Extending the refrigerant pipe run on an existing heat pump is not a DIY job in New Zealand — it is legally restricted work that must be carried out by a licensed refrigeration and air conditioning tradesperson. That said, understanding why, and knowing what you can do yourself, will help you plan the project and have a more informed conversation with a qualified installer.
Why Refrigerant Work Is Restricted in NZ
Refrigerant pipework is part of a sealed, pressurised system containing substances that can be harmful to people and the environment. Under New Zealand law, anyone who works on a refrigerant circuit — including cutting, joining, extending, pressure-testing, evacuating, or recharging — must hold the appropriate refrigerant handling licence issued under the Ozone Layer Protection Act 1996. This is enforced nationally, and there is no Schedule 1 exemption that allows homeowners to do this work themselves.
Beyond the legal requirement, there are strong practical reasons to use a professional:
- Refrigerant leaks can reduce system efficiency dramatically and, depending on the refrigerant type (commonly R32 or R410A in modern systems), pose flammability or health risks.
- Incorrect pipe sizing, excessive bends, or an overly long run can cause the compressor to work harder, shortening its life.
- Most manufacturer warranties are voided if the system is modified by an unlicensed person.
- The NZ Building Code may require a building consent for certain installation changes — always check with your local council.
What Does Extending a Pipe Run Actually Involve?
When a heat pump is installed, the refrigerant line set (a pair of insulated copper pipes carrying liquid and gas refrigerant) is sized and routed to match the specific distance between the indoor and outdoor units. Extending this run means:
- Recovering the existing refrigerant from the system using certified recovery equipment.
- Cutting and brazing or flaring the copper pipework to add the extra length.
- Pressure-testing the extended circuit with nitrogen to check for leaks.
- Evacuating (deep vacuum) the system to remove moisture and air.
- Recharging with the correct refrigerant type and quantity — which may need to be adjusted if the pipe run is significantly longer than the original design.
Each of these steps requires specialist tools and a valid refrigerant licence. WorkSafe NZ provides guidance on handling hazardous substances, including refrigerants.
Will My System Handle a Longer Pipe Run?
This is a critical question to ask your installer before proceeding. Every heat pump model has a maximum allowable pipe length and height difference between the indoor and outdoor units, specified by the manufacturer. Exceeding these limits can:
- Reduce heating and cooling capacity
- Cause oil return problems in the compressor
- Trigger fault codes or premature failure
Your installer will check the manufacturer's technical data sheet for your specific model. In some cases, a longer run may require an additional refrigerant charge (top-up), while in others the system simply cannot be extended beyond a certain point without replacing the outdoor unit with a more powerful model.
What Can a Homeowner Do?
While you cannot touch the refrigerant circuit, there are tasks you can legally do to prepare for the job:
- Plan the new pipe route and discuss it with your installer.
- Clear access along the proposed route (moving furniture, garden items, etc.).
- Chase or drill wall penetrations if you are comfortable doing so — though confirm with your installer first, as they may prefer to do this themselves to ensure correct sizing and sealing.
- Paint or finish any new pipe boxing once the installer has completed and signed off the work.
Note that any electrical work — such as extending or modifying the dedicated circuit to the outdoor unit — is also restricted work and must be done by a registered electrician. Check the Electrical Workers Registration Board (EWRB) to verify your electrician's registration.
Pipe Insulation and Boxing
Once the licensed installer has completed the refrigerant work, the pipes must be properly insulated to prevent condensation and heat loss. Closed-cell foam insulation (such as Armaflex or similar products) is standard. Exposed runs are often protected with UV-resistant pipe boxing or conduit. Your installer will typically handle insulation as part of the job, but finishing the boxing for aesthetics can be a homeowner task.
Cost Considerations
As a rough guide only, extending a refrigerant pipe run typically involves a call-out fee plus an hourly rate for the tradesperson, plus materials (copper pipe, fittings, insulation, and potentially additional refrigerant). The total cost will vary depending on the length of the extension, access difficulty, and whether electrical work is also needed. Get at least two quotes from qualified installers.
When to Call a Professional
You should call a licensed heat pump installer for any work that involves opening or modifying the refrigerant circuit. This includes extending pipe runs, relocating either unit, repairing leaks, or recharging the system. A good installer will also advise whether your existing system is suitable for the extended run or whether an upgrade makes more sense.
You can find qualified local heat pump installers on tradedirectory.co.nz. Look for installers who are members of the Air Conditioning and Refrigeration Association of New Zealand (ARANZ) or who hold a current refrigerant handling licence.
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