[pressordrop1]

I agee with the load but you can do a delta t and if its between 18°&20° your charge should be good. With out a chart for charging from your manufactur that deals with low ambi temps you wont know for sure. If a unit is charged properly it should maintain a 20° split even in low ambient temps and I do not mean lower then 65° if its lower then that this method will not work and adding will over charge the system . It is best to wait until you have a load to work with . This is just to give you a idea if you are ok it is not a way to charge the system .

 

[pressordrop1]

I agree with adding load inside the building. I carry a fan cycling control with 2 alligator leads attached to the terminals and a flare tee with the control connected to the branch of the tee. Put the tee in series between my high side hose and a short hose to connect to the system high side. Disconnect the fan lead and clip in my fan cycling control. This allows you to run up the head pressure without having to carry a blanket or sheets of cardboard.

the fan cycling control doe it work on all refrigerants, is the pressure adjustable on it or does it stay at one pressure, tell me more Doc.

 

[pressordrop1]

I am making a low ambi temp charging tool out of a trane heat pump control board and im going to make it work with just a few leads and attachments . it tells me if the charge is good with the color lights , and i can charg it with that board to . IQ board .

 

[pressordrop1]

Remeber yor laws increas pressure increase the temp it should increase your SC