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57 Cards in this Set
- Front
- Back
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What is a boiler? |
A vessel designed to transfer heat from from a primary heating source to a fluid (usually steam or water) |
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When the boiler is heating steam, what is it used for? |
Power, processing or heating purposes |
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When the boiler is heating water, what it is used for? |
Heating purposes or domestic hot water supply. |
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What are the most common heat transfer fluid? |
Steam and water |
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Boiler are initially classified by what factors? |
Whether they're Stationary, mobile, or portable, and the fluid they use to transfer heat. |
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Low pressure heating boilers operate at what PSI? |
15 PSIG or less |
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High pressure power boilers operate at what PSI? |
More than 15 PSIG |
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What is ASME Section 1? |
Power boilers |
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What is ASME section 4? |
Rules for construction of heating boilers |
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What is ASME section 6? |
Care and maintenance |
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What is ASME section 8? |
Rules for construction of pressure vessels |
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Piping code B31.1 is for? |
Power piping |
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Piping code B31.3 is for? |
Process piping |
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What type of boiler consists of a firebox that is not entirely surrounded by water? |
Firebox boiler |
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What's the difference between a fire tube and a water tube boiler? |
Fire tube boilers have products of combustion within the tubes. Water tube boilers have water within the tubes |
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What type of boiler consist of a shell containing a furnace and straight tubes through which the hot gases from combustion travel? |
Firetube boilers |
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What type of boiler consists of an arrangement of drums and headers interconnected by tubes, where water circulates through the tubes and the products of combustion are outside the tubes? |
Watertube boilers |
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What method of draft control uses no fans? |
Natural draft control |
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What method of draft control uses a fan to force air into the Firebox? |
Forced draft control |
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What method of draft control uses a fan connected to the boiler flue to create a low pressure area at the boiler outlet, causing air to be drawn in at the front of the firebox? |
Induced draft control |
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What method of draft control uses a combination of forced and induced draft fans to keep the pressure in the Firebox constant? |
Balanced draft control |
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Describe internally fired boilers. |
The furnace is located in a shell, completely surrounded by water. |
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Describe externally fired boilers |
The furnace is outside the shell, surrounded by brickwork, it is not surrounded by water. |
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Define input rating of a boiler |
The rate at which fuel is supplied to the boiler |
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Define gross output rating of a boiler |
The amount of heat energy available at the boiler nozzle. |
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How many BTUs are in 1BHP? |
33475 |
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What is net rating? |
The amount of heat available at the point of usage or at the heat emission unit. |
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How do you calculate the effectiveness of a boiler? |
Gross output/input ×100 |
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How are cast iron and copper heating boilers rated? |
Net rated |
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How do you calculate net rating? |
Gross rating ×75% |
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What does wetback mean? |
All tubes are submerged by water |
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What does dryback mean? |
Top 2 or 3 tubes aren't submerged in water. |
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What type of watertube boiler has one upper drum that is connected to two lower drums with bent tubes. |
Type A watertube boiler |
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What is the most popular type of watertube boiler? |
Type D |
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What type of watertube boiler is symmetrical, qell balanced, and compact? |
Type O watertube boiler |
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What type of boiler is the least efficient, but useful with an inexpensive fuel source? |
Firebox boilers |
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The ability of a boiler to respond to changes in steam or hot water demand is referred to as what? |
Load tracking ability |
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A firetube boiler is considered high mass or low mass? |
High mass |
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A watertube boiler is considered high mass or low mass? |
Low mass |
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What type of boiler has no steam space? |
Flash boilers (monotube boilers) |
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Tankless water heater is another term for what? |
Flash boiler. |
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How is foam created in a boiler? |
Oils and other suspended solids from the metal build up in the water |
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What happens when foam is present in a boiler and what is the reaction called? |
It can create a low-pressure area that that can induce particles or slugs of water to leave the surface and become entrained in the flow. This is called priming or carryover. |
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What is the main problem with oversized boilers? |
The boiler will cycle on and off more frequently, consuming lots of fuel with no heat transfer leading to increased fuel costs. |
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What is the main problem with undersized boilers? |
They do not provide enough heat. |
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Steamfitters may be responsible for setting up and servicing boilers with less than how much heating surface? |
100ft² |
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Large fluctuations of the operating boiler water line is a sign of what? |
Foaming or priming |
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What is an optimal pH for boiler water? |
Between 7 and 9 |
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High pH in water may react with particles to create what? |
Foam |
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If CO2 is absorbed into the condensate what does it create and what happens to the return lines? |
Carbonic acid is produced and it will result in internal corrosion |
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What should you do if there is no visible water in the gauge glass? |
Blow down the gauge glass, if the water does not return quickly, shut down the boiler immediately. |
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What causes scaling? |
The addition of makeup water, that is not pure, to the boiler |
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What problems occur with scaling? |
It can reduce heat transfer efficiency, and create hot spots if it builds up too much. Hot spots can soften the metal and cause the boiler to rupture. |
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The water level in the sight glass should be matching the water level inside the boiler. This is referred to as what? |
The static water line. |
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Blowoff is required for what? |
To control the concentration of solids in a boiler. |
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Where is the blowoff connection on a boiler? |
At the lowest point. |
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What procedure is used to clear lines that have been plugged while removing sediment and sludge? |
Rodding |
