HVAC SOP Example

Ductless Mini-Split Installation

Single-zone wall-mount mini-split installation with line set, drain, and startup commissioning.

1. Select mounting locations & plan line set routeSelect indoor air handler mounting location — minimum clearances: 6" from ceiling, 6" from side walls, no obstructions within 3 feet of air discharge. Confirm exterior wall has no plumbing, wiring, or structural members at planned penetration location. Locate outdoor unit mounting pad or wall bracket — ensure unit is level, has adequate clearance on all sides per manufacturer spec, and is accessible for service.
2. Mount indoor air handler & core exterior wallMount rear plate to wall using manufacturer template — ensure level and anchored to studs or with appropriate wall anchors. Core 3" hole through exterior wall at 3° downward slope toward exterior for proper condensate drainage. Run line set sleeve through core. Mount indoor unit body on rear plate. Verify unit is secure and level before proceeding.
3. Install outdoor unit & line setSet outdoor unit on concrete pad or wall bracket — verify level and all anchor fasteners are torqued per spec. Run pre-flared or field-flared line set from indoor to outdoor unit. Protect line set with appropriate UV-resistant line set cover or insulated sleeve on exposed exterior runs. Avoid sharp bends — maintain minimum bend radius of 4x tube diameter. Secure line set at maximum 24" intervals.
4. Electrical connectionsRun dedicated circuit per nameplate requirements from main panel — verify wire gauge matches breaker size and unit ampacity. Connect wiring at outdoor unit per wiring diagram — observe color code and polarity. Connect communication wire between indoor and outdoor units per manufacturer wiring diagram. Verify all terminals are tight and no wire insulation is damaged at any connection point.
5. Condensate drain & vacuumConnect and route indoor unit condensate drain to approved exterior termination point — maintain minimum 1/8" per foot slope throughout entire drain run. Test drain by pouring water into drain pan. Attach micron gauge to the system. Pull vacuum to below 500 microns — hold 15 minutes with service valves closed. Any vacuum rise indicates a refrigerant leak that must be found and repaired before charging.
6. Charge & startupIf system is pre-charged with sufficient line set length, open service valves. If additional refrigerant is required, add by weight per manufacturer charging chart for actual line set length. Power the unit. Set remote to cooling mode at 65°F setpoint. Verify compressor starts, indoor air flow is correct, and supply air temperature drops to expected range (typically 18–22°F below return air temp at design conditions). Verify heating mode operation. Record all startup readings.