AC help needed please

Where do you get R152a?

Walmart or anywhere. It's keyboard duster. Pretty cheap too.

Bruno2 wrote

Walmart or anywhere. It's keyboard duster. Pretty cheap too.

Interesting. How do you service it? Attach a hose to it?

At one time keyboard duster was R12. Of course they deemed that unsafe for the environment. Then they had the perfect keyboard duster replacement R134A. Then the EPA witch hunt turned their sights on it so they came up with R152A.

Which is a great refrigerant. It runs lower pressures in your system so it puts less stress on your compressor.

I am running it in my 2012 Ram 2500. It will put 39° air out of the vents when it's 96° outside.

I took a 90 minute roadtrip on the hwy last weekend . It was almost 100°. I couldn't run the system on high the whole time it became unbearable. I have been runni g it for about 4 years now with no problems.

Thank you! Man that is a neat tool!

I have not touched the truck for a week, took it to work today and at 2am the drive with 260 air was not bad.
Even on the way home the 260 air was not bad till it stopped working, no 60 only the 2 and using 245 when I did the trash. (2 windows down and do 60 mph)

There is a Cars & Coffee the car club is going to in the morning till about noon if the temp & weather is not to bad.
Then there is a evening cruise the club also wants to go to and it is next door to a good burger joint so the wife & I will go to the cruise & a burger.

So I dont think I will have time Saturday to look at this unless I go out later when cooler but I have been up since 12am for work so looks like Sunday.

My question:
If I cant get the system to take a charge I am looking to replace the compressor, Evap coil & dryer w/ orifice valve.
Can the evap coil be changed out without pulling the dash apart?
Can you undo the HVAC box in the engine bay to swap the coil?

Coil was from parts truck and was flushed and was clean.
Compressor was a junk yard unit and did work when first installed but always made noise.
The dryer, hoses & valve were all new when I first got the system working.
I figured if I have the system open for the compressor, got a feeling that is why it is not working, I might as well change the coil.

I also heard a tin can popping by the HVAC box area when I first started to pull a vacuum.
Beside the dryer the coil is the only other thing in that area.

Thanks for any help you can give
Dave ----

Bruno2 wrote

At one time keyboard duster was R12. Of course they deemed that unsafe for the environment. Then they had the perfect keyboard duster replacement R134A. Then the EPA witch hunt turned their sights on it so they came up with R152A.

Which is a great refrigerant. It runs lower pressures in your system so it puts less stress on your compressor.

I am running it in my 2012 Ram 2500. It will put 39° air out of the vents when it's 96° outside.

I took a 90 minute roadtrip on the hwy last weekend . It was almost 100°. I couldn't run the system on high the whole time it became unbearable. I have been runni g it for about 4 years now with no problems.

So I'm really curious about this! If this is such a great refrigerant and does not harm the environment, why is it not available for use in our vehicles? Found this on Youtube. By chance is this you?

 

Ok I added what was left of the 2 cans I started by soaking them in hot water and with the everything off I could hear the first can push in.
The 2nd can I had the motor running I also added a 3rd full can and at least the compressor stays running.

But it is not blowing cold just some what cooler air.
The low side is 30 psi the high side 155 psi.
If I bring the RPM up only the low side drops to about 25 psi.

I feel between the noise the compressor is making and the PSI not really changing other then when I add a can of Freon the compressor is not working.
I do not see either needle jumping around as someone posted if the compressor is / was going bad.
It just is not building anything on the high side like it did when I first got the system working.

So with that said I ordered a compressor less clutch as the one I have is only a year old and most of the compressors listed 1 wire hook up and mine is 2.
I also ordered the evap coil & dryer and already have a new orifice valve.

I will also go through and replace all the o-rings again just to be sure I have no leaks and will pull a vacuum for hours to make sure it pulls a deep vacuum and that it holds .... again I dont want any leaks!
Dave ----

Bruno2 wrote

I prefer the orange orifice tube. I can make them blow cold with any of them.

Another thing people don't like to consider because it's not that common is R152A is more of a direct replacement for R12 than R134A is.

When swapping R12 to R152A use a multiplier of .55 for the charge.

When saapping R134A to R152A use a multiier of .65 .

So let's say the system calls for 10oz of R134A . 10 X .65 =6.5 oz is your R152A charge.

I think R134A is closer to R12 than R152A.

You said to switch to R152A from R12 you charge to 55% of the R12 Capacity.  With R134A you charge to 75% - 80% of the R12 Capacity.

My 78 Mercury I run it at almost 90% capacity of R134A because its not just an expansion valve system but it also has a STV which requires a higher initial pressure to get cold air.  At 90% capacity in this instance I was able to see interior cabin temperatures on a cloudy day drop into the mid 40s.

My 82 F150 I dont know what I run it at as there is no spec for dealer AC capacity, but I charge it up a bit on the higher side when using the temperature charts for mobile AC systems and even on a 100* day I steadily get 58* out of the driver side vent.

