Since the liquid going in is what pushes the old liquid out, I would recommend first filling the machine with water so water is pushed through the system. Then you can disconnect the machine, disassemble the parts, and only water is spilling out on the ground. After that you can push new coolant in.
The waste coolant cannot be included in the replacement cycle. You can pump the coolant back into the vehicle (from the waste tank) but you would need to bleed the air out.
Since the liquid going in is what pushes the old liquid out, I would recommend first filling the machine with water so water is pushed through the system. Then you can disconnect the machine, disassemble the parts, and only water is spilling out on the ground. After that you can push new coolant in.
Can the coolant be recovered without adding new coolant so I can make any repairs to vehicle ie.water pump etc.
The waste coolant cannot be included in the replacement cycle. You can pump the coolant back into the vehicle (from the waste tank) but you would need to bleed the air out.