ac turns off at idle
06-23-2006, 06:32 PM
#41
Originally Posted by TS6
Wrong, wrong, wrong. Pressure does not equal volume. Checking static pressure will only tell you if it has any refrigerant at all in it. Refrigerant pressures fluctuate with temperature, not volume. You can have a canister with 30 lbs. of refrigerant in it and one the same size with 10 lbs. in it, both will read the same pressure if they are the same temperature. Do you have a T&P chart for 134a? If not, how do you know what static psi would be at 80 degrees?
Anyway, just go to autozone and buy the 134a that comes with a gauge, $16 last time I bought one. Its an idiot gauge, but it works. Or go to a local shop, they will check your charge for pretty cheap. Some of the local places here will check and charge the system for like $40 up to 2 lbs.
Anyway, just go to autozone and buy the 134a that comes with a gauge, $16 last time I bought one. Its an idiot gauge, but it works. Or go to a local shop, they will check your charge for pretty cheap. Some of the local places here will check and charge the system for like $40 up to 2 lbs.
If you pick up a bottle of freon, you'll notice it feels like there's a liquid inside, which there is. You can pump freon into a 1/2 full bottle for 10 minutes, let it sit, then check the pressure. It will be exactly the same regardless of it being 3/4 full or 7/8th full. Inside the bottle, the freon is at a saturated liquid/vapor state.
Instead of increasing in pressure, the gas condenses to a liquid given the right temperature.
06-25-2006, 11:04 AM
#42
Originally Posted by TS6
Wrong, wrong, wrong. Pressure does not equal volume. Checking static pressure will only tell you if it has any refrigerant at all in it. Refrigerant pressures fluctuate with temperature, not volume. You can have a canister with 30 lbs. of refrigerant in it and one the same size with 10 lbs. in it, both will read the same pressure if they are the same temperature. Do you have a T&P chart for 134a? If not, how do you know what static psi would be at 80 degrees?
Anyway, just go to autozone and buy the 134a that comes with a gauge, $16 last time I bought one. Its an idiot gauge, but it works. Or go to a local shop, they will check your charge for pretty cheap. Some of the local places here will check and charge the system for like $40 up to 2 lbs.
Anyway, just go to autozone and buy the 134a that comes with a gauge, $16 last time I bought one. Its an idiot gauge, but it works. Or go to a local shop, they will check your charge for pretty cheap. Some of the local places here will check and charge the system for like $40 up to 2 lbs.
Yes I do have a T&P chart and I am also EPA609 Certified and have a whole lot of paperwork on A/C and if all thats wrong then damn you guys are pretty good but I highly doubt thats all wrong. But my bad I was so wrong. Peace
06-25-2006, 11:51 AM
#44
If you are epa certified you should know better. You should know that pressure doesn't equal volume. So yes, you are wrong. How can you even say that when you have (and presumably know how to read) a T&P chart? That chart bases pressure off TEMPERATURE, not volume.
And BTW, I'm epa certified as well, and nate certified.
And BTW, I'm epa certified as well, and nate certified.
06-25-2006, 12:11 PM
#45
Originally Posted by Jpr5690
volume is related to pressure given a constrained size
mabye the pressure change is verry little in the can but its there..its phsyics
mabye the pressure change is verry little in the can but its there..its phsyics
At a certain point yes the pressure can come down if volume comes down. But thats when the volume is very low for a certain size container. I buy refrigerant in 30 lb jugs. I promise you that if I have 3 cans, lets say one has 10 lbs, one has 20 lbs, and one has 30 lbs, they will all read the same pressure if they are the same temperature. Now if I have maybe 1 lb or less in a can the pressure can be less than it should be, but thats extreme. In this situation, of this guys A/C system was low enough on charge to read low pressure at ambient then his A/C wouldn't even come close to working, and he says it works at least sometimes. So it was a bad suggestion regardless, especially from someone who supposedly knows what he is doing.
06-25-2006, 04:33 PM
#46
I never said volume equals pressure, you are obviously assuming things. But as stated above the static pressure will give him some indication of whats going on in the system. And plus if he cant get the A/C to kick in what good are the operating pressures beings he wont have any. And how do you know his pressures wont be high, he could have moisture or air in the system and that will make his static pressures way high and that could also be why its not kicking in if his high pressure switch is shutting it off. Static pressure is obivously not any means of accurately checking the system but it will give him some indication if he wants to try and fix it himself, and im trying to do instead of questioning other peoples intelligence. If anything he should get a refrigerant identifyer, to see what amount of charge he has and if it has moisture or anything in it but I doubt he has access to one. But while your talking about your volume and pressures maybe we can try and DIAGNOSE whats wrong the guys car.
Have you gotten any guages or anything yet and hooked them up to your car? If so what kind of pressures are you getting?
Have you gotten any guages or anything yet and hooked them up to your car? If so what kind of pressures are you getting?
06-25-2006, 11:18 PM
#47
Originally Posted by Jpr5690
volume is related to pressure given a constrained size
mabye the pressure change is verry little in the can but its there..its phsyics
mabye the pressure change is verry little in the can but its there..its phsyics
The pressure will be the same in the system wether there is 1lb of freon or 10lbs of freon.
I agree if you hook up the guages while the car isn't running and get 30psi, you've got problems, this means there's not enough in the system. You can pump freon in and it will hit a certain pressure then the pressure will stop climbing. From here on out, you're going to stack liquid in the system untill it is full as if you were putting water in a bottle.
07-07-2006, 08:30 AM
#54
Launching!
Originally Posted by slowpoke96z28
pressure, temperature, and volume are all related. if you change one, the other two will change also. like Jpr5690 said,"its physics".
P=Pressure
V=Volume
T=temperature
n and r are constants and I don't remember their values as they change for different gasses if I am not mistaken.
If Pressure or Volume increase then Temperature has to increase as well to keep the equation balanced. So if Temperature increases and Volume is fixed then the Pressure will increase.
07-07-2006, 09:21 AM
#55
Originally Posted by jdperk-86elco
The equation for this is PV=nrT, a good equation to know.
P=Pressure
V=Volume
T=temperature
n and r are constants and I don't remember their values as they change for different gasses if I am not mistaken.
If Pressure or Volume increase then Temperature has to increase as well to keep the equation balanced. So if Temperature increases and Volume is fixed then the Pressure will increase.
P=Pressure
V=Volume
T=temperature
n and r are constants and I don't remember their values as they change for different gasses if I am not mistaken.
If Pressure or Volume increase then Temperature has to increase as well to keep the equation balanced. So if Temperature increases and Volume is fixed then the Pressure will increase.
