igniters?
• Why is it important to ensure proper grounding for CSST?
• What is a downdraft in the context of gas venting?
• Combustion air openings should be situated at what measurements from both the floor and the ceiling?
• What controls the secondary air to a burner?
• Describe the proper flame for an aerated pilot burner.
• What is meant by the term "port loading" in relation to burners?
• What is the primary function of a manometer?
• What type of air do infrared burners require for optimal operation?
• What are the byproducts of complete combustion?
• What are aldehydes?
• Under what circumstances should a draft hood be utilized?
• What typically causes the seals between the tiles of infrared burners to decay?
• How should one properly troubleshoot a combination gas valve?
• In what units is gas pressure typically measured?
• How much of the thermocouple tip should be covered by the pilot flame?
• What should be checked to determine natural gas operating pressure?
• When is a flexible gas connector allowed for an equipment installation?
• Is a bleed type combination gas valve known for being fast or slow operating?
• What must be designed and installed with a power vent hood?
• What are the three essential components required for combustion?
• How does the ignition module differentiate between a flame and a sensor shorted to ground?
• What controls the primary air to a burner?
• What component senses the flame to prove ignition?
• How can you identify the proper installation direction for a gas regulator?
• What type of burner typically operates at higher temperatures to reduce emissions?
• What is the maximum amp draw for a 120v hot surface igniter?
• What are the three major functions of the spark ignition module?
• Which gas valve type is known for less likelihood of seizing up over time?
• What components does a combination gas valve typically integrate?
• Can a vent pipe be directly connected to the flue on gas equipment?
• What type of gas is typically used for heating and cooking in homes?
• How do you adjust the bypass flame on a FD series thermostat?
• What is the function of a spoiler screw in a burner?
• What is the main purpose of a restraining cable in gas equipment installation?
• What typically causes whistling at the burner orifice?
• On which side of the flexible gas connector is the female section of the quick disconnect installed?
• What is a key step in calibrating a FD thermostat?
• What is the maximum allowable dropout voltage for an electric safety valve using a thermopile?
• What is the purpose of measuring static pressure?
• What happens if a thermocouple is kinking during installation?
• Can hydraulic safety valves fail partially open?
• What effect can high incoming gas pressure have on pilot burners?
• To convert orifices from LP to natural gas, what is the recommended action?
• What differs between a vent and a flue?
• What size orifice is needed for a natural gas appliance operating at 30000 Btu with a pressure of 3.5 in/wc?
• What is the typical resistance range for a normal hot surface igniter?
• What are potential ways a new thermocouple can be damaged during installation?
• Is the regulator vent located on the inlet side or outlet side of the regulator?
• What characteristic identifies a properly functioning combustion flame?
• What size vent pipe is needed for equipment rated at 160,000 Btu located 10 ft from the roof opening?
• For LP gas operating at 40000 Btu and 11 in/wc, what is the required orifice size?
• How does an electronic safety valve function?
• If a hot surface ignition module is inoperable, what other part should you also consider changing?
• What is one way to check the cleanliness of the igniter and flame sensors?
• What does a proper make up air system prevent?
• Why are infrared burners favored for use in broilers?
• What is a common source of LP gas?
• What is the exact procedure for recalibrating a BJ thermostat?
• What determines how much carbon dioxide your blood absorbs?
• What type of equipment commonly uses GS thermostats?
• When should a 24v hot surface igniter be replaced?
• In troubleshooting an oven with an electronic spark ignition system that sometimes does not heat, what is the first step?
• What should be done with the tapered plug if there are deep scratches found during inspection?
• If a pilot goes out when the main burner comes on, where is the problem most likely found?
• Where must the manual gas shut off be installed?
• What defines a redundant gas valve?
• In what type of cooking equipment are bleed type combination gas valves commonly utilized?
• Hot surface igniters are manufactured in which of the following voltages?
• What is primary air?
• How tight should the nut on the end of the thermocouple be when secured?
• How is outside combustion air typically opened for ventilation?
• What should be regularly maintained to ensure accuracy in gas pressure measurement?
• What must be avoided when mounting the sensor of a hydraulic safety valve?
• What detail on the equipment data plate is infrared burners particularly sensitive to?
• What is secondary air?
• What should be the first consideration when selecting a pressure regulator?
• How does LP gas compare to air in terms of weight?
• What is the second gas valve section referred to on a dual gas valve?
• What is one characteristic of LP gas regarding its volatility?
• What is one sign that indicates the safety valve may be faulty?
• What is the result of a poorly adjusted bypass flame in a gas appliance?
• What electrical codes must be followed when using CSST tubing?
• What is the major cause of BJ thermostat failure?
• How does higher altitude affect the function of an orifice?
• What is a common cause of flashback in a burner?
• How does a thermocouple generate an electrical current?
• Can pilot burners wear out, and how can you tell?
• Where does natural gas primarily come from?
• What is the primary cause of most infrared burner failures?
• When the main burner ignites, what can cause the pilot to go out?
