What is the proper way to check the charge on a heatpump in the heating operation. Would it be sub cooling on the high side or what. Some times I have put it into cooling just to see if I'm close, but I know that is not close outdoor temp here is only about 60 to 55.

Actually the best way to service a heat pump and check for the proper charge is to recover the refrigerant in the system and then weigh in the refrigerant charge according to the chart on the unit. All else is guess work because there are to many variables.

What is the proper way to check the charge on a heatpump in the heating operation. Would it be sub cooling on the high side or what. some times I have put it into cooling just to see if I'm close, but I know that is not close outdoor temp here is only about 60 to 55.
Agree with above answer... if unsure on charge... recover and weigh in at manufacturer specs... gmc's way of checking in heat mode is to get a good measured temp of your line... should be around 125 degrees higher than outdoor ambient. That is pretty close.. and your suction pressure should be around outdoor ambient... but going from spec sheet with actual heat pump is the most accurate.

Thanks for the help. The 126 plus ambient temp is close but like 69 plus 126 is 195 line temp.
Still seems high. Tranes chart is OK , but carrier and goodman and lennox don't have a chart should I use the same idea as 126 plus ambient? With an outdoor TXV why can't sub cooling be use. I know not the smartest question but worth asking.

Well... I would hope at 69 outside temp heat won't be running! Most Carriers have the chart on the inside of access panel. ANd that is good question on TXV outside... subcooling? Never thought of it.. just used charts.