After your new heat pump is physically installed, the installer doesn't simply switch it on and leave. A thorough post-installation commissioning test is carried out to confirm the system is safe, correctly set up, and performing to the manufacturer's specifications. Here's what that process involves and why each step matters.
Why Commissioning Matters
Commissioning is the final quality check between installation and handover. A heat pump that hasn't been properly commissioned may run inefficiently, fail prematurely, or — in rare cases — pose a safety risk. In New Zealand, installers are expected to follow manufacturer guidelines and relevant standards, and a good installer will provide you with a commissioning record as part of the job documentation.
Electrical Safety Checks
Before anything is powered up, the installer verifies the electrical supply. This includes:
- Confirming the dedicated circuit is correctly rated (voltage and amperage) for the unit
- Checking that earthing and wiring comply with the applicable NZ wiring rules and standards
- Inspecting the isolator switch is correctly positioned and labelled
- Testing that the unit powers on without tripping the circuit breaker
All electrical work on a heat pump installation is restricted electrical work under the Electricity (Safety) Regulations and must be carried out — and certified — by a registered electrician. You can verify your installer's registration with the Electrical Workers Registration Board.
Refrigerant and Pressure Checks
Refrigerant handling is a specialist task. The installer will:
- Check that the refrigerant lines (lineset) are correctly sized, insulated, and free of kinks
- Perform a vacuum test (evacuation) on the refrigerant circuit to remove moisture and non-condensables before charging
- Confirm the refrigerant charge is correct — either factory-charged or topped up to the manufacturer's specification for the pipe run length
- Check for leaks using an electronic leak detector or soap solution
Refrigerant work requires a refrigerant handling licence under the Ozone Layer Protection Act. Never attempt to handle refrigerant yourself.
Airflow and Drainage Checks
Proper airflow is critical to efficiency and longevity:
- The indoor unit is checked for correct mounting angle to ensure condensate drains freely
- The condensate drain is tested by pouring water into the tray and confirming it exits cleanly — a blocked drain can cause water damage and mould
- The outdoor unit clearances are confirmed: adequate space around the unit for airflow, and no obstructions that could cause short-cycling of air
- Filters are confirmed clean and correctly seated
For homes subject to the Healthy Homes Standards, landlords should note that heat pump placement and heating capacity requirements are specified — your installer should be aware of these if you're renting out the property.
Operating Mode Tests
The installer runs the unit through its operating modes:
| Test | What's Checked |
|---|---|
| Heating mode | Supply air temperature rise, thermostat response |
| Cooling mode | Supply air temperature drop, dehumidification |
| Fan-only mode | Airflow volume and noise levels |
| Auto mode | Correct mode switching based on set temperature |
The installer measures the temperature differential between the air entering the indoor unit (return air) and the air leaving it (supply air). A typical heating differential is around 8–15°C, though this varies by unit and conditions. If the differential is outside the expected range, it may indicate an incorrect refrigerant charge or airflow restriction.
Control and Remote Checks
- The remote control or Wi-Fi controller is paired and tested
- Timer and scheduling functions are confirmed working
- If a wired controller or home automation integration is fitted, each function is tested
- The installer should walk you through basic operation at handover
Noise and Vibration Inspection
The installer listens for any unusual noises — rattling, hissing, or gurgling — that could indicate loose components, refrigerant issues, or incorrect mounting. The outdoor unit is checked to ensure anti-vibration feet or brackets are correctly installed, particularly important on decks or lightweight structures.
Documentation and Handover
A professional installer will provide:
- A commissioning checklist or sign-off sheet
- The manufacturer's warranty card (often requiring registration)
- Guidance on filter cleaning intervals and basic maintenance
- A Certificate of Compliance (CoC) for the electrical work from the registered electrician
Keep these documents safe — you'll need them for warranty claims and potentially for future property sales.
When to Call a Professional
All heat pump installation and commissioning work should be carried out by a qualified, experienced installer. Refrigerant handling and electrical connections are both legally restricted in New Zealand. If you suspect your heat pump wasn't properly commissioned — for example, it's not heating or cooling effectively, making unusual noises, or leaking water — contact a qualified heat pump technician promptly. You can find licensed heat pump installers in your area at tradedirectory.co.nz.
For general guidance on energy-efficient heating choices, Energywise is a helpful NZ government resource.
Sources & Further Reading
- Electrical Workers Registration Board (EWRB) — verify your electrician's registration
- Energywise – Heat Pumps — NZ guidance on efficient heating
- Tenancy Services – Healthy Homes — heating standards for rental properties
- BRANZ — NZ building and construction research
- MBIE Building Performance — NZ Building Code information
- WorkSafe NZ — safety requirements for trade work
ISO 9001
