Lesson # 14 : Learn How to Read Gauges.

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.

pexels photo 5835359

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

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