Improve Your Skills. Learn More about AC Pressures

welcome back ac lesson number 14 daydreams  normal and abnormal gauge readings let's start   with normal what is normal well according  to the pro-demand the following is normal that's what it says normally  functioning ac system remember   the four ingredients to normal can you fill  in the blanks the correct amount of blank   blank hitting on all cylinders good cooling of  the blank and something that starts with a c   you remember these are the four ingredients to  be normal fill in the blanks i hope you did well   the correct amount of refrigerant compressor  hitting on all cylinders and good cooling of   the condenser circulation of the refrigerant all  of these ingredients are just as important as the   first one the second one and the third one if any  of the ingredients are off it's going to affect   the performance of the cooling back to normal  it says it normally functioning ac system great   what is is this normal i'm  asking you is this normal   no and i hope you remember why we're special here  in texas extreme severe heat look at the pointers   the blue one can we round off that number 29 to a  30 on the red and we round that number off to 200   so yes we're gonna round off the two numbers the  blue number is 30 and the red number is 200. let's   look at this chart some of you might remember  that these pressures are affected by temperature   we'll start with the blue one the blue one is  between 25 and 35 puts us right at 30. that's   what this one is saying on the red we're off you  see the red the red arrow it's only saying 155.   if we try to get closer to 200 you see  the arrows now let's go with the red   the red arrow is pointing to a pressure on the  high side of approximately 200 but on the blue you   see what's going on it's not 30 anymore in fact if  you rounded it off it's like 45. i call it split   the difference here we're trying to get close to  what pro demand says is normal on this chart the   the blue arrow is indicating close enough to 30.  the red arrow well we're stretching it a little   bit but it's close enough to 200 but look at the  yellow arrow that's not corpus that's colorado   you don't even need air conditioning when it's 75  degrees out there right each vehicle is different   each specification is different throw in  some extreme operating heat conditions with dog days of summer and then you have  normal so what's normal good luck around here   here's some more tables let me try to simplify it   here on the yellow arrow that's where we  are right now in the summer summertime   we're easily between 90 degrees and 100. yes the  humidity makes it more difficult to cool us down   yes i'm pointing to the right one it's always  high humidity in the summertime the yellow   arrow we're always hot on the green arrow we're  almost almost always human the blue i'll keep   for the low side the blue says about 35 37 and  on the red we have some more pressure readings   here's some more readings let's see if we can do  anything with these this is one reading for one   particular vehicle this is another reading  for another vehicle they're not identical   each vehicle is different but we have to throw in  ambient temperature the yellow arrow close enough   the green arrow absolutely on the blue 50 could  be normal this thing about normal and abnormal   can get a little tricky let's go on there's no  question about it on the bottom temperature okay   the temperature affects the pressure the  higher the temperature the higher the pressure   i'm going to show you these  three different gauge readings   i'm going to start with what's called normal  another normal now i just got this off the   internet copy and paste but let's take a good look  at it right there under the blue gauge under the   red gauge everything says normal this represents  a normal working air conditioning system if we   now look at the blue pointer and we look at  the blue pointer sure it looks like 30 to me   the red pointer yes you'll have to be able to read  this who can tell where we are we're at 175 psi   this is normal that's what it says below the  blue below the red everything's normal here let's   look first below the red right away it says well  that's too high can you read the number we're on   the inner scale that's the psi the outer scale is  the metric unit we're at 425 that sure seems high   on the blue they can't make up their mind is  it high or is it normal if we read the blue   it's every bit of 50. you see this now  look at it i did not do a switch-a-roo   400 on the red 425 is what normal is the  ambient temperature is what very high   believe it have you figured it out our  pressures change with temperature especially   with extreme severe heat anything above  90 degrees is considered extreme severe   heat let's look at another one below the red it  says low below the blue they can't make up their   mind why can't their make up their mind because  we haven't plugged in the ambient temperature it   is abnormal is it low i'm not doing a switcheroo  look at it again on the red look at it that's 75   that's 75 psi if i was measuring temp if i was  measuring red pressure here in the summertime   that thing's half empty but look what it says it's  normal if the ambient temperature is what low it   goes both ways when the temperature is extremely  hot the pressure goes up when the temperature   ambient temperature is extremely low the  pressures go down more about normal you remember   these are the four ingredients to make normal  you should memorize them when we have all four   ingredients the correct amount it's nice and cold  of course you can't read that and i don't need   you to read it i'll explain at the top it says  normal now i hope you can count two four six eight   nine we're going to go over nine abnormal  readings look at those those are crazy look   at all those readings almost makes me busy  to look at all those numbers but let's go   on our