Charging A/C System

[SVXMAN2001]

I've done some researching before posting however am still a little confused about the charging process for a 92 SVX a/c system.

Background: I am replacing every component within the a/c system (Compressor (rebuilt); lower pressure hose (muffler); High pressure hose from compressor to condensor; condensor; high pressure line with trinary switch from condensor to drier; new drier and new expansion valve. I will be flushing the high pressure line from the condensor to the evaporator and the evaporator itself (these are the only two parts I am reusing).

So my questions concerns are:

1) The manual states to initially charge through the high side (with engine OFF) while in liquid form? I am not all too familiar with this but my can of freon seems to be in liquid form? the only reason I bring this up is because once a can is used up on the high side, the manual states to finish charging on the low side with remaining freon in vapor form???

From what i've read a lot of systems charge only on the low side, why is this different on the svx?

2) I need to purchase a vacuum pump, does anyone have any suggestions?

3) I am sticking with r12 and need to use compatible oil for the compressor and fittings throughout the system. What type of oil should i be using?

4) Anyone have a set of r12 gauges they would be willing to lend or sell?

4) Has anyone installed an in-line a/c filter? I did a little research on the internet and some of these require cutting of the OEM piping...not too fond of this idea.

Thanks in advance for any help/suggestions, thanks Chris

[msvx95]

I am very interested in someone knowledgable on this subject too. I disconnected one of the lines to the a/c compressor while removing my intake and I believe I have to recharge the system now.

[dcarrb]

I don't know if it matters—probably not—but be mindful that a reman compressor may be intended for an r134 system.

dcb

[SVXMAN2001]

Funny enough, after searching the forum's I went with your suggestion and get a reman from 1airconditioning. The instructions indicate that the oil used is compatible with both r12 and R134a systems. That and the reman is specifically for a 92 model. So I think i am set on that front.

[Conn SVX]

Y are you staying with the old r12. iT WILL BE HARDER TO GET EVERY YEAR. bOTH MINE HAVE BEEN CONVERTED AND THEY BOTH CAN FREEZE ME OUT OT THE CAR. sORRY SHIFT LOCK STUCK

[kwren]

Originally Posted by Conn SVX

Y are you staying with the old r12. iT WILL BE HARDER TO GET EVERY YEAR. bOTH MINE HAVE BEEN CONVERTED AND THEY BOTH CAN FREEZE ME OUT OT THE CAR. sORRY SHIFT LOCK STUCK

r-12 IS FINE! wITH WHAT YOU ARE DOING, YOU SHOULD BE GOOD FOR YEARS!

kEITH

[kwren]

I personally would evacuate the system, close the port and remove the vacuum pump, connect the hose to the high-side from the inverted refrigerant can, open the high side port and charging port on the can to get as much as possible of the liquid in the system, when this is accomplished, close the "high side valve and close the valve on the can, start the engine and set climate control to allow the air condition compressor to come on, then connect the hose to the low side and slowly put the rest of the liquid refrigerant in the system... as instructed with the charging kit. This is of course with the proper charge size of refrigerant.

You are to be commended for attempting this project and I'll bet you can pull it off!!

Keith

[kwren]

Originally Posted by SVXMAN2001

... my questions concerns are:

1) The manual states to initially charge through the high side (with engine OFF) while in liquid form? I am not all too familiar with this but my can of freon seems to be in liquid form?

Freon is in liquid form when under pressure. As the pressure is decreased, freon boils and makes a vapor just like water does when you boil water... you get steam, or a vapor. However, Freon boils at a much lower temperature than water does. Depending on the chemical composition, it varies somewhere below zero, but all refrigerants boil quite a bit below zero. The cold vapor from the boiling is what makes the refrigeration system cool.

When the system is properly evacuated with a vacuum pump, the proper way would be to pull down the system into a vacuum condition, seal off the vacuum in the system with the valves connect the hose from the can of refrigerant to the hi pressure side, open the valves, on the can and on the compressor with the can inverted, and let the liquid refrigerant flow in.

As the system begins taking in the liquid freon, at some point the pressure in the system and the pressure in the can of freon will become the same, so there will be a portion of freon liquid that will remain in the can.

...the only reason I bring this up is because once a can is used up on the high side, the manual states to finish charging on the low side with remaining freon in vapor form???

There is your answer. The suction side will be enough difference in pressure to allow remaining in the can of freon to get the majority of it into the system through the lo side, as the compressor is operating.

From what I've read a lot of systems charge only on the low side, why is this different on the svx?

Charging on the hi side would be a safer way to charge the system without risking damage to the compressor.

Thanks in advance for any help/suggestions, thanks Chris

When charging on the hi side the freon can must be inverted to get the liquid out.

Hope this helps.

Keith