Heat Pump Not Heating in Half Moon Bay

Heat Pump Not Heating in Half Moon Bay

A heat pump that will not heat often comes down to the same reversing valve, only stuck in the other direction, or a defrost cycle that never completes and leaves the outdoor coil iced over. Low refrigerant, a failing outdoor fan motor, or a corroded contactor and capacitor can all shut heating down the same way they would shut down cooling. We check mode, defrost, and charge in that order before opening anything mechanical. The detail that matters in Half Moon Bay is the constant marine layer that limits real cooling days and the salt air that eats outdoor equipment.

Local climate and housing age both matter for a heat pump heating call. Half Moon Bay sits directly on the coast, and the marine layer is not an occasional visitor here, it is the default weather. Summer afternoons rarely climb out of the 60s, real cooling days are the exception, and heating is what actually keeps a house comfortable most of the year. Housing runs from the historic downtown core near Main Street to newer subdivisions up Highway 1 and along the ridge above town. Salt-laden coastal air reaches every outdoor unit here and corrodes coil fins, contactors, and cabinets faster than almost anywhere else we work.

In Half Moon Bay, we check mode, defrost, and refrigerant charge in that order, because a heat pump that won't heat is rarely one single obvious thing. Whatever the sequence turns up goes on a written estimate, and the $99 diagnostic fee is credited toward the repair.

Common causes

Corroded contactor or capacitor on the outdoor unit. The same electrical parts that fail on an AC condenser fail on a heat pump's outdoor unit. The salt-laden coastal air here corrodes contacts, terminals, and coils noticeably faster than an inland climate would. A failed capacitor or a pitted contactor keeps the outdoor unit from running at all.

Stuck reversing valve. A reversing valve stuck in cooling mode leaves the system unable to produce heat no matter what the thermostat calls for. It is one of the first things we rule in or out.

Low refrigerant from a corroded coil or fitting. A leak drops the charge low enough that the system cannot pull adequate heat from the outdoor air, and a corroded fitting is a common leak point. The salt-laden coastal air here corrodes contacts, terminals, and coils noticeably faster than an inland climate would.

Failed defrost control. In cold, damp conditions the outdoor coil ices over and the system has to periodically defrost it. A failed defrost board or sensor leaves the coil frozen solid, which blocks heat transfer entirely.

Seized or failing outdoor fan motor. Without the outdoor fan moving air across the coil, the system cannot pull heat from the outside air efficiently, and a seized motor is a common, testable failure.

How we diagnose it

• Confirm the thermostat is actually calling for heat and the system is in heat-pump mode, not stuck on emergency or off.
• Read line temperatures at the indoor and outdoor coils to tell whether the reversing valve has actually shifted into heating.
• Meter the capacitor and inspect the contactor for wear. The salt-laden coastal air here corrodes contacts, terminals, and coils noticeably faster than an inland climate would.
• Read refrigerant pressures against the outdoor temperature to spot a low charge before chasing the leak.
• Confirm the defrost board initiates a cycle and the outdoor coil is clear of ice.

$99 diagnostic, credited toward the repair. You get a written quote before any work begins.

Heat Pump Not Heating in Half Moon Bay: common questions

Nearby and related

Heat Pump Not Heating near Half Moon Bay: Pacifica · San Mateo · Burlingame .

This is usually a heat pump installation & service in Half Moon Bay job. See our heat pump installation & service overview or the Half Moon Bay service area.