first most common abnormal reading in  my opinion is this one starting at the top   low r134 charge the system is low on refrigerant  that's what the title says above the blue gauge   is low above the red gauge it's low everything is  indicating low over here we have a couple of more   symptoms on the blue arrow there's other things  to look at sight glass there it is a spike glass   i almost stopped mentioning these because they  were gone but i am so glad they're coming back   i haven't seen it yes i have i did see it  some of the newer vehicles on the liquid line   now have a sight glass you see that little round  glass on top of that drying element that's the   side clasp we used to use the side glass all  the time uh it was i couldn't understand why   they took it away the side glass was the easiest  way not only to tell that the system was low   but to hit your target charge as you were adding  the refrigerant you would look at that glass when   the glass was white that means it was low as  the charge got to a normal level the white   would turn to clear why is it low who remembers  is the refrigerant like gasoline it gets used up   and you got to keep adding it every year no why  is it low because of leaks leaks and more leaks   who doesn't believe it yet 80 percent of the  time the problem is the system has a leak   what leaks everything compressors lead connections  leak operators leak condensers leak fittings leak   hoses leak everything leak what part doesn't leak  everything needs any questions about low hong kong   that's our first abnormal gauge vegan the next  one yes we start to get a little bit more involved   at the top the blue arrows compressor malfunction  there's something wrong with the compressor   above the blue gauge the blue's too high  the red's too low you see them over here   what's wrong with it where they're telling  us that we have an internal compressor leak   or it's mechanically broken who remembers  what goes wrong with the compressors   well they're like an engine and they wear  out we have internal leakage here here   the ring has decided to leave the groove but  remember is why the teflon rings decide to leave   the groove because they're overheated and they're  melting this particular image shows plenty of oil   on the moving parts compared to this one this one  doesn't have any oil and it's easy to understand   why they wear out they're like engines that's  not going to go away they're still the same   they're going to wear out because they  don't have oil they're going to wear out   because they overheat or they're going  to wear out because of a combination   yes that's an ac compressor off a vehicle what a  mess let's go on i gets a little more tricky here   insufficient cooling of the condenser or  this is two things we're covering two things   insufficient cooling of condenser is one problem  or refrigerant overcharge is another problem   now above the gauges where are they let's keep it  simple above the above both gauges it says high   the pressures are high and at this  point there's two things that will make   both pressures too high one is the condenser is  not getting cool very well it's not sort of kind   of nice it's an essential part of the process we  have to remove heat from the refrigerant it's part   of the process you should have an idea why well  condensers get dirty nobody cleans them except me   bully fans guarantee they're going to  wear out because if you know inside   inside all vc motors are the brushes  these guys are going to stop working   and now the air conditioning is going to be  affected and the pressures go too high here's a   wiring diagram we can have problems with the relay  and the protection and some of the switches other   problems that can cause insufficient cooling of  the condenser is that the fan clutch is slipping   these guys don't last forever they might be  spinning but they're not spinning fast enough   when the engine is hot and you're in stop and  go driving these fan clutches should hardly slip   the only time they're supposed to slip is when  you're going down the interstate 75 miles an   hour you have a ton of ram air the engine  compartment and passenger compartment is full   that's why we slip it who knows why we  slipped the clutch there's a couple of answers   one is to improve fuel mileage another one is to  quiet the operation these guys don't last forever   dirty condensers damaged condensers 30 condensers  it's the same thing whether you're working on a   house or a car this is an important part of the  process that's what happens when the pressure   guess what happens to the pressures when the  condenser does not get pulled they go high   and now we're destroying the compressor  we're melting the rings we're   they're wearing out the compressor  next one we're still talking about   the same thing insufficient cooling of  condenser or refrigerant over charge   how does an ac get overcharged over charge means  too much freon well i'll tell you how rookies   you gotta love them you trust that guy never in a  million years grace monkeys they used to call us   that's not real that's a hollywood actor or  put some more the temptation is overwhelming   to put a little extra refrigerant is not going  to make it cold ac pro is no help to the rookies   more is not better it's very easy to overcharge  the temptation is overwhelming and the system   will take it as fast as you put it in let's go  on next what does it say it says poor refrigerant   circulation we're going over all the problems  the refrigeration system can have the first one   i showed you was well it's low on prima  freon the second one i showed you while   the compressor is bad the next one i showed  you either we're not cooling the condenser   or somebody to put too much free on this is  part of the ingredients we have poor circulation   look at the gauges they're doing something  funny the blue gauge has gone into negative   vacuum now this is still a normal