G2 Gas Technician Module 17 Revised (2023/2024) 100% Pass

G2 Gas Technician Module 17 Revised (2023/2024) 100% Pass What are the factors governing a conversion? Availability of gas, efficiency if converted, access to combustible air, satisfactory ductwork, can a chimney liner be installed, clearances from combustibles, manufactures recommendations, if a water heater is also being installed (common vent or power vent), and age of the appliance Oil fired furnaces are recommended not to be converted at a certain age what is age is this? 10 years clause 4.3.5 What are the responsibilities of the installer when converting? Determine that it can accept gas and will operate satisfactory for a reasonable length of time. What must be done when converting a boiler? 1. Check for revirtible flue; center line must be at leas 12" above burner port 2. Visually inspect for leaks 3. Open drain at bottom and flush until water is clear 4. Sediment can hide a leak at the bottom Where must a pressure relief drop tube be located on a boiler? The pressure relief tube must be withing 12" of the floor What must be done if a warm air furnace does not have a revertible flue? Center line of the flue collar is 12" above burner port and barometric draft regulator can be installed so relief opening is 12" above the highest flue passage. Can you convert a forced air furnace with a secondary heating surface on the suction side of the air blower? No. Unless the heating surface consists of a single cylinder flue pope passing directly from the primary heat exchange to the flue collar and has a continuously gas tight welded joint. How do you check a heat exchanger? 1. Smoke in fire chamber (plug the flue outlet) 2. Light and mirror, check for cracks 3. warping and distortion of heat exchanger 4. Rust Spots 5. Gaskets on joints. How do you determine the firing rate of a replacement burner? 1. Heat loss calculations of the building 2. Input or output on rating plate 3. Nozzle size in the burner How do you calculate nozzle size in an oil burner? Gallons per hour time 1 US galon of oil (140 000 btu) ie: 0.75 h x 140 000 btu = 105 000 btu/h How many btus is 1 Boiler Horsepower? 33 475 btuh What are the three types of combustion chamber designs? 1. Updraft 2. Semi-revertible 3. Revertible - conversion prohibited What types of burners can be used in a revertible flue? Atmospheric is not allowed, Fan assisted can be used but must have spark ignition, pre-purge of combustion air and automatic valve with dual safety functions. What two types of atmospheric burners are usually used in conversions? Where would each be used? Inshot - usually used on oil fired appliances, must remove oil combustion chamber Upshot - usually used with coal fired appliances, must remove grate and ash pit doors. What are the products of complete combustion? 1. Carbon Dioxide 2. Water Vapour 3. Light 4. Heat What is the ultimate Carbon dioxide output in perfect combustion? NG - 11.9% LPG - 13.9% Where do you measure the flue gas temperature? Immediately upstream of the draft hood or barometric draft regulator. What is Net stack temperature? The difference between gross stack temperature and the ambient or surrounding temperature. How do you check combustion efficiency? Flue gas analysis is necessary to properly adjust Where is the neutral pressure point located? Located upstream of the draft control device. Neutral pressure point has _______ pressure below and ________ pressure above. Negative below and positive above. What needs to be ensured on a neutral pressure level? That it is installed at the correct height. What causes low resistance on the furnace flue passage? How can this be corrected? A higher then desired neutral pressure level. Add resistance by installing a neutral point adjuster. What must be done to a neutral pressure point adjuster once the burner input has been established? It must be permanently locked in place to avoid accidental adjustments. Is a barometric draft control deviced used for oil burners suitable for gas conversion? It is not. When would you use a single acting barometric draft control device? On an incinerator. Clause - 8.25 What is the difference between single acting and double acting barometric draft control devices? 1. Single acting can only swing one way, it will only allow air in from the structure. 2. Double acting swings both ways and will allow spillage of flue gases into the structure if venting is blocked or has enough downward pressure What is the minimum clearance from combustibles on a single wall vent connecter on a converted furnace? 9" Table 8.6 What is the minimum clearance in front of a boiler? 48" What types of burners are used in a conversion burner? Atmospheric, fan assisted, and power burner What happens if a blower belt is to tight? Stresses the motor out How many btu's are in one us gallon of oil 140000 What is the minimum gauge of steel required for flue outlet to the draft hood? 24 gauge clause 7.8.5 In the B149 code where do you find approved materials for joining single wall vent connectors? Under vent connectors clause 8.18.3 Before starting a burner what should be done? Check firing rate on plate and check venting What high limit setting should not be exceeded on a forced warm air converted furnace? 250 F clause 7.8.6 Following an oil to gas conversion where oil tank is in the basement what must a gas technician do? Remove fill pipe, cap or plug exposed fill pipe opening and leave vent intact. Clause 4.3.5 What are three undesirable products of incomplete combustion? Soot, aldehydes and Co. What is excess air? Air added to ensure complete combustion How is the high limit tested on a forced warm air furnace? Disconnect blower or block return air When flue gas analyzer is giving a reading where accuracy is in doubt what must be done? Compare to a known sample