Re-taping and weatherproofing your heat pump pipe bundle (also called the lineset cover or pipe chase) is one of the few heat pump maintenance tasks a homeowner can legally and safely tackle themselves. The pipes themselves carry refrigerant — which is restricted work — but the external insulation wrap and weatherproofing tape around the outside is fair game for a confident DIYer.
What Is the Pipe Bundle?
The pipe bundle running between your indoor and outdoor heat pump units typically contains:
- Refrigerant lines (copper pipes wrapped in foam insulation)
- Electrical control cable
- Condensate drain hose
All of these are bundled together and wrapped in UV-resistant tape or housed inside a plastic conduit/trunking. Over time — especially in NZ's harsh UV environment and coastal conditions — this tape degrades, cracks, and peels away, leaving the foam insulation exposed to the elements.
Why Weatherproofing Matters
Degraded wrapping causes real problems:
- Exposed foam insulation breaks down quickly in sunlight, reducing thermal efficiency
- Moisture ingress can cause condensation issues and corrosion on copper pipes
- Pests (especially wasps) love to nest in deteriorating foam
- In coastal areas, salt air accelerates corrosion if copper is left unprotected
Keeping the pipe bundle properly sealed helps your heat pump run efficiently and extends the life of the installation — important given that a quality heat pump is a significant investment.
What You'll Need
| Item | Notes |
|---|---|
| UV-resistant self-amalgamating tape or aluminium foil tape | Foil tape is excellent for UV resistance |
| Outdoor-rated pipe wrap tape (e.g. Denso or similar) | For extra weatherproofing in exposed locations |
| Replacement foam pipe insulation (if needed) | Match the diameter to your existing pipes |
| Sharp knife or scissors | For cutting tape cleanly |
| Isopropyl alcohol or surface cleaner | To clean surfaces before taping |
| Gloves and safety glasses | Basic PPE |
You'll find suitable tapes and foam insulation at Bunnings or Mitre 10. Ask staff for UV-stable outdoor pipe wrap tape.
Step-by-Step: Re-Taping the Pipe Bundle
1. Inspect Before You Start
Check the full length of the pipe run — from where it exits the wall to where it connects to the outdoor unit. Look for cracked foam, gaps in the wrap, and any signs of moisture or corrosion. If you see green corrosion on copper or damaged refrigerant line insulation that has compressed or split, stop and call a professional (see below).
2. Remove Old Tape
Carefully peel away all the old degraded tape. Don't yank hard — you don't want to damage the foam insulation or the pipes underneath. A plastic scraper can help.
3. Replace Damaged Foam Insulation
If sections of foam insulation are crumbling or compressed, cut them away and slide on replacement foam pipe insulation of the correct diameter. Secure joins with tape.
4. Clean the Surface
Wipe down the bundle with isopropyl alcohol and let it dry fully. Good adhesion depends on a clean, dry surface.
5. Apply New Tape
Wrap the bundle in a spiral pattern, overlapping each pass by at least half the tape width. Work from the bottom upward on vertical runs so water sheds off rather than under the tape. Keep the tape taut but not so tight it compresses the foam.
6. Seal the Ends
Pay particular attention to where the bundle enters the wall and where it connects to the outdoor unit. These entry points are common spots for moisture and pests. Use a UV-stable outdoor sealant or self-amalgamating tape to seal these junctions thoroughly.
7. Consider a Conduit Cover
For long exposed runs, consider fitting a plastic pipe conduit/trunking over the bundle. This gives long-term UV and physical protection and looks tidy. These snap-fit covers are available at most hardware stores.
What You Cannot Do Yourself
While the external weatherproofing is DIY territory, refrigerant work is legally restricted in New Zealand. Under the MBIE Building Performance framework and industry regulations, only certified technicians with the appropriate refrigerant handling certification may:
- Open, repair, or recharge refrigerant lines
- Connect or disconnect refrigerant fittings
- Handle refrigerants (which are subject to controls under NZ environmental and industry regulations — confirm current requirements with a certified technician)
If your pipe bundle has a refrigerant leak (signs include ice forming on pipes, reduced heating/cooling, or hissing sounds), do not attempt to fix this yourself. Contact a qualified heat pump installer.
Safety Note
Always turn your heat pump off at the isolator switch before working near the pipe bundle. While you're only working on the outside of the bundle, it's good practice. If you're working at height to reach a pipe run, use a stable ladder and have someone spot you. Check WorkSafe NZ guidance on safe ladder use.
When to Call a Professional
Call a qualified heat pump installer if you notice:
- Ice or frost forming on the refrigerant pipes
- Oily residue around pipe joints (possible refrigerant leak)
- Corroded or kinked copper pipes
- The pipe bundle has been physically damaged (e.g. by a lawnmower or vehicle)
- You're unsure about the condition of any component
A licensed installer can inspect the full system, carry out any restricted refrigerant work, and re-wrap the bundle to a professional standard. You can find qualified local heat pump installers on tradedirectory.co.nz.
ISO 9001
