a/c install do you need a negitive vac
 

so i've just pieced my a/c system together to go back into my eg. my question is that every post i've seen says you need to pull a negative vac on the system to recharge it.

isn't this only if you're trying to evacuate the old refrigerant??

also can you flush out the compressor i know it will need the oil replaced... i'm going to be using a a/c flush on the lines, and thru the system. change out the drier, and A/C TXV (TH3ERMAL EXPANSION VALVE).


Other than that it should be straight forward right?

Re: a/c install do you need a negitive vac
 

On a A/C machine, the vacuum is what pulls the refridgerant into the system. Makes sure that no air pockets are in the system.

Basically, you evac, hold vacuum for at least 5 minutes, then recharge.

But since you are replacing parts, you pull vacuum for 5 minutes, and then let the vacuum pull the refridgerant and oil into the system.


Holding the vaccum for atleast 5 minutes just makes sure you don't have any leaks. It would be sad to put all the money into it, and find out you didn't get a fitting tight or something and all the refridgerant leaks out.

Re: a/c install do you need a negitive vac
 

Yes a vacuum is needed, I would run a vacuum pump for at least 1hr on any A/C system that has been "open", this will insure any moisture in the system is boiled off.

I flush out compressors all the time, pour flush into the suction side, rotate clutch clockwise as you drain the flush, repeat a few times, and make sure all flush is drained when finished.

When reinstalling put 2oz of C4 oil in compressor and split the remaining oil charge, [Ester oil] between the compressor and the filter/dryer, assemble, a nitrogen pressure test @ 250PSI should be done at this time, the longer the better, but at least 1 hr.

If pressure holds, 1hr on a vacuum pump, close valves on gauge and let sit for 5min, if vacuum holds recharge system. 94

Re: a/c install do you need a negitive vac
 

more or less if i have to go out and buy a vac pump / compressor and gauges would it be more ideal to take it to a shop?

Re: a/c install do you need a negitive vac
 

In the long run, it will be cheaper to take it to a shop, you would need a set of gauges, a bottle of nitrogen W/regulator, a vacuum pump and recharge cylinder or a R134A Computerized Freon Recycler and unless you can rent the equipment or are going into the A/C business, it's not worth it...

A gauge set will cost at least $50, [cheap ones].

Nitrogen is cheap, $35 for a tank, $300-$500 deposit on tank.

A vacuum pump will be $50, [cheap one].

A recharge cylinder will be $50, [cheap one].

A combination vacuum/recharge unit will be $300-$3000.

A tank of R134A will set you back $250, [30lb tank].

A leak detector will be $150, [cheap one].

As you can see, if you can't rent what you need, and depending on rental price a shop may be cheaper.

We charge $20 for a nitrogen pressure test.
$120 for a recharge.
$2 an oz for R134A

The above would include at least .5hr on nitrogen pressure test, 1hr on a vacuum pump, 10min. vacuum leak test and a refrigerant leak test.

$15 more will get an oz of UV dye for future leak detection.

The above should be about the same at any A/C shop. 94

Re: a/c install do you need a negitive vac
 

1 last question and probably a good question. Since I will be changing all my own parts as soon as I put everything together I should have no issues with taking it to a shop and getting the system charged. I know you would probably want to put the system together because of possible contaminates f**cking up your gauges.



So i'll slap everything together find a shop and have them do the refill. The Ester oil goes into compressor with out needing to be pressurized... Just using a measuring cup or what not and fill it to specs. I have to figure out which compressor i have since it's not labeled correctly. When the inital system with in my 95 Civic, the lines had the old style R12 connectors.. So i'm guessing they pieced sh** before me at the local junk yard.

Re: a/c install do you need a negitive vac
 

sorry to hyjack the thread but what is a good vac pump to get that,s not to expensive cause im always filling up ac systems for me and friends and i rather have the right stuff and do it right or rightish lol

i already have the gauge set, need vac pump but i ussually change all the rubber seals and use oil to hookem back up so do i still need the nitrogen to test

could i just get away with the vaccum test and just charge the system with freon

Re: a/c install do you need a negitive vac
 

http://www.harborfreight.com/catalog...?q=vacuum+pump

harbor has a cheap one that you use with your compressor, but i heard you really need a compressor to keep up. **on sale for 12.99**

they also have a more commercial type of pump which is electric for 100 bucks. and with the 20% coupon you can get a great deal i would think....

manifold gauges for 50.00
http://www.harborfreight.com/catalog...result?q=a%2Fc

Re: a/c install do you need a negitive vac
 

Any shop will "ID" the system, it will tell them if there are any contaminants, [hydrocarbons] in the system, if there is most shops will not touch it any farther.

