That makes total sense. I have been struggling with this for some time myself and I opened a post on this.
You have it right Jen, $200 + for R12 cans (16) vs $59 shipped for a case of 12 R134a, it is a no brainier.
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My Hawaiian HJ60 Refresh, Maintenance and Good Times
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That makes total sense. I have been struggling with this for some time myself and I opened a post on this.
You have it right Jen, $200 + for R12 cans (16) vs $59 shipped for a case of 12 R134a, it is a no brainier.
Can you explain a little more on what you meant by "flush your piping with nitrogen during the vacuum phase". What exactly is this process? Why is it important? Did you do this, or did you have an AC shop do it for you? Thanks!
So after you've got everything hooked and sealed to the best of your knowledge, you'll hook up the vacuum pump, high side or low side, doesn't really matter. If you have an A/c vacuum gauge (not the same as your High Side, Low Side Gauge Manifolds), you'll want to draw your vacuum to at least 500 microns, the lower the better. Once your there it should hold at that scale without the vacuum pump on. If it doesn't and the gauge rises, then you have a leak somewhere and the hunt begins. But say you get it to hold! Awesome! So while your putting a vacuum on it, you'll hook up nitrogen to the opposite side that you are drawing vacuum from. With the pump running, your going open up the nitrogen bottle for a few seconds then close. The nitrogen will then sweep through your system to help remove any air and or loose particles to be captured by the oil in your vacuum pump. The biggest killer to the lifespan of an A/C system is AIR! I will turn your refrigerant acidic and slowly eat your system from the inside out, as well as lost efficiency. You'll do this nitrogen sweep (typically called a triple sweep)... 3 times! Ha! After the third, you'll let the pump do its job until you hit the 500 microns. At this point remove the pump and charge from there.
I will be doing this on my own, but to be fair, I went to school for A/C quite some years ago (and still rusty in a lot of areas) and I'm borrowing all the equipment to do this from work. Others here may have a simpler solution, but this is generally an industry standard.
BTW Sorry I never got back to you guys about being on Oahu, decided not to ship the truck over do to cost and my lack of free time over there. I'm back on the Big Island now for a couple weeks to get some family time in, before I head back over to finish the repairs on my ship. Sounds like I'll be there on Oahu till the end of June. So maybe when I get back over there, I can lend a hand.
Mudders, please chime in if I've missed something or explained it horribly! lol!
Perhaps for houses and commercial buildings you do a nitrogen sweep where you are brazing copper pipes, but for automotive you don't. If you go to a shop and ask to have a nitrogen sweep they will think you are crazy. In a automotive system where major components have been replaced you simply pull a vacuum for about 45 minutes. Then fill with r134 and enjoy. You could just take it to a Toyota dealer and have this done. Just make sure that you have put the appropriate amount of ac oil in each component before you close the system. Especially the dryer and compressor. The repair manual should have a chart for how much oil each part takes. As far as the ac hoses and pipes that you use that aren't new, spray some brake cleaner in them, blow out with compressed air, and install. That's really only if u kept those pieces in a dirty environment while in storage. Don't install the dryer until last and your ready to closeup the system. If the dryer is left open to atmosphere it will be ruined.
How long is too long for the dryer to be exposed open to the atmosphere? It's brand new and installed, but a leak was found on the hose off the compressor. So the system was opened up for a day. Do I need to replace the new dryer now? We had in on a vacuum overnight to try and remove any air/moisture.
I'm not really sure. I imagine it's probably fine.
Your right, the method I'm talking about is used in the commercial, refrigeration, freezers, and all things cold. I submit that i was never really trained on the automotive side, but a/c is a/c! Don't understand the methodology of just pulling a vacuum for 45 mins without knowing if your vacuum is holding or at what micron level... Find the problem before you keep having to recharge your system constantly...just because you can get away with a quick fix, doesn't mean its the right way! just my 2! But hey, I may have a bit of OCD that is speaking for me!
Part of it is that you are only talking about 1 lb of refrigerant which at my cost is less than $4. You also have a dryer that takes care of the moisture if there is any left over. There is not a big problem with automotive systems corroding from the inside out. I like the idea but its just not practiced in the smaller systems.
Yes it is a good idea after you pull vacuum for a while to shut the machine off and watch the gauges for a while to see if the vacuum holds I think, especially when you've performed major work. I usually will let it sit for about 15 minutes and see if it's held. Then I fill the system. I guess I left that detail out.
Thanks, really appreciate all the advice. We have been plagued by leaks in the AC system, and has been frustrating trying to track them all down....even with the UV dye and black light. The system holds vacuum for 15 mins, but when left for an hour, the Hi side shows a drop in vacuum. The Low side holds a strong vacuum, so we suspect there is a very small leak somewhere on the Hi side?!? The investigation continues, but frustration is high and morale is low on this AC system fix....so it may need to go to a shop if we can't figure it out today.
