HVAC Flashcards
What is it called when Vapor and liquid exist at the same time in the same coil?
Saturation
Explain a compressor component.
Low temp low Vapor flows into compressor. Compressor compresses it and turn it into high temp high Vapor. Compressing creates heat, and pressure and heat are directly related. If temp goes up, pressure goes up.
What is the step after compression, what does it do?
High pressure high temp Vapor travels from compressor through condenser coil. The fan blows air on condenser coil and cools the temp. The Vapor turns into a high temp liquid and continues to flow to liquid receiver.
What does the filter drier do?
Removes excess water and contaminants. Water mixed with refrigerant oil creates alcohol and acid.
High pressure high temp liquid travels from liquid receiver to ________
Thermostatic expansion valve (TXV)
What is a TXV, what does it do?
What type of liquid travels from the TXV?
Low pressure low temperature liquid.
What is the function of the evaporator?
Low pressure low temperature liquid travels from TXV into the evaporator coil. Evaporator coil absorbed heat from inside and turns the liquid into a Vapor. Low temp low pressure Vapor flows back outside to the compressor.
What is the term for where low temp low pressure Vapor comes out of the evaporator?
Superheat.
What is the purpose of the TXV bulb? Where is it mounted?
It reads the temperature of the super heat, it is connected to the TXV and depending on if the Vapor is too hot or too cold the TXV will release more or less liquid. It is mounted outside of the Vaporator.
Electric furnaces are made of
Blower heater combination.
Heater resistance elements are layered in 5kw rated pieces to reduce light flickering. Blows hot air up through ducts, cold air back out to return
Where are furnaces usually installed?
Basements or crawl spaces
What is a furnace heat exchanger for? How does it work?
To keep products of combustion seperate from circulated air.
How does a furnace work?
A fan draws air from living room/dining room, blows through heat exchanger, blows out into rooms. Heat exchanger exhausts dangerous fumes through flue.
How efficient are furnaces?
70-80%
