Vintage Air Compressor Will not come on

[TnBlkC230WZ]

I'm finally getting the AC system charged and I hooked up the compressor wire. I expected the compressor to cycle on when I turned the system on, but it didn't. I have a trinary switch installed. There is no power at the compressor wire.

Will the compressor run before the system is charged or does it have to have refrigerant in it for the trinary switch will allow the compressor to come on?

Edit: I do have power going to the trinary switch, but power is not making it to the compressor

[dhutton]

You have to charge the system. The switch will not apply power to the compressor if the pressure is too low or too high.

Some good info in here:

http://www.vintageair.com/DownloadsS...2806)-Inet.pdf

[TnBlkC230WZ]

Thanks, I was hoping it was a low pressure issue. I just wanted to make sure it was working before I took it in to be charged.

[TnBlkC230WZ]

I got it charged and it is blowing cold. The mechanic told me to lose the trinary switch and wire the fan to come on with the compressor. He said the AC will stay colder if I keep air moving across the condensor. The fan does cycle alot.

[dhutton]

I got it charged and it is blowing cold. The mechanic told me to lose the trinary switch and wire the fan to come on with the compressor. He said the AC will stay colder if I keep air moving across the condensor. The fan does cycle alot.

Somehow it does not seem like a good idea to have your fans running while you are going down the highway. I would stick with the trinary switch, they are only cycling while you are idling. Once you are moving they should stay off.

[TnBlkC230WZ]

Somehow it does not seem like a good idea to have your fans running while you are going down the highway. I would stick with the trinary switch, they are only cycling while you are idling. Once you are moving they should stay off.

80% of my driving is in traffic. With the Dakota Digital fan controller, it is very easy to switch between the two. If I don't see a difference with it to the compressor or plan a trip, I can put it back. I'm curious if it makes a difference it the air temp. Sitting at idle, it is definitely not as cold. I am running a small SD7 compressor.

[Twentyover]

You're mechanic is an idiot.

The trinary has three functions, compressor control at low pressure, compressor control at high pressure and fan control at intermediate pressure.

A trinary's only reason for being is to increase fan speed or implement fan actuation at intermediate pressure to reduce that irritating fan noise on a luxo cruiser. The remaining two functions can be handled w/ a binary. Wire the clutch and A/C fan actuation through the switch- it will protet the compressor at both low pressures (low charge) and high pressures (usually blocked airflow over the condenser.)

The trinary may be wired to implement the fan at intermediate pressure- as dhutton indicates, there MAY be enough airflow at speed to not require the use of an engine cooling fan at these conditions.

[parsonsj]

Your mechanic is wrong (just to pile on).

Use the trinary switch. What Greg said.

jp

[TnBlkC230WZ]

I will leave it in then. A different question. The AC doesn't get cold when it gets above 93 or 94 degrees. It isn't very cold to start with. I am missing my door panels and back seat, but I thought it would be colder.

[parsonsj]

I'd make sure you have a full charge. Do you have a thermometer? You need to measure the temp of the air coming out. Put your A/C at max, fan speed about 3/4. You should get air temps in the 30s or low 40s, depending on ambient.

jp

[TnBlkC230WZ]

I'd make sure you have a full charge. Do you have a thermometer? You need to measure the temp of the air coming out. Put your A/C at max, fan speed about 3/4. You should get air temps in the 30s or low 40s, depending on ambient.

jp

I only have my hand, but it is now where near 40 degrees. Maybe 70 when the ambient is 93 - 95.

[Twentyover]

You really need a thermometer. Also, the system needs to be evaluated at about 1500 rpm engine speed.

A refrigerant's boiling temp is very pressure dependent- at the evaporator suction pressure ranges, a 1 psi drop in suction pressure results in about a 1 degree change boiling temp. At idle, the compressor isn't turning fast enough to develop really good suction pressure.

That said, you need to determine if the evap is reaching it's potential, or whether you are re-introducing heat in the system. Park it in the shade, let the engine cool overnight (I'd suggest a garage if available) wait until the outside air warms up, start the car, run it at 1500 rpm, and measure outlet temp at full cold. This way you're not introducing heat through coolant temp or solar heatimng the dash.

This will tell you if the problem is in the refrigerant loop or elsewhere. Another quick check is to see if there is condensate forming on the accumulator (if ccot type) or on the suction tube from the evap or on the tube between the R/D and evap (could be plugged R/D)

Is this a factory A/C system or aftermarket? How is temperature controled? Vacuum motor, servo motor, or bowden cable? Does the system use a TXV (R/D on the small diameter discharge tube) or orfice tube (accumulator on the suction side of the evap?)

[parsonsj]

You really need a thermometer, but here's what Rick Love (Vintage Air VP) once told me:

Use the back of your fingers and let the vent blow on to your fingernails for 30s or so. That should make them tingle/feel numb with the cold (like when you're outside and wished you had gloves).

jp

[TnBlkC230WZ]

I'll get a thermometer and do the tests suggested but TwentyOne. It is VA Gen 4 system for a 1st gen Camaro that I put in my Nova. They are very similar cars. I'm running a Sanden 7 series compressor that is pretty small, but it is being overdriven by the March Pullies. It is the same compressor on the front runner system and my March pullies are designed for this compressor.

[Twentyover]

Still need the 1500 rpm. I'll keep saying it until you can show me a 28-30 psi suction pressure at idle

On a Gen IV make sure the water valve is closing

[TnBlkC230WZ]

On a Gen IV make sure the water valve is closing

I need to check the obvious. That wire does come loose. I need to tighten it.

[TnBlkC230WZ]

I checked the valve and the wiring is tight. I took the hose off and I'm not sure if the valve is working correctly. I see it move a little, but I believe the valve should go all the way down and stop the flow. The electric coil that controls the valve got very hot, too hot to touch.

I measured the AC temp and it was 76 degrees with an ambient temp of 83 inside my garage. The -6 line was hot and the -10 line was warm when I touched them at the fire wall. There was no condensation on the lines.

I measured the temps when the engine was still cold so the heater wouldn't be hot and it didn't get cold.

Any ideas?

[dhutton]

Did your mechanic use the Vintage Air charging instructions and charge it with the specified amount of R134 or did he just charge it up like he does normally? VA systems run at lower pressure than most systems if I remember right. Did you give him the instructions? It clearly states 1.8 pounds of R134.

[TnBlkC230WZ]

Did your mechanic use the Vintage Air charging instructions and charge it with the specified amount of R134 or did he just charge it up like he does normally? VA systems run at lower pressure than most systems if I remember right. Did you give him the instructions? It clearly states 1.8 pounds of R134.

Yes, I gave him the instructions. When they got done, they said the air was cold, but I've never felt cold air. They are VW factory certified techs and friends/enthusiasts. If he said it was cold when he got done, I believe him.

[Twentyover]

Then there's a leak or another problem. The system's not working as designed.You need to get a set of gauges on the system and get pressures.