AC Rebuilding Quesion?

[old55pete]

When you put in the freon, was the can right side up or upside down( valve pointed to the ground )? If you shake the cans, can you still feel liqued in them?

When you installed the orface tube, did you put the colored side in first so the white side was sticking out just a little?
 

[FuzzFace2]

I was flipping the can back n forth.
The first can had a little left I think because the motor & pump were not running and felt empty when I undid it.
The next can I also flipped motor & pump running and it was empty.
3rd can flipped motor & pump running and had a little less than the first can so I would say 2 and 3/4 cans went in.
I did forget to close a valve when removing a hose but a vary small bit came out.

I questioned the valve.  when I went to install it and I found it would only go in one way. I also made sure it was in all the way.
At 1 point when filling I saw frost where the valve is but after more freon went in no more frost.
Thanks
Dave ----

[FuzzFace2]

85lebaront2 wrote

What you found on the switch is not surprising, the switch screws on to a port that is essentially an R12 fitting for the gauges. The pressure temperature curves for R12 and R134 coincide at 60° F, below that R134 pressures are lower, above that they are higher. Since the port the switch goes on didn't change, and the switch is adjustable it stands to reason that many sources will sell the same switch and list it for both. Here is a temp pressure chart that may help:


The switch has a pair of 1/4" wide (I think) male flat blade pins, the plug has the female portion. I made a pair of around 2" long, enough to allow the plug to be moved far enough that I could get a flat blade screwdriver into the adjusting screw. You want the pressure about 29 - 30 psi so the evaporator temperature will be near 34° F to keep it from freezing over.

This was how I set the switches on Darth and the Lincoln. Both worked quite well, Darth now has a 1996 HVAC system with all the improvements. FYI, it is physically a bolt in as far as the underhood and inside casing are concerned, but the wiring routing changed and the inside has an added "demister" portion to put dried air on the wing vents when using the defroster either as a mix or full.

Question on the chart.
The psi for a given temp I take it outside air temp and is it the high or low side psi?
If high and you can't read the high side what can you do?
Thanks
Dave ----

[Gary Lewis]

This chart is from RechargeAC.com, and it doesn't jive with Bill's chart.  Nor do many of the other charts I've looked at.

Bill's chart says that whatever pressure that is should be 124 psi at 100 degrees ambient.  This one says that the the low pressure should be 50 - 55 psi and the high pressure should be 315 - 325 psi at 100 degrees.  That's a big difference.

But I will say that having recently checked the pressures on the Subie, which uses R134a, the pressures pretty well matched this chart.

[85lebaront2]

My chart is the static pressure and is mainly used to get the low side to the desired temperature. High side will vary with ambient temperature and airflow over the condenser.

[Gary Lewis]

Ahhhh!  Dawn!  Marblehead!

That makes sense.

[grumpin]

Use a bucket of warm, not hot, water to help get all the refrigerant out of those cans.

That chart looks like the one I have. I’ve worked with R12 and R134. I didn’t like it when they made R12 difficult to get. Mainly because it was new and R12 worked. R134 works, but to me it’s not as stable as R12.

[FuzzFace2]

Static  I would have never guess that.
When I hook the gauges back up I will check to see where mine compares.

Now the chart that Gary posted of 50-55 on the low side I can say I am below that so fingers crossed a little more Freon and I will be frozen inside.

grumpin wrote

Use a bucket of warm, not hot, water to help get all the refrigerant out of those cans.

That chart looks like the one I have. I’ve worked with R12 and R134. I didn’t like it when they made R12 difficult to get. Mainly because it was new and R12 worked. R134 works, but to me it’s not as stable as R12.

The hot water did cross my mind but I don't think there is that much left in either can to even fuss with but I will recheck.

I did pick up 2 more cans of Freon and a vacuum check valve.
When climbing a hill or heavy on the gas the AC vent goes to defrost. I knew the check valve was bad not I have to fix it.

Thanks guys for all the help.
Dave ----

[FuzzFace2]

WE ARE CHILLING!
First I have to say thank you for all the help to get this working.

All readings are on the low side of system as I don't have the adaptor for the high side.

When I first checked static PSI it was 88 PSI @ 90*F and by the chart should be up around 104 - 114 PSI
When running, fan on high, RPM @ idle, large fan in front of condenser I had like 45 PSI, chart said 50 - 55 PSI.

I used a bucket of hot water on the cans and even emptied the 2 that had a little still in them.
The 3 first can did not bring it up to the 50 - 55 PSI so added a 4th and still not so a 5th went in.
That got it up to 58 PSI at idle and at about 2000 RPM came down to the 50 - 55 PSI reading.
Also when you unscrew the low side hose, some Freon comes out so I would say I am at 55 PSI.

So 5 - 12oz cans of Freon & 8oz to 10oz of Ester oil was needed to get my system working.

Oh an not too soon as the front fan, front / rear system, in the Durango stopped working this morning when I got in it at 1am to go to work.
I have replace the resister for the fan like 3 time & the pig tail to it once because it melted but the fan always worked on high. I hope the pig tail melted and why the fan does not work. I don't know where the fan motor is and what it would take to replace it?

Thanks again
Dave G

[Gary Lewis]

Congrat's!!!  

So, you'd stopped at ~2 cans and it took 5?  I'll bet that made a huge difference.  

[FuzzFace2]

Gary Lewis wrote

Congrat's!!!  

So, you'd stopped at ~2 cans and it took 5?  I'll bet that made a huge difference.  

I stopped at 3 because that was all the cans I bought the first round and because I thought I seen it posted 2.5 cans is what it took.

After messing with the system and understanding how it all works then seeing the charts it gave me something to go by.
That is why I did the 2.5 cans of freon as that is what I had to go by.
Dave ----

[FuzzFace2]

Update:
I picked up a temp probe to measure the temp out of the duct.
This was taken fan on high, MAX setting in vent to the right when sitting in the drivers seat.

OAT was 90*f
Driving between 45 & 48 MPH in over drive
RPM 1200 to 1300
The lowest temp I got was 51.6 as I had some lights to stop for where the temp went up to 53.7

IIRC the chart had a temp of 50 - 55 with OAT of 90*f
A spread of 40* I think is pretty good.
Dave ----

[Gary Lewis]

Yep, that's pretty good.    But I'll bet it is colder on the vents on the passenger's side as they are closer to the evap.

[FuzzFace2]

Gary Lewis wrote

Yep, that's pretty good.    But I'll bet it is colder on the vents on the passenger's side as they are closer to the evap.

But harder to see the numbers on the probe with my good eyes
I will see if I can get a reading from over there.
Dave ----

[old55pete]

This is mine at an idle, 101 outside, 50% humidity with 36 ounces of R134 and an ounce and a half of pag 150 oil. High pressure guage at 250, low pressure guage at 35 psi, no fan blowing into the grill, just the engine fan pulling air through the condinser and radiator.