Braemar MCMX VRF — Refrigerant Reclaim / Vacuum (Pump‑Down) Mode

Purpose

Safety & Compliance

• Only qualified, licensed refrigeration technicians may perform refrigerant recovery. The Australian Greenhouse Office regulations apply; failure to comply can result in environmental harm and substantial fines.
• Do not vent refrigerant to atmosphere under any circumstances. Use an appropriate recovery unit, cylinders, and follow local laws.
• Isolate mains power at an approved isolator before disconnecting gauges/hoses and before beginning mechanical disconnections.

Overview of Options

Option 1 — Operational Pump‑Down via Cooling Run

1. Ensure the system is operational and the compressor can run.
2. Command all indoor units (IDUs) to Cooling at the lowest set temperature; allow the system to reach steady operation.
3. When stable, turn off power at the outdoor unit isolator. This ensures all valves remain open while power is off, allowing full system recovery with your reclaim unit. (Technician practice; aligns with intent of opening EXVs to enable recovery).

Option 2 — Use Outdoor PCB Function A8: Vacuum / Pump‑Down Mode

A) 4‑Button MCMX Outdoor PCB

1. Ensure the system is in Standby (power on, unit off).
2. On the outdoor MCMX PCB, press and hold SW1 for ~5 seconds to enter Function Settings.
3. Use SW1 (Up) and SW2 (Down) to scroll until LED1 displays A8.
4. Press SW3 (OK) to enter A8.
5. Select 01 — Vacuum / Pump‑Down Mode on LED2, then press SW3 to confirm. This opens all EXVs in the system for recovery.
6. Turn power off at the isolator and perform the reclaim process with approved equipment.
7. After recovery, restore power; the system resets to Off/Standby and returns to normal operation. (Function codes and Vacuum/Pump‑Down are documented in the Outdoor Function Setting and Error/Service code sections — see pages 28–31 of the manual.)

B) 7‑Button MCMX Outdoor PCB (older models)

1. Ensure the system is in Standby (power on, unit off).
2. On the outdoor MCMX PCB, press SW3 (Function) to enter Parameters / Function Settings.
3. Use SW1 (Up) or SW2 (Down) to scroll until A8 (Vacuum / Pump‑Down) is displayed.
4. Press SW7 (OK) to confirm. The system opens all EXVs for recovery.
5. Turn power off and complete the reclaim process.
6. Restore power; the unit resets to Off/Standby for normal operation. (Function access and service modes are per the manual’s function setting and service code listings — see pages 28–31.)

Notes & Supporting Manual References

• Function Setting of Outdoor Unit: Pages 28–31 detail how to enter function codes via SW buttons (including A‑series codes) and list special service functions.
• Service/Diagnostic Code Tables: Pages 24–27 include “Vacuum pump mode” and “Refrigerant recovery operation (after‑sales)”, confirming these functions.
• Removal & Disposal: Pages 36–37 reiterate that refrigerant must be recovered to a suitable container and never vented.

Technician Checklist (Quick Reference)

• Verify technician licensing and recovery equipment.
• Confirm standby state and PCB button layout (4‑button vs 7‑button).
• If using Option 1, run all IDUs in cooling to steady state, then power off to hold valves open.
• If using Option 2, enter A8 → 01 Vacuum / Pump‑Down via PCB, confirm, then power off for recovery.
• Connect reclaim unit; recover the full charge into approved cylinders.
• Leak‑test/repair as necessary; evacuate per standards (≥ 100 µPa vacuum as per install guidance — see page 10).
• Restore power; verify normal Off/Standby state.

Troubleshooting

• Cannot enter function mode: Ensure the unit is powered and in Off/Standby, and that compressor preheat requirements and debugging are complete if recently installed or after board replacement (see pages 20–23).
• EXVs not opening / recovery slow: Confirm A8 is selected and confirmed; check for communication or component errors and resolve per error code references (pages 24–27) before retrying.
• Regulatory queries: Refer to national/local refrigerant handling rules and the manual’s compliance warnings (pages 4–5).

Related Articles & Manual Page References

• Outdoor PCB Function Map & Button Guide (A‑codes): Pages 28–31
• Debugging Flow (SW7 long‑press sequence) and Address Allocation: Pages 20–23
• Refrigerant Charging by Pipe Length (Liquid line add‑on kg/m): Pages 18–19

Quick Guide 

1. If system works normally: Turn all indoor units ON in cooling at lowest temp → wait until running → switch OFF power at outdoor isolator → reclaim refrigerant.
2. If using PCB mode:
   • 4‑Button PCB: Power ON, unit OFF → hold SW1 for 5 sec → scroll to A8 → press SW3 → select 01 → press SW3 → turn power OFF → reclaim.
   • 7‑Button PCB: Power ON, unit OFF → press SW3 → scroll to A8 → press SW7 → turn power OFF → reclaim.