Tempstar, TXV, R-410a,compressor, etc problem

Sooo
I went out to the Tempstar N4A360 condenser with the Internal pressure
relief opening problem today.
By the way, this unit is a one speed condenser motor and has NO low
pressure or high pressure switch, no high temp switch or anything
else.  :-)
Owner said it had been opening and making noise several times a day
now. I unload my tools from the truck and after about 10 mins the A/C
still hasnt cycled on, on its own. I went in and turned the stat down.
It was set on 76 and it was 76 in the home. The unit came on and
immediately I heard it running with the relief valve opened. I already
had gauges on it and it was showing about 175 on the suction and about
275 on the head. I pulled the disconnect, waited about 5 secs and
turned it back on. Unit ran just perfect and quietly. I checked the 11
degree subcooling and it was right on. For ****s and giggles I pulled
the condenser fan wire and watched the head pressure climb. About 25
seconds later with me stepping slowly backward I watched it climb to
750 psi before the relief opened. (So now you all know what they open
up at). Cant quite say I want to stand near a unit that does that
again. Anyways, word is that a certain batch of units may need to have
the factory installed R-410a refrigerant charge removed and recharged
with new virgin refrigerant. I pulled the crap out and saved it so I
can do a press/temp check on it to see if it jives with the R-410a
chart. (Yes, I pulled a vacuum on the tank and my recovery machine
before I dumped the crap in the tank). Pulled a 500 micron vac on the
system. While waiting, I found the sensing bulb on the Aspen coil was
mounted horizontal at the 6 oclock position with no insulation on it.
Not sure if it came that way or we mounted the bulb but that was our
fuquer up. (I did the outside unit. Employee did the inside unit.)
Corrected that and put it at the 4 oclock/8 oclock position and
insulated it. Measured the 22 ft lineset and recharged the unit. 
Works fine now but time will tell if that does the trick or not??
Bubba