Burning smell, sparks or a switch that keeps tripping
Turn it off at the remote and at the switchboard, then leave it off. Don't take the covers off either unit. Wiring faults are for a registered electrical worker, and anything involving refrigerant belongs to a trained technician.
What Christchurch weather does to heat pumps
Cold snaps expose weak units
Christchurch has recorded an air temperature of -7.2 degrees and a grass minimum of -14.9 (NIWA). Rinnai NZ says it can't promise heating performance below zero, and Mitsubishi Electric NZ says a 5.6 kW unit gives about 4.76 kW at 0 degrees. A heat pump that copes in May and gives up in a July cold snap may be undersized rather than faulty.
Defrost on frosty mornings
NIWA averages 19 ground frosts in a Christchurch July. On those mornings the outdoor unit stops heating now and then to melt ice off its coil, and Mitsubishi Electric NZ says that's normal. With July's 9 am humidity at 88%, there's plenty of moisture to freeze on it.
Units boxed in under decks
Mitsubishi Electric NZ says outdoor units under houses, decking or anywhere airflow is impeded can create their own microclimate, and that a unit jammed against a wall without its clearances loses output. If a unit struggles every frost, its spot may be the real fault.
Salt damage near the coast
Within 500 m of the sea or the harbour, homes sit in NZS 3604's Zone D. Several warranties exclude corrosion: LG's NZ warranty excludes coil damage from corrosive air, Samsung's excludes salt spray, and Rinnai NZ makes owners in sea air responsible for extra protection. A corroded coil by the beach may not be a warranty job.
Snow and hail, now and then
Christchurch Airport averages 3 days of snow and 6 of hail a year (NIWA). After a fall, sweep snow away from the outdoor unit without touching the fins, and leave any damage to a technician.
Who to call, and in what order
Under warranty, start with whoever installed it. Hitachi NZ, for example, sends repairs and warranty claims to the business that sold and installed the unit, then to Temperzone Customer Care. Rinnai NZ's warranty excludes damage from repairs by anyone outside its accredited network.
Out of warranty, a heat pump repair specialist will diagnose it. Wiring or supply faults need a registered electrical worker, and anyone opening the refrigerant circuit must be able to buy refrigerant, which here rests on an industry arrangement the Commerce Commission authorised in 2011, not a licensing law.
Our national heat pump repairs page has the full set of safe checks, and heat pumps in Christchurch covers sizing and placement for a replacement.
Checks before you book, and what to leave alone
You can
- Make sure the remote says Heat, not Dry or Auto, and the batteries work.
- On a frosty morning, give it a few minutes to finish defrosting before deciding it's broken.
- Clear leaves, snow or firewood from around the outdoor unit.
- Note any error code and the model number on the indoor unit's label.
Leave to a licensed installer
- Opening either unit, or anything behind a cover.
- Refrigerant leaks and recharging.
- Fans, sensors, circuit boards and valves.
- Corrosion repairs to coils and casings.
Ask the repairer
- What failed, and how did you confirm it?
- Is this a quote or an estimate, and is there a fee for the diagnosis?
- Is the fault covered by the brand's warranty, or excluded as corrosion?
- Would a bigger unit solve this better than a repair?
What we'd do
Repair or replace? Where we land in Christchurch
If the unit has heated the room well for years and one part has failed, we'd repair it. If it has never kept up on frosty nights, we'd stop paying for fixes and get it resized, because no repair adds capacity at 0 degrees. Near the coast, we'd ask the repairer to check the outdoor coil for corrosion while they're there, since salt damage builds up quietly.