E15 on a Haier heat pump is the anti-freeze fault, a protection code that appears when the system detects a risk of the water side freezing. It often clears once conditions improve, but if it keeps coming back, something is restricting flow or heat.
If E15 returns after one restart, book an engineer rather than resetting again. We carry out Haier heat pump repairs across the UK. For every other fault, see our full guide to Haier heat pump error codes.
Please read first: this guide is here to help you understand what your Haier heat pump is telling you. Every effort has been made to keep the information accurate, but manufacturers update their manuals and codes can differ between models and software versions, so always check the official Haier manual for changes before acting on anything here. Do not attempt anything that could be dangerous, and avoid any work that could void your warranty. If in doubt, call a qualified heat pump engineer.
What does E15 mean on a Haier heat pump?
Haier's manual lists E15 as an anti-freeze fault on the R290 Super Aqua Hydro Split and Hydro All in One. The unit confirms the fault after three occurrences within one hour, and the manual marks it as resumable, so it clears itself once the condition behind it goes away.
The manual gives the meaning only, not the cause. In general terms, an anti-freeze protection code tells you the water in the heat pump's heat exchanger is getting too cold for safe running, so the unit acts to stop it freezing. Other Haier models, including the Super Aqua monobloc, may use different codes, so check your own manual.
Is ice on a heat pump normal?
Some frost on the outdoor coil is normal in cold, damp weather, and the unit melts it off with regular defrosts. You may see steam and dripping water during a defrost, then the system goes back to heating.
E15 is a different matter, because it is a protection code rather than a normal part of defrosting. Ice that keeps building between defrosts, or a code that keeps returning, is a sign of a fault. Our guides to the heat pump defrost cycle and a heat pump frozen outside unit explain the difference.
Why does E15 appear in cold weather?
E15 appears in cold weather because that is when water in the system is most at risk of getting too cold, especially if flow is poor. Haier's manual gives no causes, so everything below is general engineering knowledge rather than Haier instructions.
- Low water flow. Sludge, a blocked strainer or magnetic filter, or a closed valve slows the water down, so it cools too much as it passes through the heat exchanger.
- Air locks. Trapped air reduces circulation and can leave parts of the circuit almost still.
- Low system pressure. A slow leak lowers flow and can bring on E08 alongside E15. See heat pump losing pressure.
- Scale or sludge on the plate heat exchanger. Deposits restrict flow through the part most at risk.
- An unheated or switched-off property. If heating is off for days in a frost, the water sits cold in the pipes and the unit.
- Failed defrost sensor or valve. Faulty defrost leaves the coil iced and the unit struggling for heat.
- Frozen or blocked condensate drain. Meltwater refreezes around the base and coil.
- Snow, leaves or a low position. Blocked airflow, or a unit sitting low in drifting snow, adds to icing.
- Low refrigerant. A leak cuts the unit's output and can show as low pressure codes E39-0 or E49.
If the heat pump stops altogether, our guide to air source heat pump not working covers the wider checks.
What can you safely check yourself?
You can make a few outside checks without tools, as long as you never open the unit. Work through these in order:
- Keep the power on. Frost protection needs power to run, so do not leave the heat pump switched off at the isolator in freezing weather.
- Clear around the unit. From outside the casing, brush snow, leaves and debris away from the front, back, top and underneath, by hand or with a soft brush.
- Check the condensate drain. Make sure meltwater can run away from the base. If the drain path is iced, thaw it with lukewarm water only, never boiling.
- Check the pressure gauge and valves. Look at the system pressure and confirm the isolation and radiator valves are open. Top up only if you have a filling loop and your manual allows it.
- Check your settings. If you are away, use a holiday or frost setting rather than switching off. Our guide to heat pump holiday settings explains how.
- Give it time, then restart once. Haier marks E15 as resumable, so it should clear on its own once conditions improve. If it does not, switch off at the isolator, wait a few minutes and switch straight back on, once only.
What not to do
- Never chip, scrape or prise ice off the coil or fan.
- Never use boiling water, a heat gun or a hairdryer on the coil.
- Never remove covers or touch wiring, boards or connectors inside the unit.
