Issues getting refrigerant to charge

[evan1234321]

Hello,

for the life of me I cannot figure this out. Acquired a new truck, ac blows hot. Manifold gauges I rented at parts store show low and high side are both at zero psi. I ran a vacuum pump for about a half hour or so, then went to add r134a. The truck wont accept the charge. The point of this was to add a charge with some dye, maybe enjoy ac for a little while before it all leaked out, find the leak and fix it. However The Freon makes it into the gauge but sits there. I noticed the compressor isn't spinning, which I assume is from lack of refrigerant. Okay, cool I'll just jump the low pressure switch. So the compressor is now spinning, but Freon will not make its way into the system. low side reads 90psi when I release the valve for the can. Low side is open at the gauge. I dispel air at the gauge and it falls back to zero, and then that's it. High side is closed at the gauge. Car is running with AC on. Any ideas are much appreciated. I would also add that this truck previously had ac and was working.

Respectfully, please fight the urge to tell me I'm in over my head and to take it to a professional. I'm using this as a learning experience, thank you.

 

[Motorcity muscle]

With gauges attached did it show a vacuum with pump on? Have done this before?

 

[07navi]

Don't give up yet there are some ac semi pros in here. Is the compressor spinning now? Is the ac turned on high inside? Do you have the round gauges with the hoses (sold online cheap), are you using the ac cans and how many? Are your Schrader valves(s) free?.

 

[evan1234321]

With gauges attached did it show a vacuum with pump on? Have done this before?

Thanks for the reply. Yes the gauges displayed 30hg on with vacuum pump running. When turned off vacuum drops back to zero. And yes, I'm by no means a pro but I've done a few projects before back in tech school.

 

[evan1234321]

Don't give up yet there are some ac semi pros in here. Is the compressor spinning now? Is the ac turned on high inside? Do you have the round gauges with the hoses (sold online cheap), are you using the ac cans and how many? Are your Schrader valves(s) free?.

Thank you I appreciate it. Yes, the compressor spins when I jump the low pressure switch. Ac is turned on High with fans on max (not recirculating). I have the standard manifold gauges you can rent at AutoZone. The ones with the three lines and red and blue round gauges. I'm using three 12oz r134a cans as the manual stated it required 33oz. By "Schrader valves(s) free," do you mean is there blockage? If so, no. I depressed both high and low side schrader valves just to see if there was indeed zero pressure and I got a little bit to come out, then nothing. I believe the system is completely empty on both sides.

again, I really appreciate any insight. I'm going mad, lol.

 

[Motorcity muscle]

System should hold a vacuum, when you close gauge port on gauges and turn off pump. Need to pressurize system and locate leak. Can use air pressure to check for leak but dry air or nitrogen.

 

[07navi]

It sounds like it is leaking so fast that it wont take any charge, do like Chris said.

 

[evan1234321]

System should hold a vacuum, when you close gauge port on gauges and turn off pump. Need to pressurize system and locate leak. Can use air pressure to check for leak but dry air or nitrogen.

Vacuum holds with pump off and gauges open for about 2 min or so. Is the method of charging via r134a cans unusable at this stage? I was under the impression that the can was enough to pressurize the system on its own. I'm confused as to how an ac shop machine would do any different. Evacuate, vacuum, then charge.. correct? Does the system need initial vacuum to draw in the refrigerant? I will look into pressurizing with air next as you recommended.

 

[07navi]

It sounds like you have a big leak that needs to be fixed first. Use air pressure and soapy water to find it.

 

[fuzzmanmatt]

Are you using the new self-sealing cans? Those suck, sometimes you have to back off the valve on them a bit to get them to work. See if you can find a buddy with a keg, those tend to work better with most gauge sets.
Your system should hold vacuum for hours. Come back and check it now that it's sat, if it's still got vacuum you're good to go.
If that's the case, fiddle with the knobs, jiggle the cans, sometimes you can get those seals on the small cans to release and do what you need. Good luck!