L9000/Fld daycab ac

2 lbs seems a little low.

 

Get your high pressure up to about 300 and low about 30 , when the fan cycles you will know you have it

 

My bucket of bolts takes 3.5 if my memory is correct….

 

3.75 lb is stated on the sticker if my 2002 Century with sleeper and a Sanden S7 compressor. 2lb is probably a little on the low end. 3.75 lb usually charges down to 50°. Charge when outside temperature is cool, if you didn't. And I use silicone seals only. They seem to hold up better-over time for sure.

 

I agree with everyone. 2 lbs. and 20 psi is low. 3 lb.7 oz. on my FLD. 55oz. I put 5 cans, 60oz. Bleed air from line after connecting each can. Works perfectly every time. Unless there’s a problem. Might want to add slowly, giving it plenty time to circulate before making conclusions. When using my Official Guesstimating chart, before I had gauges, I found that filling it, while the compressor is constantly running till the compressor cycles off for the first time. Stop. That’s usually pretty close. Fully charged, the clutch should stay engaged longer than not. Up to twice as long. Much longer, it’s probably low. Cycling off longer than on, it’s overfilled. Running it low will cause the compressor to run hot, and shorten its life. You need that last 12oz. or ? to keep up on real hot days. Mine usually runs at 35 low side. But on real hot humid days, up to 55 when completely full.

 

280 psi on the high side? If so, that should do. I get 300 psi high side and 40 psi low side when maxed out at 3.75 lb of refrigerant. I charge a little less anymore to get more time out of system before a failure occurs.

 

BTW, did you use a vacuum pump before charging? I think that's important. Removes moisture as well as air to allow more refrigerant upto pressure limits. Can get one at Harbor Freight relatively cheap.