Recharging A/C Using Cans - PeachParts Mercedes-Benz Forum

Adriel · #1 06-25-2016, 05:50 PM

With a "professional" installation, the refrigerant and the oil are installed separately, correct?

If one is using a can that contains 10 ounces of refrigerant and 1 to 1.5 ounces of PAG, then how do we obtain the proper oil levels and not have the compressor run dry or slugged?

Thank y'all in advance for the help!

leathermang · #2 06-25-2016, 06:05 PM

Yes, and put at more than one point in the system... to help it get dispersed evenly and mixed into the refrigerant fast....as to not starve the compressor particularly when using the R4 which has no oil sump...

tyl604 · #3 06-25-2016, 06:17 PM

Leather - I think he is asking how to do it and achieve the proper mixture.

vstech · #4 06-25-2016, 06:23 PM

Since you chose to use oil/refrigerant mixes its tricky... you should reduce the compressor oil quantity by the amount of oil the mix contains, then pour into each coil and the dryer 1.5 oz of oil. That way you dont slug the compressor with oil, and you dont get oil starved compressor.

Note...

This is ONLY advice for the sanden compressor... the R4 system is different, and i would then recommend charging IT after the correct oil was in the coils and dryer, and the mix would flow through the compressor...

leathermang · #5 06-25-2016, 06:25 PM

I was only answering the question I knew the answer to...

I do not recommend using a can for oil insertion... ... as this is one problem with that method..
if you have premium cold flow oil in a newly opened container..... then it can be poured into the various parts as they are installed.... assuming that one does not have the ' under pressure' device shown in the AC FSM... if not using the standard procedures then some things have to be guessed at...

vstech · #6 06-25-2016, 06:33 PM

This is yet another reason i do NOT RECOMMEND charging a fresh system from cans...

After the leak check is confirmed tight, then the vacuum is pulled, 10 oz isnt enough refrigerant to really break vacuum... and how are you vacuuming the system, then attaching a can? Vacuum needs to be treated with respect... itll pull in moisture if you swap cans, and hoses from the vacuum...

Itll pull in air and moisture if you disconnect hoses from vacuum...

A hard vacuum, then dumping in an entire can into the liquid side WITH THE COMPRESSOR OFF... would get oil into the condenser... then after pressures equalized, you could start the compressor and slowly flow the oil and refrigerant into the low side...

leathermang · #7 06-25-2016, 06:48 PM

And the new hoses typically have no way to ' bleed' as we used to.. hook up leave the connection loose , open the refrigerant valve , and let it escape to blow out any air and moisture in the line...

Adriel · #8 06-25-2016, 07:40 PM

Quote:

Originally Posted by vstech

This is yet another reason i do NOT RECOMMEND charging a fresh system from cans...

After the leak check is confirmed tight, then the vacuum is pulled, 10 oz isnt enough refrigerant to really break vacuum... and how are you vacuuming the system, then attaching a can? Vacuum needs to be treated with respect... itll pull in moisture if you swap cans, and hoses from the vacuum...

Itll pull in air and moisture if you disconnect hoses from vacuum...

A hard vacuum, then dumping in an entire can into the liquid side WITH THE COMPRESSOR OFF... would get oil into the condenser... then after pressures equalized, you could start the compressor and slowly flow the oil and refrigerant into the low side...

John, thank you so very much for the help!

Hmmm, I am confused...

Would 16 ounces of R134a be better? I have a 16 ounce can of the mid grade that could use if it will avoid moister draw.

Just so clear, how much R134a?

The R4 has 6 to 8 ounces distributed, where Sanden has it specified as 5 in the compressor and 1 ounce in the drier.

If I am understanding correctly, proceed as follows:
1 ounce of oil in the condenser
1 ounce in the drier
19 ounce can with about 2 ounces of oil and 16 ounces of R134a in the high side without the compressor running
Two 12 ounce cans with 1.5 ounces of oil in the low side with the compressor running

This gives a total of 36 ounces of R134a and no more than 7 ounces of oil.

Or, can skip the drier (which accumulates extra oil) and then only 6 ounces.

leathermang · #9 06-25-2016, 07:44 PM

""Two 12 ounce cans with 1.5 ounces of oil in the low side with the compressor running"""
I am not confirming anything in your post... but I am suggesting you check this placement as with it on the low side it might be too close to the compressor... do not want liquid refrigerant or oil to hit the compressor...

Adriel · #10 06-25-2016, 07:47 PM

Quote:

Originally Posted by leathermang

""Two 12 ounce cans with 1.5 ounces of oil in the low side with the compressor running"""
I am not confirming anything in your post... but I am suggesting you check this placement as with it on the low side it might be too close to the compressor... do not want liquid refrigerant or oil to hit the compressor...

Okay, I am dyslexic, so that seems to make since to have the compressor off.

So, revised:
Proceed as follows:
1 ounce of oil in the condenser
19 ounce can with about 2 ounces of oil and 16 ounces of R134a in the low side without the compressor running
Two 12 ounce cans with 1.5 ounces of oil in the high side with the compressor running

leathermang · #11 06-25-2016, 07:56 PM

Adriel , that is not exactly what I mean...
perhaps it would be safer to put the oil into the Txvalve opening in the evaporator... that is still on the low pressure side...

that way I think the possibility of pulling liquid oil into the compressor WHEN the Compressor does turn on is lessened....

be sure it is the INPUT of the evaporator... the hole in the evaporator that the Txvalve is feeding..

Be sure that the refrigerant you apply to the LOW side is in GAS form... from the top of the can .. .away from the earth ' top'...

ROLLGUY · #12 06-25-2016, 11:58 PM

Quote:

Originally Posted by vstech

This is yet another reason i do NOT RECOMMEND charging a fresh system from cans...

After the leak check is confirmed tight, then the vacuum is pulled, 10 oz isnt enough refrigerant to really break vacuum... and how are you vacuuming the system, then attaching a can? Vacuum needs to be treated with respect... itll pull in moisture if you swap cans, and hoses from the vacuum...

Itll pull in air and moisture if you disconnect hoses from vacuum...

A hard vacuum, then dumping in an entire can into the liquid side WITH THE COMPRESSOR OFF... would get oil into the condenser... then after pressures equalized, you could start the compressor and slowly flow the oil and refrigerant into the low side...

Agreed. You are better off having it done by someone with a recovery/recharge
machine, and it will be done correctly. There is too much guess work involved by using cans. If you want to use up the cans you have, your local A/C shop should have a way to recover the refrigerant from your cans, and credit you that amount when your car is charged by their machine.

Adriel · #13 06-26-2016, 12:06 AM

Quote:

Originally Posted by ROLLGUY

Agreed. You are better off having it done by someone with a recovery/recharge
machine, and it will be done correctly. There is too much guess work involved by using cans. If you want to use up the cans you have, your local A/C shop should have a way to recover the refrigerant from your cans, and credit you that amount when your car is charged by their machine.

Rich, where would I get the funds to pay for $90 an hour of labor? Last time had A/C work done at a D.Y.I., that is what they charged and messed up the system; rip off in many ways. I love to find that and get the guide rod mounts done. I seriously make $60 to $90 a week and don't have any credit options. And no, bills don't get paid. I have lived without water and electricity; they give a few months grace before shut off. Amazing how little we need in life.

My friend will charge me nothing and has done cans before, more than a couple, just don't want to lie about the amount.

But, if find a resource, change mind.