- Never touch the refrigerant circuit. Refrigerant work is restricted by law to certified engineers, and because Haier's R290 models use propane, a flammable refrigerant, the engineer also needs specific training for it.
When should you call an engineer?
Call an engineer if E15 keeps coming back on a normal winter day, or if it stays after one restart. Other clear triggers are:
- E15 showing alongside E08, which points to a flow problem that needs cleaning or bleeding.
- Low pressure codes E39-0 or E49, which point at the refrigerant side.
- Pressure on the gauge that keeps falling, or water where it should not be.
- Ice that stays on the coil for hours, or a fan that will not turn.
- No heating or hot water in a frost, especially with vulnerable people at home.
Any refrigerant work on an R290 Haier must be done by a certified engineer trained to handle flammable refrigerants. Our engineers are F-Gas certified and can diagnose the fault before any refrigerant work is needed.
How can you stop it happening again?
The best protection against E15 is good water flow and a unit that is serviced before winter. These points are general engineering advice rather than Haier instructions:
- Book an annual service. An engineer checks flow, pressure, the strainer, defrost and the coil. Our annual service checklist shows what is included.
- Keep the water clean. Clean the magnetic filter and strainer regularly. Older radiator circuits full of sludge may need a heat pump powerflush.
- Check frost protection. Make sure inhibitor, antifreeze or freeze-protection valves are in place where your installer fitted them, and never switch the system off for long in a frost.
- Insulate outdoor pipes. Lagging on the flow and return pipes reduces heat loss in the coldest weather.
- Lift and drain the unit. Raised feet or a stand, plus a clear drainage path, stop meltwater refreezing around the base.
- Choose a sensible spot. Keep the unit away from drifting snow, roof run-off and plants.
For more cold-weather habits, read our heat pump winter tips and our guide to running a heat pump in cold weather.
Other Haier codes you might see in a cold snap
A freezing spell can bring up other Haier codes alongside, or instead of, E15. Each code links to its entry in our Haier error code guide.
| Code | Haier meaning | Why it can show in cold weather |
|---|---|---|
| E87 | Defrosting with water temperature too low | Low flow or a very low setpoint |
| E08 | Flow switch fault or low water flow | Sludge, air lock or low pressure |
| E20-0, E20-1 | Outdoor defrost coil sensor fault | Failed sensor or damaged cable |
| E39-0, E49 | Low pressure protection and low pressure switch | Iced coil or refrigerant loss |
| E39-1 | Compression ratio too high | Iced coil or blocked circuit |
| E71-0, E71-1 | Upper or lower fan motor fault | Fan blocked by ice or debris |
Need help with a frozen Haier heat pump?
We repair Haier heat pumps across the UK, including the Super Aqua range. Our F-Gas certified engineers deal with E15, flow problems, defrost faults and refrigerant leaks, and we are MCS accredited. If your home is cold, our emergency heat pump repair team offers same-day visits where possible.
We find the cause first, then carry out the heat pump repair it needs, backed by a 12-month guarantee. To keep E15 away next winter, book annual heat pump servicing or spread the cost with one of our cover plans.
Call 0333 041 5130 or contact us online.
Frequently asked questions
Does E15 mean the heat exchanger has frozen and cracked?
Not usually. Anti-freeze protection is there to act before freezing does any damage. If you see water leaking from the unit or pipework after a frost, call an engineer to check for a split.
Why does E15 tend to show overnight?
Overnight is usually the coldest part of the day, and many homes turn the heating down or off at night. Less heat demand means slower, colder water in the circuit, which is when a flow problem shows up.
Should I turn the heating up to stop E15?
Turning the thermostat up will not fix a restricted flow or a blocked strainer. Keep your normal settings, keep the power on and get the flow checked if the code keeps returning.
Is an R290 heat pump safe to have outside my home?
Yes, R290 units are designed and certified for this refrigerant, and the circuit is sealed. The main rule is that only a suitably trained engineer should ever open the refrigerant side.
Does freeze damage count under my warranty?
That depends on your warranty terms and whether the unit has been serviced as required. Keep your service records and installation paperwork, and check the terms before anyone works on the unit.
