Heating Period 1 (CND) Flashcards
I.B.R.
Institute of boiler & radiator Manufacturers
Min. Boiler Pressure?
12 Lbs
Best describe the amount of energy required to raise the temp. of 1 pound of water through 1 F?
BTU
Boiler limited to a max working pressure of 30 psig to 15 psig?
Low Pressure boiler
Indicate pressure & temp. within a hot water boiler?
Combination Gauge
Completely closed tank containing water & air. Allows expanded water to enter & leave?
Expansion/Diaphragm tank
Any material used to store heat energy or the affinity for heat energy?
Thermal mass
A float/Probe operated device used to shut down the fuel burner when the water level in the boiler drops below operating level?
Low water cut off
A device with a globe valve pattern that is used to reduce city water pressure?
PRV (Pressure Reducing Valve)
First supplied , First returned is a good description of?
Direct Return System
First supplied, last returned is a good description of?
Reverse return system
Monoflow tees are used on a?
One pipe system
Transfer of heat through a solid is known as?
Conduction
Transfer of heat from one object to another through an intervening space?
Radiation
Transfer of heat through a liquid or gas?
Convection
Heat required to change the state of water is known as?
Latent Heat
Energy required to raise temp. without changing state s known as?
Sensible Heat
The mas operating temp & pressure of a low temperature hot water boiler ?
120 C (250 F) 1100kpa (160psig)
How are low temp. boilers rated?
BTU/h or EDR
Definition of net rating?
Amount of heat energy available at the heat transfer units
What two large categories do hot water boilers fall under?
Pressure & temperature
Low temp boilers are covered under?
A.S.M.E. Section IV
Could be adopted by a legal jurisdiction and made into a law?
Code
What is the BTU value of an EDR? (Hint: Steam_____, Hot Water_____)
Steam 240 BTU/hr, Hot Water 150BTU/hr
Definition of boiler input?
Amount of energy consumed by the boiler
Cast iron sectional boiler could be classified as a ?
High mass boiler
Hot water boiler that can directly heat domestic water>
Copper tube boiler
Fire tube boiler is classified as a ?
High mass boiler
What can cause coil damage in a low mass boiler?
Little to no water flow
What is the purpose of a boiler operating control?
To control the normal temperature range of a boiler
A device that protects the boiler from excessive temp?
Limit Control
what mandatory device is required on a coil type boiler over 400000 BTU/hr?
Flow Switch
What device can be installed to protect a hot water boiler from low water level?
Probe type low water cut off
A device that compensates for expansion & contraction of the water in a hot water boiler?
Diaphragm/Expansion Tank
You would find a sight glass on what type of boiler?
Steam Boiler
pressure reducing valve is located on what type of boiler?
Hot water boiler
What is the purpose of a wild loop?
To prevent the pump from dead heading
What method of heat transfer does finned tube baseboard utilize in heating?
Convection
What type of radiator valve should be installed to prevent unauthorized use?
Lock shield radiator valve
Process of manufacturing pipe?
Cross linked
The piping system in which the heating transfer units are supplied by special tees?
One pipe system
What is the purpose of a flow control valve?
to prevent convection currents in a heating system
Where is the best location for a circulator?
downstream from the compression tank
What two variables do you find on a pump curve?
head and flow
What function does a circulator provide in a hot water heating system?
moves water within the system
What device removes gases directly and air from the water leaving the boiler?
boiler scoop
Why is it important to remove gases from a hot water heating system?
to prevent air binding in the system
What are the two primary considerations when locating air elimination devices?
temperature and pressure
What is the purpose of a zone valve?
to provide control of heat emission
What is the purpose of a balancing valve?
to adjust flow rates to each heat transfer unit
a good choice for use as an isolation valve?
ball Valve
What is the major disadvantage of a two-pipe direct return piping system?
hard to balance flow to each heat transfer unit
What is a major disadvantage of a one-pipe system?
end heat transfer units receive cooler water
What is a major disadvantage of the series loop piping system?
limited heating capacity for each circuit
What is the name of the piping system in which the water has approximately the same distance to travel for each heat transfer unit?
two-pipe reverse return
What is the name of the piping system in which the heating transfer units are part of the piping?
series loop
Which of the following copper tube is not approved for hydronic heating?
