How do I pump all the refrigerant into the outdoor unit (pump down)?

Tools: Gauges, hex key for the service valves, wrench for the caps

1. Why: lock all the refrigerant in the outdoor unit (condenser + liquid line) so you can open the line set or the indoor unit without recovery. The refrigerant goes into the condenser, not into the compressor; the compressor only moves it there.
2. The unit runs in COOLING. A heat pump too — cooling only: in heating the flow is reversed and the refrigerant would go to the indoor unit.
3. Gauge on the suction port (large line). Take the cap off the liquid valve (small line) and turn it clockwise with the hex key until it stops (front-seat). No force: it stops — you stop.
4. The compressor moves the refrigerant from the line and evaporator into the condenser; suction drops. Keep your eyes on the gauge.
5. When suction gets to 0 psig but has NOT gone into a vacuum, front-seat the suction valve (large line) and immediately kill the unit at the disconnect.
6. NEVER pump a scroll compressor into a vacuum or run it in a vacuum: in a vacuum an arc can jump at the terminals and damage them. Many Copeland scrolls have internal protection that stops pumping at about a 10:1 pressure ratio, but don't rely on it.
7. Check: after shutdown suction stays near zero. If it climbs fast, the liquid valve or the compressor valves are leaking — recover the refrigerant with a recovery machine instead.
8. Mini-split: same order — small valve first, then the large one, in forced cooling mode (Test Run / Forced Cooling — per the model's manual). Disconnect the pipes only with the compressor off.
9. Going back: if the line set or indoor unit was opened — first evacuate to 500 µ with a decay test, then open both valves counterclockwise until they stop (back-seat). Caps back on: finger tight + 1/6 turn with a wrench.

Tools: Gauges, clamp meter

1. Signs: the compressor runs and hums evenly, amps well BELOW RLA, suction high, head low — pressures converge toward the middle. Small delta T, air barely cool.
2. Make sure it isn't low charge (high superheat and both pressures low there) or a stuck-open TXV.
3. Don't front-seat the suction valve or pull the compressor into a vacuum — it damages scrolls (internal arcing at the terminals). Instead compare amps with the manufacturer's table for these pressures and voltage. High suction + low head + amps well below expected → the compressor isn't pumping. On a heat pump rule out a leaking reversing valve first.
4. Shut off and watch: pressures equalize in seconds — valves/scroll check valve leaking (normal is minutes).
5. Megger/ohm the windings: C–S, C–R, S–R present and small; to ground — very high (Copeland: not below 0.5 MΩ on a scroll; never megger under vacuum).