Heat Pump Repair on the Malibu Coast

Your heat pump is running, but the air from the vents feels cool, and the house in Malibu is getting colder by the hour. That call comes in on winter nights along PCH and up the canyons. The cause is often something small, and a diagnosis on the first visit usually finds it.

Heat pump not heating: the usual causes

Start with the simple checks. They take two minutes and save a service call when they work.

• The thermostat is set to heat, not cool or off, and the setpoint is above the room reading.
• The breaker for the indoor unit and the outdoor unit are both on.
• The air filter is not packed with dust. A blocked filter chokes airflow and the system trips on safety limits.
• The outdoor unit is not buried in leaves, debris or windblown canyon dust.

If those are fine, the fault is likely inside the system. A weak capacitor, a failing contactor, a stuck fan motor or a low refrigerant charge can each leave you with a unit that runs but does not heat. We measure refrigerant pressure, electrical draw and airflow on site, so the diagnosis comes from readings, not guesses.

Defrost cycles and what is normal

In heating mode the outdoor coil gets cold and can frost over. The system handles this with a defrost cycle. For a few minutes the unit reverses, the outdoor fan stops and you may see steam or a small cloud rising from the coil. Cool air may come from the vents during that short window.

That is normal. These signs are not:

• The coil stays iced over and the unit never clears it.
• Defrost runs again and again with little heating in between.
• Water pours out and refreezes at the base of the unit.
• A loud bang, grinding or buzzing starts when the unit switches modes.

If you see any of those, switch the system off at the thermostat and let it sit. Running a frozen heat pump can harm the compressor, which is the costliest part to replace.

Tell us the model, what the unit is doing and when it started. A short photo of the nameplate and the outdoor coil helps us bring the right parts on the first trip.

Salt air and the outdoor coil

Malibu air carries salt, and salt eats exposed metal. Outdoor coils, fan motors, wiring terminals and the unit cabinet all take the hit, especially on homes along the beach strip and on bluffs. Corroded fins block airflow. Corroded terminals cause intermittent faults that come and go, which makes them hard to chase without testing.

What helps:

• Rinse the outdoor coil gently with fresh water from a hose, with the power off. Never use a pressure washer.
• Keep plants and fences clear of the unit so air moves freely.
• Ask for a coil and electrical check at a heating maintenance visit before the cold season.

Canyon homes see dust on the coil and in the filter instead. We check salt damage and dust buildup on every coastal and hillside call.

Reversing valve, sensors and boards

The reversing valve is what lets a heat pump switch between cooling and heating. When it sticks, the unit may cool when you ask for heat, or it may heat poorly. A stuck valve can come from a failing solenoid, a wiring fault or a mechanical problem inside the valve. We test the coil and the control signal before we decide whether it is a small fix or a larger one.

Sensors and boards cause their own trouble. A bad outdoor sensor can tell the control board the coil is warm when it is frozen, so defrost never starts. A damaged board can lock out the system or send the wrong signal to the fan. These faults are easy to miss without a meter, and guessing at parts gets expensive fast. We read the fault codes first, then confirm each part with a test.

If you run a ductless mini split, the same logic applies. Each indoor head has its own sensors and fan, so a single room can fail while the rest of the house stays warm. Tell us which room, and whether the indoor head shows a blinking light.

Refrigerant leaks and A2L refrigerants on newer units

Heat pumps do not use up refrigerant. If the charge is low, there is a leak somewhere. Topping off without finding the leak only buys a short delay. We find the leak, explain the repair and write the estimate before work starts.

Refrigerant type matters too. R-22 is no longer produced, so repairs on older R-22 systems depend on reclaimed supply. Since the start of 2025, new residential split AC and heat pump systems are made with lower-GWP A2L refrigerants such as R-454B or R-32. Those refrigerants need the right tools and handling, so tell us the model when you call and we will plan the visit around it.

For an older system with repeated failures, we will say plainly if repair no longer makes sense. We only bring up replacement when the numbers point that way, and repair callers are always welcome. A new system is permitted work in California, and the city's building and safety division issues the permit.

FAQ

Why is my heat pump blowing cool air in heating mode?

It may be in a defrost cycle, which is normal and lasts a few minutes. If the cool air continues, the cause can be low refrigerant, a stuck reversing valve, a dirty filter or a failed outdoor part.

Is steam from the outdoor unit a problem?

Not usually. Steam rises when the coil defrosts and warm refrigerant meets cold, wet metal. Call if the coil stays frozen or the unit shuts off and will not restart.

Can salt air really damage a heat pump?

Yes. Salt corrodes fins, terminals and cabinet metal, and it shortens the life of outdoor parts. Regular rinsing and a yearly check slow the damage.

Should I keep running a heat pump that sounds wrong?

No. Turn it off at the thermostat and call. Grinding, banging or a frozen coil can turn a small repair into a compressor failure.

Do you repair ductless heat pumps?

Yes. We service ductless mini split systems in Malibu and the canyons, including single rooms that stop heating while the others work.

Call to book

A heat pump that is not heating does not fix itself, and the cold nights do not wait. Call (877) 352-4408 to book a repair visit with Malibu Coast AC Repair.