How much freon after vaccuming?

How much freon after vaccuming?

Postby dnwong [OP] » May 28th 2015, 10:02pm

I have front A/C only.

I vacuumed the system and verified the after the new compressor, accumulator and orifice installed that I had no leaks.

I put in 2 (based on the specs) cans and the pressures are 50/150 on the manifold.

However, my inside vent temp only gets to about 60degrees.

Now that the weather is getting hotter, the A/C system does not seem to be cool enough.

Should I add more freon?
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Re: How much freon after vaccuming?

Postby Lumpy » May 28th 2015, 10:27pm

I think it's hard to go by gauges when the weather is warm, hot or blistering (as it always is here in Phoenix). The way I do it is to charge with refrigerant till the compressor stays on by itself, then just a tiny bit more. That seems to work the coolest for me. I've tried charging to recommended pressures and didn't have good results.

Our vans are hollow, big, bricks. When it's 100 deg outside, it's 110+ inside. Asking the A/C to bring that down much is asking a lot.


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Re: How much freon after vaccuming?

Postby scoundrel2u » May 28th 2015, 10:46pm

if i remember correctly... 2 cans is more than enough. In fact, it may be slightly over charged.
For every ounce you overcharge your system, efficiency takes a huge hit.
I use the enviro-safe refrigerant, and 2 cans is overcharged by one ounce. But need not worry...
most systems leak at least 5% of the refrigerant annually. lol.
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Re: How much freon after vaccuming?

Postby dnwong [OP] » May 28th 2015, 11:01pm

To me, the system is not as cold as when the original system from the factory. Should I bleed some out. Also, I could have too much oil in the system. I added 3 oz to the compressor. I read that the compressors come with oil in it.
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Re: How much freon after vaccuming?

Postby scoundrel2u » May 28th 2015, 11:52pm

sometimes a big risk to add oil or not ? If you add too much oil, you could hydro lock the compressor... since that didn't happen... it's probably just fine.

My system acted the same way when i first vacuumed the system and recharged it. i ran it that way until my case of refrigerant cans arrived. Probably a clogged orfice.

I evacuated the system again. This time, i pulled a vacuum for at least a half hour to an hour, twice. This lowers the pressure inside your system and boils off any moisture and cleans the inside. The compressor oil doesn't usually boil away (don't add more oil). doing it a couple times helps force the crap out of the orfices ?

I recharged the system while under a vacuum with the recommended amount of refrigerant. It works great now. The second time is a charm.

As lumpy said, it's better to under charge a system.
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Re: How much freon after vaccuming?

Postby redfury » May 29th 2015, 12:22am

Yeah, I'm thinking you are probably just a bit overcharged, and you want to get away from that condition ASAP as you risk getting liquid refrigerant back to the compressor.

I over oiled my system...that I know for sure. My pressure spiked to 450 PSI and blew oil out of the seals on top of the compressor and made a mess out of my engine...green oil everywhere. I have rear Air and put in about 6 oz. I'm going to drain the compressor of all of its oil and try over. There is enough oil in the system right now to keep the compressor happy. If it makes noise, I can always add oil through the charge port. My system wouldn't cool down like it should either until I got the right amount in it. You should see the muffler off the accumulator/drier sweat and it should feel really cold. I use a non contact laser thermometer to check the charge running into the system now.
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Re: How much freon after vaccuming?

Postby Lumpy » May 29th 2015, 7:05pm

dnwong wrote:To me, the system is not as cold as when the original system from the factory.



We don't know what year your van is...

Was the original refrig R-12 and you (or someone) has converted to R-134a?


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Re: How much freon after vaccuming?

Postby dnwong [OP] » May 29th 2015, 8:39pm

Lumpy wrote:
dnwong wrote:To me, the system is not as cold as when the original system from the factory.



We don't know what year your van is...

Was the original refrig R-12 and you (or someone) has converted to R-134a?


Lump

It is a 95 Astro Converson w/front A/C only. r134a. Ran really cold till the clutch died then messed up the bearings. The folks who replaced the compressor 5 years ago probably did not flush the system, when I replace the compressor recently, found metal in the orifice.
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Re: How much freon after vaccuming?

Postby mt94ss » June 10th 2015, 6:43am

The amount of refrigerant that you need is written on the tag on the A/C housing on the firewall. Front A/C only is 2 lbs 4 oz, or 36 oz (3-12 oz cans).
IMG_4204.JPG


I just redid my whole system. Used the gauge and vacuum from Harbor Freight. Found out that my system had a leak so I just replaced everything (pump, dryer, tube, and seals) from Rockauto for less than $200. Hardest part to replace was the compressor but it did come pre-oiled for front A/C only, which worked perfect for me. 3 cans of r134a and I was back in cold A/C. I added mine with a single can filler (the cheap one) not under vacuum, while the engine was running. You can tell when the refrigerant level is getting close as the pump cycles less and less until it is just on. Replaced every O-ring in the system too with ones from the kit Took about 4 hours start to finish. The one thing that I had to pull of my old compressor was a sensor/switch from the back of the unit that the replacement unit didn't have, it was plugged instead. I just removed the cir-clip and swapped it for the sensor/switch.

Glad that I got it fixed as it has been really hot for here, above 90* but the A/C blows cold.

Good luck!

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