I have a Bryant 2 ton ac unit. It had a leak in one of the lines lost some refrigerant maybe all of it.Hooked my gauges up to it no pressure on either gauge.hooked up R-22 tank set inside thermostat to for lowest setting. I can hear the click in the outside unit but compressure does not start. I push contractor in and it will start put when I take my finger off it stops.How do I recharge my system.PLEASE HELP