• What does the gas code specify regarding gas piping size?
• What might happen if the regulator vent becomes blocked with dirt?
• How does a water manometer function?
• Which component directly influences the working gas pressure in a combination gas valve?
• What is the maximum allowable dropout voltage for an electric safety valve using a thermocouple?
• What problems can arise from a dirty vent on a combination gas valve?
• What does a blue flame indicate on an infrared burner?
• On what type of applications do you find FDO thermostats?
• Robertshaw FD thermostats are usually found in what type of equipment?
• Which gas measurement tool is used for checking pressure differentials?
• If there are aldehydes, is there carbon monoxide present?
• What does the gas code specify regarding the vent of an installed regulator?
• What is the procedure for adjusting a bypass flame on a BJ thermostat?
• What should the pilot flame look like if functioning correctly?
• What is a clear indication of the need to check gas pressure?
• What important factor needs to be considered for vent pipe sizing?
• When checking gas pressure, should the burners be in an on or off position?
• What is the approximate heating value of a cubic foot of natural gas?
• What indicates that a burner needs a primary air adjustment?
• A three-quarter elbow is equivalent to how long a pipe?
• What property of igniters is typically a concern when handling or cleaning them?
• What are the two key functions of primary air in an infrared burner?
• Why is LP gas considered more dangerous to work with than natural gas?
• What does a gas pressure reading of 4 inches wc indicate on a U-Tube manometer?
• Why is it important to check the adjustment of the bypass flame?
• When mounting a BJ thermostat to a flange, what must you be careful of?
• What is necessary to create a low NOX burner?
• What aspect allows silicon nitride igniters to outperform older models?
• How does the mercury flame switch operate to close contacts?
• What should the normal millivolt reading be under load for a safety valve using a thermocouple?
• Which statement is true regarding the operation of a safety valve?
• How much air is required to burn one cubic foot of natural gas?
• When should you consider replacing a BJ or FD thermostat?
• Does natural gas have any odor when it comes from the ground?
• When connecting a hot surface ignition module, what must be ensured regarding the incoming power supply connections?
• What happens as you increase the flame size on a non-aerated pilot burner?
• What type of valve operates using a gas thermostat instead of a rocker arm?
• For a combustion air opening directly to the outside or through a vertical duct, how much space is required per 4000 Btus?
• What must be done to orifices when converting from natural gas to LP gas?
• Which of the following is a potential issue if incoming gas pressure is too low?
• What does a clogged vent fitting in a pressure regulator typically cause?
• What is a common symptom of BJ thermostat failure?
• What is an advantage of the new material used for hot surface igniters?
• What type of vent pipe is recommended for commercial applications?
• What does a throttling thermostat refer to?
• What is a potential issue if the dropout voltage on the safety valve is high?
• What type of flame is necessary for a thermocouple to function correctly?
• What is the function of air shutters in a burner system?
• Why is it necessary to hold down the button on the safety valve after the pilot burner lights?
• What protective feature is incorporated into the construction of approved disconnects?
• What must all outside combustion air openings be protected with?
• What is one advantage of using ball valves over tapered plug valves?
• What component is likely at fault if pilot gas continues to flow after the pilot has been out for a few minutes?
• What kind of vents do most commercial kitchens have?
• What condition can cause extinction pop in a burner?
• What type of components are replaced if the igniter is consistently operating at high amperage?
• What does "specific gravity" refer to in terms of gas?
• For two ovens, each rated at 80,000 Btus, what size vent pipes are required if the roof height is 10 feet?
• What is a common indicator of inadequate primary air supply?
• What does the diaphragm in a combination gas valve do?
• How does the pressure regulator section of a combination gas valve function?
• What is the first step in lighting a pilot operated by a safety valve?
• What is the first step in troubleshooting a pilot burner that will not light on a system with a pilot safety valve?
• Before checking the calibration on any gas thermostat, what should you check?
• What information is necessary to obtain a replacement combination gas valve?
• What is a major concern when using a gas meter to measure gas flow?
• Why are one-time lockout modules particularly needed?
• What issue can occur when oven doors do not shut tightly?
• Are ball valves generally repairable?
• Why is a manual gas shut off required at the equipment?
• If the burner lights but the igniter continues to spark, what part is likely faulty?
• Which term best describes the operational capability of a properly functioning BJ or FD thermostat?
• Why is carbon monoxide considered particularly dangerous?
• What effect does a hot ambient environment have on a thermocouple?
• What action should be taken if the pilot lights but the main burner does not come on in a system with an electric safety valve?
• What is a bypass flame?
• What does the solenoid coil portion of a combination gas valve control?
• What does the hot junction of a thermocouple refer to?
• What can happen if a downdraft disrupts the combustion chamber?
• Why are many gas lines found to be undersized?
• What does static pressure measure in gas systems?
• What is a significant advantage of using infrared burners?
• What is the purpose of gas pressure regulation in appliances?
• How can you reset an ignition module that is in a locked out state?