Residential Heating Systems And Equipment (110104g) Flashcards
What is the heart of the HVAC system?
The air recirculation fan
What is a furnace?
A piece of equipment that transforms fuel into heat energy and distributes that energy through the HVAC system
What does BTU stand for?
British Thermal Unit
A BTU is defined as?
The amount of heat required to raise one pound of water 1 degree Fahrenheit or in HVAC one BTU will heat approximately 55 cubic feet of air 1 degree Fahrenheit.
Two different types of gas burners?
Inshot and upshot
What is the heating value of natural gas?
1000 btu
What is the heating value of propane?
2500 btu
The burning of any fuel requires what?
Oxygen
What is recommended humidity level?
Between 30 and 55 percent
What types of fuels do furnaces use?
Natural gas, propane, oil fuel, solid fuel aka coal wood.
What is used in high efficiency furnace in place of the draft hood?
Inducer motor
What are some types of safety controls for furnaces?
Highlimit
CAD sensor sense light
What type of furnace has the return air on top and supply air on bottom?
Counter flow
What type of furnace has return air on the side and supply air on top?
Upflow most commonly used
What type of furnace has both return and supply air on top of unit?
Lowboy furnace
What type of venting must be used on a high efficiency furnace?
Plastic 636 pvc
What type of furnace is 78% efficient?
Mid efficiency furnace
What type of furnace is 78% or lower?
Low efficiency
What type of furnace is 88% and above efficiency?
High efficiency
What is the heating value of electricity compared to BTUH?
1 watt = 3.413 BTU
What are two types of oil burners?
Vaporizing and atomizing
What oil burner is most commonly used today ?
Atomizing
What are solid fuels comprised of?
Wood, coal and wood pellets
Where are some locations where air is required to burn fuel in the combustion process?
Air shutters, gas burners
What is dilution air?
Air with contaminates that is cooled down in the draft hood before being expelled out
What is the main use of the heat exchanger?
It separates the air that circulates through the house from the products of combustion
What is a CAD sensor?
CAD is a cadmium sulfide cell.
What is used in place of a draft hood for fuel furnaces as well as oil furnaces?
Barometric damper
What does a furnace rely on even with an inducer motor to vent?
Buoyancy
What does a high efficiency furnace have that others don’t?
Inducer motor
Plastic venting
Secondary heat exchanger
What are two typed of fan coils?
Electrical or liquid medium
What does static electricity indicate?
There is not enough humidity
What are the types of humidifiers?
Pan evaporators
Bypass drum type
Bypass flow through
Atomizing
What type of pads does a pan evaporator use?
Wicking pads
What is a humidistat?
A moisture controlled switch
What are the three main components of a AC system?
Evaporator coil or A coil
Condenser unit
Compressor unit
What should never be connected to an HRV system?
Range hoods and dryer vent
What does HRV stand for?
Heat recovery ventilation
What is CFM?
Cubic feet per minute
What is the most common type of HVAC plenum system?
Extended reducing
What is combustion air?
Combustion air is the air an appliance needs to replenish, for the air to be exhausted so a vacuum effect doesn’t occur.
What are the byproducts of combustion?
Carbon monoxide
Oxides of nitrogen
Unburned carbon
Soot
What type of venting does a solid fuel furnace use?
A vent
I vent
Masonry chimney
Why do we need to vent buildings?
To remove excessive moisture and rid the house of combustion type gas
What does exfiltration mean?
The air that escapes through gaps in the building like openings around windows
What does infiltration mean?
Air that comes in through cracks in the building like drafts
What is the required gas to air ratio for natural gas and propane?
10 to 1
What is a cord if wood sold in?
4’ x 4’ x 8’
What kind of switch is a thermostat?
Temperature sensing
What is a radial HVAC system?
Octopus looking one that uses a counter flow furnace and is easy to install.
When does an extended plenum have to be reduced?
After a maximum of 24 feet
When is an appliance a direct vent appliance?
When there is a combustion air hook up
High efficiency furnaces are also know as?
Condensing furnace
Three types of fireplaces?
Built in
Free standing
Gas insert
Why is maintaining proper humidity in a house important?
-To prevent warping and splitting of furniture, wood work and hardwood floors
- prevent static electricity
- reduce levels of mites, bacteria, mold etc
What is major disadvantage of radial system?
You may encounter cold rooms because of heat loss due to length of pipe.
Where is a perimeter loop system not often used?
Residential heating systems above ground
What is a common problem with reducing extended plenum?
Loss of air speed,
What does a combustion air termination do?
It helps to keep cold air from dropping into the furnace room
What is main advantage of pleated filter over standard mesh?
Pleated filters provide protection against smaller particles
What refers to speed of air or how far air from fan will travel in one minute?
Feet per minute
What refers to the amount of air that a fan can move?
CFM or Cubic feet per minute