system  it's got the normal amount of refrigerant   we now have another problem it's not on the  on the top of the list but it is on the list   you should ask yourself and maybe you  have an idea what causes poor circulation   we have certain several answers you've  seen some images i'm going to show you   some more we have dirty tubes dirty valves  hooked up dryers and restricted condensers   of course i have pictures there on the left  the new tube and then the one next to it   that's not special hollywood makeup  i'm sure that's actual failure   who knows what that is that's probably mostly  piston material teflon and that expansion valve   they get restricted the passages are very small  it doesn't take many deposits from the compressor   to plug it up whether it's the block style or the  90 degree style they're going to get restricted   guts of the compressor whether it's metal or  teflon or whatever it is it's going to wind up   at the tube at the valve what are we looking  at we're looking at a cutaway of the condenser   why do i mention it and i told you last time the  new condensers are high efficient the passages are   tiny when we have catastrophic failure of the  compressor it's pretty much standard procedure   to replace the condenser we used to flush  them but nowadays the passages are so small   we don't even try dryers now those are the  ones get plugged up the one on the right   the red one that's the dryer i know the color's  off but they're at the bottom i want you to notice   that's a screen and what happens is when the  screen gets dirty what we're doing is identifying   the major proponents four of them that are likely  to get plugged up or restricted the sub says in   the discharge in the liquid line no they don't  get restricted evaporators don't get restricted   there's only four things that get restricted  and try and understand now let's go on and   split some hairs you see the difference now now  they're saying there's no circulation as compared   to poor circulation it's almost the same thing  here notice the the blue gauge it's in a vacuum   whether it's poor circulation or no circulation  the gauges are going to act real funny on the blue   sometimes we're getting down to the list here it's  possible moisture you have moisture in the system   moisture is in the air the refrigeration system  all of them have not cannot tolerate moisture   when moisture hits that expansion valve what  happens is it freezes instantly now the way you   can spot it over here above the blue the blue is  on the left the low side read the word slide above   the blue gauge one minute is normal and the  next minute it's in a vacuum what's happening   well it's working normal normal normal and the  moisture it doesn't happen every single time   it's a little hard to catch it right at the  incident occurs sometimes the ac is working   man is working well and all of a sudden it goes  hot and then it goes cold and then it goes high   when you have a system that one minute it works  and the next minute it doesn't and what i mean   works i mean cold and when i say it doesn't it's  hot one minute is working the next minute it's not   what's wrong with it it's possible it has moisture  we go out of our way to make sure that there's no   moisture in the system mostly by pulling a  vacuum the more technical term is evacuation   the important part this is not the most common but  it's on the list we're headed toward the last one   the last of the list if you have moisture the  system works and works well and just out of   nowhere it turns hot so it's possible the system  has moisture in it starts off normal they're   really milking it here they're trying to cover  every single aspect air rookies here we go again   when we're charging the system whether we're using  the gauges or the station both of us the station   at and ourselves we take steps to purge air out  of our service hoses it is possible to have too   much air in the system air is not cold brianne  is cold we don't want air we don't want moisture   we want that good juicy refrigerant here our last  one or is it wait a minute what am i showing you   here when you have air on the system above both  gauges look at it they're high now that should   remind you of this one there's two things the  condenser is not being cooled somebody over   charged it you see above the gauges it says hi  i'm not pulling a switcheroo this is what happens   we actually have four things support them three  we have three things if there's air in the system   the readings are too high if there's insufficient  cooling of the condenser buy if we have too much   refrigerant the readings are too high let's go  on i believe this is the last one something about   the expansion valve improperly mounted or here we  go two things now wait a minute again i was right   there are four things that will cause high high  high high we can have them both high there's air   in the system we can have them both high there's  insufficient cooling of the condenser we can have   them both hives somebody put too much refrigerant  we can have them both high if the expansion valve   is not mounted correctly or we have the sensing  ball the sense involved this particular type of   expansion valve needs to know what the temperature  is of the evaporator you see the yellow arrow the   sensing bulb has to be securely mounted to the  outlet of the evaporator pictures are better the   blue the yellow arrow on top that's the beginning  of the sensing bow the yellow arrow on the bottom   that's the sensing ball the sensing bulb has to  be securely attached to the out of the evaporator   and some of this tar tape you see on this  particular image we have the same thing we have   the same sensing bulb but it's under a tar tape  this looks like this might be a good place to stop

Channel: Old Mecanico

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Id: XGBAxSDTIoU

Length: 24min 40sec (1480 seconds)

Published: Wed Jul 08 2020