A single-room installation is typically a day's work for two people. Multi-room systems run longer, mostly because of pipe routing rather than the units themselves.
Most of that time goes into things that will be invisible afterwards: the route, the brackets, the electrical supply, and the pressure and vacuum work on the refrigerant pipework. Those invisible stages are exactly where installation quality lives.
The installation, stage by stage
- 1
Survey and design
Room-by-room cooling load, indoor unit format and position, outdoor unit siting, pipe route, condensate drainage and electrical supply all decided before quoting.
- 2
Positioning and marking
Indoor bracket set with clearances above and around it; outdoor position confirmed for airflow, service access and noise.
- 3
Core drilling
A wall penetration is drilled with a slight fall outward, dust-controlled, and sleeved and sealed once the pipework is through.
- 4
Pipe, cable and drain run
Insulated copper refrigerant lines, interconnecting cable and condensate drain run together, in trunking where the route is exposed.
- 5
Mounting both units
Indoor unit hung level on its bracket; outdoor unit on brackets, feet or a base pad with anti-vibration mounts.
- 6
Pressure test
The pipework is pressure tested with dry nitrogen to prove every flare and joint before any refrigerant enters the system.
- 7
Evacuation
A vacuum is pulled and held to remove air and moisture. Skipping or rushing this is the classic cause of premature compressor failure.
- 8
Charge and commission
Refrigerant released or weighed in per the pipe length, operation checked in cooling and heating, temperatures and pressures recorded.
- 9
Handover
Controls demonstrated, filter cleaning explained, and F-Gas and commissioning documentation provided.
Why the vacuum stage matters more than anything else
Air and moisture inside a refrigerant circuit are corrosive and destructive. Moisture reacts with the oil, forms acids, and attacks the compressor from the inside over months and years. The system will still cool beautifully on the day it is handed over, which is precisely why a rushed evacuation is such a common corner to cut.
A proper evacuation takes time and a gauge that proves the vacuum was held rather than simply reached. If you watch nothing else during an installation, watch whether that stage happens properly.
Signs of a well-executed installation
- Nitrogen pressure test carried out and results stated, before refrigerant is introduced
- Vacuum pulled and held, with the reading recorded rather than eyeballed
- Wall penetration sleeved and sealed weather-tight on both faces
- Condensate drain with continuous fall, or a proper pump where fall is impossible
- Outdoor unit level, on anti-vibration mounts, with clearance for airflow and servicing
- Refrigerant charge adjusted for the actual pipe run length, not left at factory volume
- F-Gas paperwork and a commissioning record handed over
What to prepare before the day
Clear the wall where the indoor unit is going and the ground or wall area at the outdoor position. Move furniture away from the drilling line and expect dust control sheeting. Decide in advance where trunking will run if the pipe route is exposed, because that is an aesthetic decision that belongs to you rather than the installer.
If the electrical supply needs a dedicated circuit, agree how and when that happens, so commissioning is not held up waiting on a spur.
Arrange an air conditioning survey
We design the system round the room loads, the pipe route and the outdoor position, and every install is pressure tested and evacuated before charging.
Installations are judged years later, by whether the compressor is still healthy and the wall below the indoor unit is still dry. Both of those are decided by the two hours nobody watches.