This week I tried AC for the first time this year and it will run fine for about 10-15 minutes and then it will stop blowing cold. I connected one of those cheap gauges that comes with a recharge kit and the pressure moves well into the red zone and then it sounds like the compressor will kick in and the pressure will drop into the yellow zone - still higher then the indicated green pressure zone on the gauge.

So I am wondering if I got too much coolent and if instead of a recharge I need to bleed some off? Or are Volvos supposed to run higher then other vehicles and the recharge kit's gauge is too generic?

And if I need to bleed some off can I do it or does that require an AC shop so I don't kill the planet?

Mine did the same exact thing cheapo gauge jumped up real high and dropped fast with the compressor cycle but it still cycled about every 5 seconds.So I put in a can of freon, and all fixed. Works great now has for about a month and a half. I wouldnt worry about connecting to the wrong one the hose only fits on the right one and that is really the only one you see.good luck

There's high side pressure and low side pressure. I don't have the specs but you must get them before something gives.
A set of A/C gauges is a must so you can tell if the condenser, compressor are working properly or if you have a contaminated system or worse, a restricted system.
Pressure is measured normaly at 70 deg. ambient temperature and from there it is compensated for variations plus or minus.
Make sure the fan is turning ON and not allowing the pressure to rise too high on the high side.

Set fan on speed 4, roll all the windows down, then turn on A/C and measure. If it keeps cycling on and off, and you see the pressure jump and drop, then you are probably low. Add just about 1/2 can of freon, then re-check the A/C gauges. Ideally, you want to check at 70 degrees F, but a "warm" day will do. You want to make sure that the pressure holds at a steady 30ish p.s.i. Bleeding the A/C is not the best idea b/c you'll also let out oil from the system, and you have to drain out all the oil, then refill to make sure the system has the proper amount of oil. Too much or too little oil can damage or ruin the compressor. With the A/C off, you'll get a high reading, like around 70-90. During normal operation, you should get a stable 25-35, ideally around 30. Hope this helps. Good luck! And by the way, while R-134a WON'T deplete the ozone layer, it is still a greenhouse gas. I've also noticed that many R-134a systems have a "sweet spot". Too little refrigerant and it obviously won't cool at full performance, but once you start to overcharge the system, the cooling capacity drops as well. Again, at 30 psi you should be pretty close to the "sweet spot".
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'94 854 N/A.