Symptom
Heat pump iced up or stuck in defrost?
In cold, damp weather a heat pump's outdoor coil collects frost, and the system runs a defrost cycle to melt it — steam and a few minutes of cooler indoor air are normal. A unit covered in solid ice, or one that seems to defrost constantly, usually has a defrost control, sensor, airflow or refrigerant problem and needs service.
Soon. A heavily iced unit can't heat properly and may be damaged if left. Schedule service promptly; call if the house is getting cold.
What usually causes this.
These are the common possibilities, not a diagnosis. A page cannot tell which one it is — that takes a technician testing the system.
- Outdoor unit
- Refrigerant lines
- Defrost control or sensor failure
- The board or sensor that starts defrost fails, so frost builds into ice.
- Outdoor fan problem
- A fan that doesn't stop and restart correctly during defrost can prevent ice from clearing.
- Low refrigerant charge
- Low charge makes the outdoor coil run colder and ice faster.
- Water dripping onto the unit
- A gutter or roof edge dripping onto the unit can freeze on top of it.
- Blocked coil or poor drainage
- Debris, snow or a unit sitting too low can trap meltwater, which refreezes.
What you can safely check.
- Watch for about an hour. A normal defrost clears the frost within minutes.
- Clear snow, leaves and debris from around and under the unit.
- Check whether a gutter or roof edge drips onto the unit.
Leave these alone
- Chipping, scraping or hitting ice off the coil.
- Pouring boiling water on the unit or forcing a defrost with the controls.
Call rather than book online if:
- The unit is encased in ice and the house is losing heat
- The fan is hitting ice or making a grinding noise
What we check when we get there.
In order, and every time — the point of a diagnostic is to find out which cause it is before anything is replaced.
- 01The technician tests the defrost board, sensors, reversing valve and outdoor fan operation, and checks the refrigerant charge.
What it is likely to cost.
A defrost board or sensor is a mid-range repair. A refrigerant leak costs more. You'll know the price before work begins.
- Diagnostic
- $89
- Defrost control board
- From $349
- Outdoor fan motor
- From $449
- Refrigerant leak / recharge
- From $499
Prices are starting points for standard work in the Savannah area. Final price depends on the system and site, and is confirmed before work begins. Permits and code-required upgrades may be additional.
Questions people ask about this.
- Is steam from my heat pump normal?
- Yes. During defrost the outdoor unit heats its coil to melt frost, and the melting frost gives off steam. It usually lasts a few minutes.
- Why is cool air coming from the vents in winter?
- Almost certainly a defrost cycle. The system briefly reverses to clear frost. Repeated or very long defrost cycles aren't normal.
Work out the decision:Seasonal Checklist
Further reading:Heat pump or gas furnace on the Georgia coast?
The service that fixes it.
Heat Pump Service & Installation is the work behind this symptom. Its page covers what is involved, how it is quoted and what we stand behind.
Symptoms that sit next to it.
Systems rarely fail in one way only. If one of these is also true, say so when you book — it narrows the diagnosis before anyone arrives.
Furnace or heat pump not heating, blowing cold air, cycling or running up the bill.
- Furnace won't turn on or lightA gas furnace that won't light is most often a worn igniter, a dirty flame sensor, a clogged filter tripping a safety limit, or a thermostat or power problem.
- Furnace blowing cold airA furnace blowing cold air is often a thermostat set to fan On rather than Auto, a furnace that has shut its burners off on a safety limit, or an ignition problem.
- Furnace turning on and offA furnace that runs for a few minutes, shuts off and restarts over and over is short cycling.
- Heat pump not heatingA heat pump that runs but doesn't heat well may have a thermostat set incorrectly, a dirty filter, an iced-up outdoor coil, a low refrigerant charge, or a reversing valve or defrost problem.
- Aux heat always on / high winter billAuxiliary heat is the backup — usually electric resistance — that helps a heat pump in very cold weather or during defrost.
Not sure which it is?Describe it to the assistant
Everything else we are called about.
The whole index, in three groups.
HUMIDITY, AIRFLOW & ENERGY BILLS
House feels humid or dampSome rooms too hot or coldPower bill suddenly higher
Get it looked at.
We cover Savannah, the Coastal Empire and the South Carolina Lowcountry. Tell us what the system is doing — you do not need to know the cause. The diagnostic price is given to you before the visit, and the repair price before any work starts.
No heat, or no cooling at all?Call rather than send a request — (912) 858-3737 is answered around the clock.