Air conditioning Testing and service part A Flashcards
when exposed to exposed flames refrigerants that contain fluorocarbons break down and produce
dangerous poisonous vapours
what is the maximum filling limit for any refrigerant container is
80% of its internal volume
what is a vapour analyzer able to do
identify and measure the purity of air conditioning system refrigerants , determine the percentage of air contained in the air conditioning system , prevent the filling of refrigerant recovery bottles with cocktails
what color is the high pressure side
red
what color is the low pressure side
blue
what pressure range would be present on the high pressure side
0 - 500 psi
what pressure would be present on the low pressure side
0 - 150 psi
what could the yellow hose on the gauge set be used for
recover refrigerant from the air conditioning system.
pressure test ( leak check ) with nitrogen.
evacuate air and moisture from the system.
add oil to the air conditioning compressor with oil injector.
recharge the air conditioning system with refrigerant.
what is the purpose of using a high capacity vacuum pump when servicing an air conditioning system
to remove the moisture and air that is hidden in the hoses and components of a air conditioning system
what can a micron gauge be used for
to measure the level of vacuum that has been reached in the air conditioning system as its being evacuated
how can you check the accuracy of the bubble crimp produced on a bead lock fitting that looks regular
you can check it with a micrometer
what would you use to fix the bent fins on a air conditioning condenser
a fin comb
what would a damaged or loose Schrader valve core cause
a refrigerant leak large enough to render an air conditioning system useless in a matter of hours
what is the first step to trouble shooting an HVAC system
visual inspection
properly operating air conditioning system temperatures and pressures vary with
ambient temperatures - humidity levels and condenser size
what will a blockage to refrigerant flow ( internal restriction ) cause inside the air conditioning system
low system pressure will result
what would a malfunctioning air compressor cause
higher than normal low side pressure readings
lower than normal high side pressure readings
high temperature readings in HVAC duct airflows
what could two or more refrigerants mixed inside the same air conditioning system cause
high pressure readings
what would dirt and debris lodged in the condenser fins cause
higher than normal pressure readings
what happens when refrigerant escapes or is released into the atmosphere
its temperature drops instantly . and can cause frostbite
what is the only way to measure how much refrigerant is in an air conditioning system
remove all of the systems refrigerant and charge and weigh it
why must you never use shop air when pressure testing the air conditioning system
because R - 134a and oxygen in compressed air form a combustible mixture
when checking for a refrigerant leak by watching the gauge readings
if they drop as little as 1 psi over five minutes the air conditioning system has a leak and must be repaired
when using nitrogen to check for leaks never exceed
250 psi low pressure lines may rupture
all three shut off valves on a gauge set must have
a shut off valve within 10 inches of the ends
how often should a truck HVAC system be inspected
every six months
a correctly operating thermostat should start to open
2 - 5 degrees below its rated temperature
what would an overcharge of refrigerant cause
both pressure readings to be high
what is compressor slugging
when the compressor fills with liquid refrigerant due to failing compressor components
when doing a visual inspection of a temperature sensing bulb it must be
securely attached and insulated to the evaporator outlet sensing line