If your car is a 95 and the A/C system is from a 95 then both will be R134A,

All cars from 94-up are R134A, the compressor for your car, [95 Civic] should be a Sanden/Sankyo TRS090 for both the 1.5 and 1.6 engines.94

Re: a/c install do you need a negitive vac
 

is there any markings i can see on the compressor? i will take a photo of mine tomorrow as i don't see anything marked on it.

also the hose setup that was on the car when i bought it had the old style R12 schrader valves.

Re: a/c install do you need a negitive vac
 

bump

Re: a/c install do you need a negitive vac
 

Take a few pic from all angles.

If you had R12 service ports, either the car is not a 95 or the A/C system was installed after the fact.94

Re: a/c install do you need a negitive vac
 

FCM: I know the car was hit in the front and the radiator support was replaced. I think they replaced the system with an old system out of a pre-94. This is my theory... So over the weekend i went down and got all new lines from a R134A system, but will still use the compressor. I'll take pictures when i get home. Actually the woman is at home today maybe i can get her to take pictures of the compressor while it sits on my work bench.

Re: a/c install do you need a negitive vac
 

That may be a problem, hose assemblies can be diff. form one compressor to another.

This may help... http://www.4s.com/Online%20Catalogs-...g/Content.aspx

Select your car, select complete A/C repair, hold curser over blue part numper for a pic of part, if you click on the part number you will get more info and if you place curser on pic in the more infoe window you get a bigger pic. 94

Re: a/c install do you need a negitive vac
 

Pictures of the compressor. No markings at all.



http://www.n0cturnal-labs.org/junk/p...r/SDC10064.JPG

http://www.n0cturnal-labs.org/junk/p...r/SDC10065.JPG

http://www.n0cturnal-labs.org/junk/p...r/SDC10066.JPG

http://www.n0cturnal-labs.org/junk/p...r/SDC10067.JPG


http://www.n0cturnal-labs.org/junk/p...r/SDC10068.JPG

Re: a/c install do you need a negitive vac
 

when i meant not to expensive i meant between 100-200 dollar range and commercial

imma check out the 139.00 harbor freight unit

so what you think fcm

Re: a/c install do you need a negitive vac
 

That is the correct compressor for a 95 Civic, it was also found on 94-00 Civics, 94-95 DelSol and 97-01 CVRs.

Got pix of service ports? 94

Re: a/c install do you need a negitive vac
 

when i get home i'll take some pics.

Re: a/c install do you need a negitive vac
 

when flushing the hardlines is there an alternative to using "A/C Flush Fluid." I was thinking of denatured alcohol, just a thought.

Re: a/c install do you need a negitive vac
 

No, A/C flush only. 94

Re: a/c install do you need a negitive vac
 

http://ecx.images-amazon.com/images/...500_AA300_.jpg

so ended up picking this stuff at autozone, it's compressed and did most of my lines and compressor with it. i will have to buy another can for the condenser/radiator and the inside cab a/c stuff. blew air through the system afterwards. more to come...

also won't most a/c shop do a flush when i take the system in to get charged?

Re: a/c install do you need a negitive vac
 

a good shop most half azz the work

Re: a/c install do you need a negitive vac
 

You should not use air to blow out the lines, the flush "propellant" is most likely nitrogen, it is what we use with our bulk flush, air is full of moisture and that is not good for the system. 94

Re: a/c install do you need a negitive vac
 

so what's the best way to get the rest of the flush out of the system? all i have access to is a compressor..... also what would be the best way to flush out the EVAP since it's all coiled up. I know the flush would be pretty hard to get out of the line.

This flush i'm using is kind of oilly.

Re: a/c install do you need a negitive vac
 

Oily flush is very bad. You will never get it all out. The best flush is liquid refrigerant, but that is pricey and most shops wont bother doing it correctly because it is cost prohibitive to the customer. Admittedly, we dont. So the next best alternative is something like this
http://www.4s.com/Problem%20Solving%...I/Content.aspx
it evaporates fairly quickly and only a minute amount will be left over, unfortunately it is corrosive and can damage seals and the orifice tube(doesnt apply to you obviously) it is not common but it CAN happen, however it is a hundred times better than any "oily" flush you may use.