On Thu, 05 May 2011 16:16:20 -0400, Gogarty
wrote:

Without the mainifold
one just runs the pump for a log time, removes the pump and attaches the R34a
can to the port with an adapter. The adapter has a gauge on it and a trigger
for squirting in the refrigerant. The system would not be running.

Normal practice is to charge the system from the low pressure port
with the compressor running. Before attaching the adapter to the low
pressure port it is a good idea to shoot a small amount of coolant
through the hose to clear out any residual air and moisture.