At work I vary between 75% and 80% based off what the pressures are reading.  Some I can squeeze up to 80% due to an excellent cooling system that can keep the head pressure down and other times its 75% cause 80% would result in a 300+ psi head pressure.

No, that's not me. This is a decent video though. I did a ton of research on it before I did it. I still can't find info on whatbthe guages should actually be reading at what ambient temperature. I even called the manufacturer to speak with an engineer about it and they couldn't tell me.

A lot of the videos show people way over charging their systems. I have a write up about it on tnis forum somewhere. Another great thing about is that you can use just about any AC oil with it. It isn't finicky about lubrication.

I think the reason it is supposed to be closer to R12 has to do with mecule size and oil compatibility.  Also something about coil size. Like R12 doesnt require as much surface area to exchange heat to run efficiently or vise versa. I don't recall. I did a ton of research on it before I started playing with it. There is a lot of info out there on the topic. Probably a lot more now as time has marched on since then. 134 doesn't work as well in an R12 system. There are a lot more differences between the entire systems besides the.oil type and expansion valve size.

Everything has to do with politics and.patents in the US. One the patents on refrigerants start to expire the EPA coincidentally deems them unsafe for the environment.

152A has been used in automotive applications for awhile in Europe.

I too share the same "opinion" about politics and patents. I have been an hvac tech since the early 90s and dealt with the whole thing through r12/r134a as well as r22/ r410a and all of the so called "drop in " replacements.
trying to explain to mrs johnson why last year's cleaning service and top off for $125 was now a recover, flush, treat, change out the drier then replace with the new "approved" refrigerant and now is $1500 was no fun. that's when we start the ten year warranty sales pitch. what I hated was that I had a considerable number of customers who were with me longer than most warranty's. and I built that business on keeping machines running not just selling the latest thing. it was great for referrals too.

Good points, gentlemen. Thanks for the insight. I work in medical and see it there too.

Before I retired from NNS we had some Freon leak detectors the Navy has through out their ships in any confined location where a leak could occur. We had to calibrate (more certify their accuracy) them before they could be installed.

The Navy had just started using a new refrigerant (and I do not remember the number now) that could be both a refrigerant and a fire suppressant. Our Metrologist (calibration specialist) was a retired USAF bootstrap Major and he was good at his job which involved a lot of record keeping. When these units came up, all he was going by was the chemical formula which on most fluids or gasses is what you need. Organic (hydrocarbon) compounds, you also frequently need the structural formula (where the hydrogen and other atoms attach to the carbon string).

He and the technician and chemist trying to calibrate these were tearing their hair out. This lowly former USMC Staff Sergeant, googled the refrigerant and found 4 I think different structures and one was completely different in characteristics. Guess which one the Navy was using? When I showed Greg (the metrologist) and Gary (our supervisor) what I found, Greg's comment was "I guess I should have paid more attention in organic chemistry". Once a pair calibration standards were ordered and received, the alarms calibrated perfectly.

I have been checking other forums for this issue, still going forward on replacing the evap coil, compressor & dryer.

What I have seen when using the adapters from R12 fittings on the truck to the 134a is to remove the valve core from the truck side low side as the low side adapter has a core valve.
You dont do this on the high side as the high side adapter dose not have a core valve.

Is this true?
I dont remember having any issues the last time I charged the system and I installed them.
I also did not see anything that came with the adapters.
So what is the deal leave the core valve or remove it from the truck side?

I got the parts from Rock Auto but the dryer was wrong.
The box looked to small and when open it is a kit to rebuild a dryer?
Number on the box is 83200 and the packing list has 33200.
Dont know if will reach out to RA or not but I ordered a dryer local and should be in tomorrow.
Dave ----

I have been ordering through RA for many years now and have the refrigerator magnets to prove it.
unfortunately, I have had incorrect parts sent to me a couple times lately and still have not received a pair of shocks that they insist was delivered. but there is no way of calling or contacting anyone about it that I have been able to do. it's enough that I am using my local parts store more since I know that I can walk in or even call "chad" and get someone working on it. Now I just moved so I'm referring to the local oreillys near the shop here in NC south of me not my home shop. but I had similar in nashville also. Good help is hard to find they say. I always answered, " no its impossible".  

The dryer I think was $25 so not to big a deal and been thinking of not even wasting my time.
Now the same part from O'Reilly was $45 but should be at the store when they open and I ordered it think was 2pm cant really beat that if you want to do the job over the weekend.

Dont know if I will go to a cruse Saturday yet or not, they say its going to be the hottest day yet, so dont want to pull the truck apart and then want to go and cant?


So any word on pulling the shrader valve on the low side be for installing the adapter or leave it?

Also how hard to R&R the evap coil?
Looks not to bad as it looks like it comes out the engine bay side.
Looks like just remove half of the HVAC box and it pops out?
Dave ----

Yes, the evap comes out the engine side of the HVAC box.  Not too bad at all.

Good luck, Dave!

Edit: I don't know about the valve, but I can's see why you need two back-to-back.