Charging the AC system thru the HP side
 

I know this has been discussed, but I can not find the reasoning behind it....

Why should the AC system be charged thru the HP side with liquid, i.e. the bottle valve down? The manual only tells us to do this, but not why.

A brand new compressor arrived yesterday :-).

Thanks,

Tapani

Re: Charging the AC system thru the HP side
 

I would think you only do it on initial charge, as the compressor would not have anything in it and would need it added first to allow it to turn on.

and only with the a/c system NOT on as you dont want high pressure suddenly pushing the freon back into the can and exploding.

Re: Charging the AC system thru the HP side
 

The service guide also mentions toggling off compressor with economy switch to avoid shock to compressor every so many seconds.

Re: Charging the AC system thru the HP side
 

Yep,

http://autoforums.carjunky.com/Autom...YSTEMS_P45460/

So the FSM method is just "pre-flooding" the system + gas charging. Not "liquid charging" as described in the link.

Tapani

Re: Charging the AC system thru the HP side
 

charged thru the HP side with liquid is a way to get the correct amount of refrigerant in the system but either way with a new compressor a vacuum has to be pulled on the AC system. To charge the HP side, a vacuum must be pulled in all cases to allow the refrigerant to be sucked in. I personally see no advantage over charging HP over LP. in doing this. I personally charged my SVX on the low side with gas rather than liquid. I am able to do this without even using a pressure gauge. This requires a certain amount of expertize, but for the average person charging through the LP port works better with a gauge to monitor the pressure.

The svx has built in safety components to prevent continuous compressor operation when if the system is overcharged.

Actually liquid refrigerant could possibly gather in the wrong part of the system could possibly cause compressor damage.

I would recommend charging on the LP with gas.,, Of course, ALL "0" ring seals must be replaced with new ones!

Keith:cool:

Re: Charging the AC system thru the HP side
 

Do you know what size they all are? I have new ones for the compressor (R134a unit).

Also, the drier was replaced 8 months ago - should I swap that again? No leaks in the system.

Thanks,

Tapani

Re: Charging the AC system thru the HP side
 

8 months ago? You are good!!

Keith:cool:

Re: Charging the AC system thru the HP side
 

yah, I would avoid unhooking anything uncessary to the job. Every time you open a joint in the system you increase the chance of a leak at that point.

What they mean about the HP side filling is mainly for oiling the system and getting gas in there so the system isnt running completely dry, causing damage to the compressor.

Any filling from a DYI 134a refill kit should NEVER be hooked to the high side. You will have frozen, shredded hands after the can explodes.

If you've had the system open, you really should put a vacumn on the system to remove water/impurities/air from the system. I skipped this step when I redid my system and I'm regretting it now.

You also mentioned something about the bottle valve down. NEVER turn a 134a can upside down when filling. If you've ever flipped a can of Duster upside down, or spray paint you see what happens. It will freeze the valve, your lines and possible cracking the rubber hose between the valve and the can.

Re: Charging the AC system thru the HP side
 

See the FSM. It explains the procedure to "flood" the system with liquid R134a prior to actual "charging".

T

Re: Charging the AC system thru the HP side
 

I realize the fsm might say that but remember that fsm was written 20 years ago. I'm speaking from experience. I worked at a shop recharging AC for a few years so I've done it both with a 5k dollar AC recycling/refilling machine and done it without the machine.

You sound stuck on doing everything the FSM says, but are you even putting a vacuum on the system? Theres no point in following just one step and none of the rest... All thats doing is setting it up for failure and injury.

Let me know how your fingertips are doing after flipping the can

Re: Charging the AC system thru the HP side
 

I think you missed my question, mate.

Tapani

Re: Charging the AC system thru the HP side
 

AC is ice cold !

New R134a compressor, new drier, retrofit fittings for the service ports, new O-rings only to the joints I had to open.

The compressor had PAG oil in it, added another 25 grams with the machine. Charged with 500 grams of R134a - the manual calls for 650 grams for a "real" R134a system (same amount incidentally also for an R12 system) - if I am not mistaken retrofits are usually charged with a little bit less if the major components are not changed (condenser mainly). So everything else is stock R12 - let's wait and see the long term operation.

Around 23 C ambient and @1750 rpm the high side is 215 PSI and the low side 24 PSI. Good enough with the R12 expansion valve.

Tapani

Re: Charging the AC system thru the HP side
 

Congrats! You should do a 'how to' or a youtube video:D Good luck and enjoy!

Re: Charging the AC system thru the HP side
 

Update on this.... The system was ok for three years.... Just a while ago the compressor did not turn on anymore. I checked the pressure switch - it was open - too low pressure.

Evacuated and it held vacuum real nice. Recharged with 500g and it's ice cold again.

Cool ��

T