- Refrigerant used up?
- No It runs in a sealed loop
- Needs a regas?
- Leak Find and fix it first
- Single-unit service
- $79–$249 Typical NZ range
"Your heat pump needs a regas" is one of the commonest lines in heat pump servicing, and one of the most misunderstood. Car air conditioning has trained a lot of people to think of refrigerant as something you top up every few years. A household split-system heat pump is different. Here's what low refrigerant actually means and what to ask before paying for gas.
Do heat pumps lose refrigerant over time?
A correctly installed heat pump shouldn't. The refrigerant is sealed inside the copper pipes and the two units, and it moves heat by changing between liquid and gas; nothing burns it off. If the charge is low, it has escaped somewhere: usually a flare joint at the indoor or outdoor unit that wasn't made up tightly at install, a pipe damaged by vibration or rubbing, or corrosion on the outdoor coil, which is more common close to the coast.
What are the signs a heat pump is low on gas?
- It runs, but the air from the indoor unit is only lukewarm on heat or barely cool on cool.
- It takes much longer than it used to to warm the room, and runs constantly.
- Ice or heavy frost on the outdoor unit's pipes outside normal defrost cycles, or frost on the indoor unit's pipe connections.
- An error code that the manual lists as low refrigerant or high discharge temperature.
- An oily mark at a pipe joint, which can be where refrigerant oil has escaped with the gas.
Should I just regas it?
Not without a leak test. Adding gas to a leaking system means paying for refrigerant that will leak out again, and releasing a greenhouse gas into the air while it does. The order a good technician follows is: confirm the charge is low, find the leak (with a detector, bubble solution or a pressure test), repair it, pull a vacuum to remove air and moisture, then recharge to the weight on the unit's label. If someone offers to "top it up" without mentioning a leak, ask why it's low.
How a heat pump leak should be repaired
- Confirm the symptom
Check filters, the outdoor coil and settings, then measure the system pressures against the maker's figures.
- Find the leak
Test the flare joints first, then the coils and pipe run, with an electronic detector or bubble solution.
- Repair it
Remake or replace the faulty flare, or repair the damaged pipe or coil.
- Vacuum the system
Pull a deep vacuum to remove air and moisture before any refrigerant goes back in.
- Recharge by weight
Charge to the amount on the unit's rating label, then check performance.
Is it worth fixing a leaking heat pump?
On a unit a few years old, usually yes: a remade flare joint is a small repair. The case for replacing gets stronger when the unit is over about 12 to 15 years old, the leak is in a corroded coil rather than a joint, or it has already been regassed once. Older units may also use R410A, while most new units use R32, which has a lower global warming potential; that's a reason to replace an old unit, not a reason to rush.
Who can regas a heat pump?
Only a technician trained and certified to handle refrigerants. Refrigerant gases are regulated because they're harmful when released, so this isn't a DIY job, and DIY top-up cans sold for car air conditioning are not suitable. If your unit is still under the maker's warranty, call the original installer first: a leaking flare joint in the first year or two is usually a workmanship issue for them to fix.
Frequently asked questions
How often does a heat pump need regassing?
Never, if it's sealed properly. Refrigerant isn't used up, so a heat pump that needs gas has a leak that should be found and repaired.
How do I know if my heat pump needs gas?
Weak heating or cooling, constant running, frost on the pipes outside normal defrost, an oily mark at a joint or a low-refrigerant error code. Rule out dirty filters first.
Can I regas my heat pump myself?
No. Refrigerant handling needs a certified technician and specialist equipment, and car air-con top-up cans are not suitable for a home heat pump.
Why does my heat pump keep losing gas?
Because the leak was never fixed. Common causes are a poorly made flare joint, a damaged pipe or a corroded coil. Ask for a leak test and repair before the next recharge.
Is a regas covered by warranty?
A leak in the first year or two is often an installation fault, so call the original installer first. Workmanship and manufacturer warranties differ, so check both.
Should I replace an old heat pump instead of regassing it?
Often, if it's 12 to 15 years old, the leak is in a corroded coil, or it's been regassed before. Newer units are usually more efficient and use R32 refrigerant.