Orifice Tube and Low Pressure Switch bypass

[pp270]

1. Where is the orifice tube located on a 2000 GT GP?

2. How do I by pass the low pressure switch so the compressor clutch will engage to accept more freon and recharge the system? The system is out of freon so is currrently holding no pressure.

I have dual climate control with a V5 compressor.

[richtazz]

the orifice is located in the high side line on the drivers side of the vehicle near the accumulator (under the hose between the air filter box and the t/body.

Because there is only one pressure switch, it cannot be easily "jumped" to force the compressor to kick in.

[pp270]

How do I then force the compressor to engage the clutch to accept freon during a recharge. All of the freon leaked out because of a poor shaft seal on the compressor. I already replace the compressor.

[BNaylor]

You should get enough pressure or refrigerant charge to overcome the low pressure side of the switch with the first can of R134a and eventually the compressor should kick in. I had no problems with a fully evacuated system that required work on the V5 compressor.

[doctorhrdware]

As long as a vacuum has been pulled it should take the freon charge. But is there was no vacuum it is very hard to get the system to take an initial charge. Plus since the system was opened to replace the compressor you need to pull a vacuum in order to boil off any moisture that entered the system when the compressor was replaced.

[BNaylor]

Isn't evacuating a system the same as pulling a vacuum on the system which is standard practice or auto A/C 101 basics?

Or maybe we should parse the term "recovery".

Evacuate A/C system

Evacuating an A/C system is the process of pulling the A/C system into a vacuum. This is one of the most critical processes when recharging or servicing any automotive A/C system and often one of the most misunderstood processes.

Vacuuming an A/C system has no effect on cleaning or removing debris or contamination. The only function of pulling vacuum or evacuating and A/C system is to remove all the air from the system. Removing air will also remove any moisture that may be in the system.

Removing both air and moisture is critical to the proper operation of an A/C system. Air is a non-condensable gas. Leaving air in the A/C system will cause excessive high side pressures and lead to poor cooling performance. Excessive high side pressures will also create greater loads on the A/C compressor leading to premature failure. Additionally, moisture in the system, once mixed with refrigerants will create acids that are harmful to the system. Those acids cause internal corrosion of A/C system components. That leads to leaks in A/C condensers and evaporators.

Whenever pulling a vacuum on an A/C system, it�s critical that the vacuum pump used is capable of pulling deep vacuum, typically under 500 microns. In order to determine proper levels of vacuum, a micron vacuum gauge should be used.

Most manifold pressure gauges include a compound pressure gauge for low side pressure readings. The compound gauge allows the gauge to read levels of pressure and vacuum. The problem is that the vacuum scale on the compound gauge is so small that it is really difficult to tell what level of vacuum is really being attained. Besides, inches of mercury are not as accurate for measuring vacuum as microns.

Microns are only a different scale of measurement. One micron equals one millionth of a millimeter. When comparing levels of vacuum in microns and inches of mercury, understand that 28.9 inches of vacuum is only equal to about 25,000 microns. On the other hand, 29.9 inches of vacuum is almost 50 microns. The lower the number of microns means the better level of vacuum.

When using just compound pressure gauges, it is almost impossible to tell the difference between 28.9 and 29.9 inches of vacuum. What complicates matters even more is that you need to understand water will not boil until a level of vacuum under 1,500 microns is achieved. The vacuum scale on a compound pressure gauge can not assure you that the proper level of deep vacuum is being pulled. For those reasons, vacuum pumps should routinely be checked with a micron vacuum gauge in order to assure that they are pulling the deep vacuum that is required whenever servicing auto A/C systems.

http://youracauthority.com/acterms/E...C-system.shtml

[doctorhrdware]

Yes it is the same thing. Been kinda of out of it with a lot of lower back pain. This weather sucks when the temps at night go down to the mid 50.