Type DWV
Which of the following piping materials are suitable for hot water heating?
steel pipe, Type M copper tube, PEX tubing
Which term best describes a boiler limited to a maximum working pressure of 30 psig (water) or 15 psig (steam)?
A low pressure Cast Iron boiler
A float-operated device used to shut down the fuel burner when the water level in the boiler drops below its operating level is called a?
Float type low water cut-off
What is the maximum operating temperature and pressure of a low-temperature hot water boiler?
120ºC (250ºF), 1100 kPa (160 psig) or conventional cast iron 207 kPa (30 psig)
Which of the following is a definition of net rating?
amount of heat energy available at the heat transfer units
What problems can occur in a conventional boiler if the flue gases are cooled to their dew point?
draft hood spillage or damage caused by corrosive condensate
What code covers the fabrication, installation and inspection of boilers?
ASME code (American Society of Mechanical Engineers)
What can cause coil damage in a low-mass boiler?
low or no flow through the heat exchanger
What is the purpose of a safety relief valve?
to protect the boiler and system from excess pressure
What is the purpose of a boiler operating control?
to control the normal temperature range of a boiler
What device is used to maintain a minimum pressure within a system?
Pressure Reducing Valve
Which one of the following items would you find on a hot water boiler?
1) pressure operating control
2) sight glass
3) expansion tank
4) equalizer line
expansion tank
Which one of the following items would indicate that you are looking at a hot water boiler and not a steam boiler?
1) makeup water line
2) backflow preventer
3) pressure operating control
4) pressure reducing valve
pressure reducing valve
Which one of the following items would you find on a steam boiler?
1) line scoop
2) diaphragm tank
3) flow switch
4) sight glass
sight glass
What causes convection currents?
different air densities
What method of heat transfer does finned tube baseboard utilize in heating a room?
convection
True or False: Free-standing cast iron radiator units produces significant amounts of radiated heat?
True
What method of heat transfer is utilized by a plate heat exchanger?
conduction
How is finned tube baseboard rated?
BTU per foot per hour based upon supply water temperature, flow rate and entrance air temperature of 65ºF`
How is the heat output of finned tube baseboard controlled?
by adjusting the damper
What effect would raising a fin vector above recommended installation height have on the heat output?
Heat output would be reduced.
Atmosphere is described as?
14.7 psia, 29.92 in/hg & Pressure at sea level
What material is commonly used to construct sectional boilers?
Cast Iron
What is the purpose of the safety relief valve?
To protect the boiler and system from excess pressure
What is the purpose of the boiler operating control?
To control the normal temperature range of the boiler
What is needed to size a pump?
Head & Flow
What is the place where the expansion device connects t a hydronic system called?
The point of no pressure change
Water is most dense at?
4C or 39.2F
How many BTU’s of latent heat must be added to one pound of water to change it to steam?
970 BTU’s/per pound
For residential cast iron steam boilers, the stem pressure relief valve is set to discharge at a max. of?
15 psi
Velocity energy of a circulator is created by?
Vanes of the impellor
What causes convection currents?
Different air densities
True or False: If two pumps are in series, the pressure is additive & the flow remains constant?
True
U.L.C stands for?
Underwriters Laboratories of Canada
ASTM stands for?
American Society of Testing & Materials
CGA stands for ?
Canadian Gas Association
True or False: In a one pipe counter flow steam system, the condensate and steam flow in opposite directions?
True
All boiler make up water must be protected from cross connections by?
Approved backflow preventer
True or False: If latent heat is taken away from water it will expand?
True
What device cycles a steam boiler on and off?
Pressure troll
