AC problems

[dripley]

My AC has been working so far this yearbut is getting a bit warmer. It was hitting about 40* out the center vents but has crept up to about 55*. I put gauges on it and static pressure was about 80 psi. Started the motor and the high pressure is about 140 but the low pressure is pretty much pegged and bouncing.

The compressor clutch is engaged, ambient temp 85* and center vents at 55*.

Low pressre switch? Thought that should shut the compressor down.

Expansion/orifice tube maybe?

[Mopar1973Man]

I'm going to guess orifice tube. Nothing to build pressure so it just pumping the pressure to the lo side.

 

[dripley]

Just drove to get some non ethanol gas and the center temp got down around 50 I figure thats just driving it. One other thing I have always thought was bit strange is any time I get a discharge of refridgerent is how oily it is. Seems to be that way out of the can. I use Wally world 134a. There is nothing on the can that says there is any oil in it but it makes me wonder. But if what I know is right if there was to much oil in the system it would not be cooling worth a damn either. 

[Guest ibmobile]

I have to agree with Mike that the orifice tube is blocked.

Oil can't get into the system unless you added it. There is no oil in a can of 134a unless it says so, like a 2oz oil recharge can.

 

[Mopar1973Man]

That shouldn't have happened but I fixed the permissions. 

Edited May 20, 2019 by Mopar1973Man

[dripley]

26 minutes ago, Guest ibmobile said:

I have to agree with Mike that the orifice tube is blocked.

Oil can't get into the system unless you added it. There is no oil in a can of 134a unless it says so, like a 2oz oil recharge can.

 

Well I have one. Reckon it will hurt anything for a few days? If so I might have to take with me and do it at the job.

 

The guest IBMobile thru me off a bit.

[Haggar]

Rip,

 

I wonder if your gauge set is starting to mess up.....

 

There should be no way for you to nearly have high side pressures on the low side.......   That is wrong on so many levels....  especially when you say that there is still cooling going on.  (ambient to 55 is some cooling...)  (if there was no expansion device, there would be very little pressure difference between suction pressure and discharge pressure, but there would be NO cooling.)   A plugged expansion device gives you  high high side and low low side pressures...... 

 

80 static doesn't sound bad. 

 

Double check the gauge set that both valves are closed.  remove the yellow hose, (or at least depress the schrader) and see if you have pressure there.  there should be NO pressure on the yellow hose when both valves are closed. (though both gauges should read their respective line pressures.)

 

Hag

[Mopar1973Man]

17 hours ago, Guest ibmobile said:

I have to agree with Mike that the orifice tube is blocked.

 

If the tube was blocked the pressure would of spiked past 400 PSI and triggered the safety switch. The orifce being missing would pump the same pressure on both sides. Being there nothing to hold pressure back. It's hard to tell with the lo side gauge being way past 120 PSI. Since there is nothing to hold back pressure and spray the freon into the lo side the temperature is going to be super poor. 

[dripley]

42 minutes ago, Haggar said:

Rip,

 

I wonder if your gauge set is starting to mess up.....

 

There should be no way for you to nearly have high side pressures on the low side.......   That is wrong on so many levels....  especially when you say that there is still cooling going on.  (ambient to 55 is some cooling...)  (if there was no expansion device, there would be very little pressure difference between suction pressure and discharge pressure, but there would be NO cooling.)   A plugged expansion device gives you  high high side and low low side pressures...... 

 

80 static doesn't sound bad. 

 

Double check the gauge set that both valves are closed.  remove the yellow hose, (or at least depress the schrader) and see if you have pressure there.  there should be NO pressure on the yellow hose when both valves are closed. (though both gauges should read their respective line pressures.)

 

Hag

The gauges are HF. Heard they are not the greatest so they could be the problem.

 

But thinking back I am pretty sure I had the gauge valves open along with the  the valves on the hi and lines.   Had the yellow hose connected to a refrigerant can and that valve off. I think I will have to start over this coming weekend. Now to go to my corner.

[Haggar]

Drip,

 

That's it if the valves were open.  To the gulag with you!!!   (you have not reached "off with your head" level yet.)

 

Both have to be closed.   When you want to add some juice , only open low side and watch the sight glass, should be bubbles not all liquid.  (yeah low side theory says you could add liquid, but I am totally paranoid)   (don't even consider adding high side with the small cans, I don't think they can take the pressure!  You will be approaching the "off with your head" level there though... )

 

Cheers

 

Hag

[Mopar1973Man]

The only way I add anything to the high side is if I know exactly how much freon I need to add. Say I was rebuilding my A/C system and it was pulled down on vacuum and ready to go. With the engine off, I would open the high side red knob and flip the cans up-side-down and place is a tub of hot water. Pushing all the contents out into the hi side as a liquid. This is the only time the high side should be used.

 

Then for typical lo side touch ups then I have the engine running and A/C on MAX A/C and high fan. Then watch the lo and hi side pressures. I typically keep adding till I see roughly 35 PSI lo side and about 210 to 250 PSi hi side. The freon should be upright and gas only. 

 

WARNING: Do not allow any liquid freon on the lo side. This is just as bad as allowing water to enter the intake of an engine it will hydro-lock the compressor and could possibly explode!

[dripley]

Thanks guys, @Haggar and @Mopar1973Man. Those gauges fuzzle my brain sometimes. But I have managed not add anything to the high pressure side of mine or the wifes car. Matter fact I rebuilt both hers and mine. Mine the summer before last and her Saturn last summer. Both have held up pretty well except for mine warming a little. Mine by far was the easiest and cheapest. Her little car cost almost twice as much as mine fo the parts. And getting to some of the parts was no fun.