If it smells of burning, sparks or keeps tripping the power
Turn it off at the remote and at the switchboard, and leave it off. Don't open either unit or touch the wiring. Electrical repairs need a registered and licensed electrical worker, and the refrigerant inside is a job for a trained technician only.
Checks you can safely do before booking
The remote and the mode
Check the batteries and that it's set to Heat, not Dry or Auto. Mitsubishi Electric NZ recommends picking Heat or Cool by season, and points out the unit isn't heating at all in Dry mode.
Give it a few minutes
Once a room reaches the set temperature, Mitsubishi Electric NZ says the unit ramps down but keeps moving room air, which won't feel warm. In cold weather it also pauses heating for short spells to defrost the outdoor unit.
Try a power reset
Samsung NZ suggests a power reset before anything else. Switch it off at the isolating switch or switchboard, wait a minute, then turn it back on. If a switch at the board trips again, leave it off.
Look at the filters
Consumer NZ says the filters need regular cleaning to keep a heat pump working efficiently. Clean them the way your manual describes.
Check the outdoor unit
Clear leaves, plants and anything stacked against it. Mitsubishi Electric NZ says a unit squeezed against a wall without its clearances loses output, and one boxed in under a deck can create its own microclimate.
Write down any error code
Samsung NZ says to note the code, and that a blinking light on the indoor unit can also signal a fault. You'll need the model number from the label on the indoor unit to find the manual, and our error codes guide shows where brands keep theirs.
Common faults, and what's usually behind them
Blowing cool air on heat. Usually a defrost cycle, or a room that's already up to temperature. EECA says frosting starts once it's below 5.5 degrees outside. If it blows cool for long stretches on a mild day, that's one for a technician, and our not heating guide goes through it.
Can't keep up on the coldest nights. BRANZ says an undersized heat pump runs constantly trying to reach the set point, which can make the outdoor coil defrost again and again. That's a sizing problem, and no repair cures it.
Water inside. Nearly always the drain. Start with heat pump leaking water.
Rattling, grinding or a much louder hum. Samsung NZ says some fan noise is normal, especially at start-up, but loud or unusual noise means a professional clean or service. BRANZ links noisy outdoor units to worn bearings and parts that haven't been maintained.
A smell that won't go. Samsung NZ says persistent odours may need the indoor unit cleaned professionally. Our smells and noises guide has the steps to try first.
Who can repair a heat pump?
A heat pump repair specialist, or the business that installed or services your unit. Under warranty, start with them. Hitachi NZ sends repairs and warranty claims to the business that sold and installed the unit first, then to Temperzone. Rinnai NZ's warranty excludes damage from repairs by anyone other than its accredited installers, service people or service centres.
Repairs to the refrigerant circuit, like finding and sealing a leak, need someone who can buy refrigerant. That's an industry rule here, not a law: wholesalers may restrict sales to holders of an RLTB Refrigerant Licence or an EPA Approved Handler or Approved Filler test certificate.
Faults in the wiring or the supply are for a registered electrical worker. You can check their name and licence on the EWRB register, and a digital licence carries a QR code that opens their register profile.
Your rights when a heat pump fails
Your Consumer Guarantees Act rights don't depend on the warranty. A heat pump bought from a business must be of acceptable quality, which includes being durable and lasting a reasonable time. The business can't limit what it owes you to the maker's warranty terms.
If it falls short, the business can repair it, replace it or refund you, at no charge and within a reasonable time. Installation and repair work is covered separately. A service must be carried out with reasonable care and skill, and if it isn't, you can require the business to put it right within a reasonable time.
If you can't sort it out together, the Disputes Tribunal hears claims up to $60,000, including whether a tradesperson did the work properly and what they charged.
What you can check, and what needs a technician
You can
- Batteries, mode and set temperature on the remote.
- One power reset at the isolating switch or switchboard.
- Cleaning the filters as the manual says.
- Clearing the area around the outdoor unit.
- Noting any error code, when the fault happens and what the weather's doing.
Leave to a licensed installer
- Opening either unit or touching the wiring.
- Finding and fixing refrigerant leaks, and recharging the system.
- Replacing fans, sensors, circuit boards or valves.
- Clearing a blocked drain inside the unit.
What the repair quote should tell you
- What failed, and how they know.
- Whether it's a quote (a set figure that can't rise once you accept it, unless the job changes) or an estimate (a best guess).
- Whether there's a fee for the visit or diagnosis. Consumer Protection says a business that charges to prepare a quote has to tell you beforehand.
- Which parts the brand's warranty covers, and which it doesn't.
- If refrigerant was involved, where the leak was and how it was fixed.
- Whether any wiring work comes with a Certificate of Compliance.
What we'd do
Repair it or replace it? Our view
If it's under warranty, we'd go back to the installer or the brand before anyone else opens it up. Out of warranty, with one failed part on a unit that has always heated the room well, we'd usually repair. But if it has never kept up on cold nights, we'd stop spending on fixes and have it properly sized and replaced, because no repair makes a small heat pump bigger.