Well doing such major a.c. work, if it's your first time can be a slow process. I have done this a lot, and once you do it a few times you get good at getting every connection leak free the first try. Anyway, try pulling a vacuum from the low side only and monitor it that way. It could be you have a leak in your gauge or something on the high side. The nice thing about this part of the process is your done buying parts. A way to check for leaks is to charge the system, and spray all the connections down with a spray bottle filled with water and dish soap. If their is a decent leak you should see bubbles flowing from the leak, don't pay attention to static bubbles from the soap. Their are probably youtube vids on this method to help you out if you search. Another thing you can do is buy a r134a leak detector. It has a wand on the end of it, and you move the end of the wand all around the connections and it will beep quickly if it finds a leak. Using the dye and uv light method is only really used if you charge the system and drive it around and use it for a few weeks, it won't work really if you just charge it and look right away.
I'm a little confused. Will pulling a vacuum from just the low side tell me if the entire system is sealed? Because the manifold gauges (rented gauges from autozone) show that the lo side holds a vacuum but the hi side does not and slowly leaks out. Even overnight, the low side showed it holding a strong vacuum, while the hi side had lost it. Are the lo side and hi side separate sealed systems?
Yes pulling a vacuum from just the low side will tell u if it's sealed. Disconnect the high side gauge hose from the compressor. Then pull vacuum. Basically the compressor compresses the refrigerant, sends that to the expansion valve, the valve reduces the pressure and refrigerant goes to the evaporator then back to the compressor and it's compressed again. But when the system is off or static everything settles and their is no pressure difference in the whole system. Keep in mind when u do add r134a to the system, it is a different amount than u would r12 fyi. Youtube will have vids to show how it works. But ya just vacuum with low side, disconnect the high side gauge hose from the compressor and see if vacuum holds
Just to add when system is empty and open to atmosphere the drier is exposed to moisture even if you are in the middle of Arizona during summer. I would just vacuum it overnight on both sides (High/Low) the expansion valve is close reason why one side can leak and not the other. You guys do AWESOME work IMO.
Thanks for the advice. The vaccum was put on hi and low side last night for an hour and everything looked to be holding. But ran it all night last night on the low side only. Ran for approximately 9 hours and now seeing if it will hold the strong vacuum (27.5 Hg) for a few hours today. If it does, we will attempt to fill it with r134 later this afternoon. Hopefully, we will have cold AC filling the 60 by this evening!!!
In a real world reading 29.8 in/hg is good enough which is about 99.9% vacuum and a dead accurate gauge. Since your gauge is rented it's most likely out of calibration.
I've gotten a little behind on posting work we have completed, mostly due to dealing with AC install setbacks. But a lot went into getting everything set up for the AC.
To get the new denso condenser installed, some minor tweaking had to be done to make the fj60 condenser fit into my hj60.
The AC hose coming off the compressor to the condenser needed to be reshaped to fit the new angle of the condenser fitting.
Also needed to address some issues with the evaporator box under the dash. The one we bought had some cracks down in the bottom near the drain hole. Since we didn't want AC water dripping on our new interior, we epoxied over the cracks on both sides of the box. All sealed up!
Then the crumbling weatherstripping on the evap box needed some replacing. Used adhesive backed rubber sponge window weatherstripping to replace the old stuff. It's pretty dense and just the right size for a nice tight fit.
To get the new denso condenser installed, some minor tweaking had to be done to make the fj60 condenser fit into my hj60.
The AC hose coming off the compressor to the condenser needed to be reshaped to fit the new angle of the condenser fitting.
Also needed to address some issues with the evaporator box under the dash. The one we bought had some cracks down in the bottom near the drain hole. Since we didn't want AC water dripping on our new interior, we epoxied over the cracks on both sides of the box. All sealed up!
Then the crumbling weatherstripping on the evap box needed some replacing. Used adhesive backed rubber sponge window weatherstripping to replace the old stuff. It's pretty dense and just the right size for a nice tight fit.
Then it was on to rebuilding the evaporator box contents. A new denso evaporator core, and new denso expansion valve and 24v pressure switch were put in along with all new r134 compatible o-rings.
All put together and ready to be boxed up.
With the evaporator box complete and installed under the dash, we hooked up the hoses and lastly installed new dryer with r134 compatible o-rings. With the AC system all hooked up, it was time to get some gauges on it. (Edit: multiple leaks found and fixed and one new compressor later, the system finally held a vaccum)
Here's me learning way more then I ever wanted or cared to know about AC systems.....don't let the smile fool you, I will be sooo glad if we never have to deal with the AC system ever again.
All put together and ready to be boxed up.
With the evaporator box complete and installed under the dash, we hooked up the hoses and lastly installed new dryer with r134 compatible o-rings. With the AC system all hooked up, it was time to get some gauges on it. (Edit: multiple leaks found and fixed and one new compressor later, the system finally held a vaccum)
Here's me learning way more then I ever wanted or cared to know about AC systems.....don't let the smile fool you, I will be sooo glad if we never have to deal with the AC system ever again.
AC Looking great, FYI that weatherstripping I have used before and is basically the same stuff vintage air supplies with their Domestic kits. So it will work just fine.
That's an awesome job Jen! I honestly don't think there is a shop out there that could have done better job with your ac install.
