Weird Pressures Readings

HH brown

hello everyone i'm a newbie in the trade and, as the
title reads "weird pressures readings" is what im getting. customer had someone put a 1 1/2 ton split sys. in and the person just ran off with the money. so customer calls another contractor and my company sends me.
so the previous contractor only installed the duct work, ahu and, ran line set. when i got to the condeser i noticed he (the first contractor) never brazed in the lineset so the line just sat exposed to to he atmosphere. so the first thing i did was braze line set (along w/ liq.filter) in, pressure test, and pulled vac. so now im ready to charge. i dump about 5 pound in and turn unit on and my lo side pegs out and the hi side was steady creeping above 350psi. so i shut disconnect to save compressor. why was this happening? metering device was fine no crap was in the orifice. what went wrong?

HVAC Doc

Hmmm going to ask a seemingly stupid question here but were the service valves open? Is this a brand new unit or used? I ask due to the fact you said you added about 5lbs to the system. What is the factory charge specified on the nameplate of the system? How deep a vacumm (how many microns) did you pull?

HH brown

hvac doc, the unit had no refrigerant when i got there. i pulled the vacuum down to 29in. i checked to see if it held, which it did. the unit was supposed have 4 lbs of r-22 which was only enough for 15ft of lineset. the reasson i added an additional lbs was to compensate for the extra 5 ft(unit is mounted on the roof) i used the chart thats attached to the unit . thanks 4 your response