Heat Pump Not Heating in Woodside

Heat Pump Not Heating in Woodside

Woodside sits up in wooded Peninsula hills, and the deep-canyon parcels off Skyline run cooler and damper than the open, sunnier lots. That matters for heat pumps, because a coil tucked into a shaded, redwood-lined side of a property frosts over more readily on a cool, humid morning. A heat pump is built to handle that with a defrost cycle, but when the defrost control fails, the coil ices, the outdoor unit loses its heat source, and the house stops warming up.

These are large estate properties, and many run more than one independent system across the main house, a guest house, and sometimes a pool house. So a no-heat call here is usually one of two things: a single system failing somewhere on a larger property, or an iced coil on a unit placed in a cold, shaded pocket of the lot. The mild Peninsula climate means the equipment is never working beyond its range, which is why these calls almost always trace back to a specific component, not a system that can't keep up.

The long private driveways and wooded terrain also shape where the equipment sits and how the condensate drains, and that placement is part of the diagnosis. We trace the actual fault before quoting, and on most jobs the diagnostic fee credits toward the repair.

Common causes

Failed defrost control on a shaded coil. On a cool, damp Woodside morning the outdoor coil can frost, and the defrost board is supposed to reverse the cycle briefly to melt it off. When that board or its coil sensor fails, ice builds up, the coil can no longer pull heat from outside air, and heating collapses. We confirm the defrost cycle initiates and the sensor reads correctly, then replace the board if it isn't commanding defrost.

Outdoor coil iced over. A coil packed in ice on arrival usually points to a defrost fault, though a low refrigerant charge or a stuck fan can ice a coil too. Rather than just thawing it and leaving, we clear the ice and figure out why it formed in the first place. Treating the symptom without the cause means a callback within a week.

Stuck reversing valve. The reversing valve flips the system into heating mode. A failed solenoid or a valve stuck mid-stroke leaves the unit running in cooling or stalled, so it blows unheated air on that one system while others on the property are fine. We meter the solenoid and read line temperatures to confirm the valve actually shifted before replacing it.

Low refrigerant charge. When a heat pump runs short on refrigerant, heating capacity drops first, and the outdoor coil can frost over too. Instead of topping off, we locate the leak with electronic detection, repair it, and weigh in the exact charge. On these estates, usually only the affected system is low, so we isolate that unit.

Control board or zone fault on one system. With multiple systems and zoning across a large property, a drifting control board or a damper stuck closed can drop heat to one building or wing while the rest of the property stays warm. Board status gets read and damper actuators tested to identify the system that lost its call, rather than guessing at the equipment.

How we diagnose it

• We look at the outdoor unit first for ice on the coil, which points straight at defrost or charge as the culprit.
• We confirm the defrost board actually starts a cycle and that the coil sensor is reading correctly.
• We verify with line temperatures whether the reversing valve genuinely shifted into heating.
• Refrigerant pressures get compared against outdoor temperature to catch a low charge before it frosts the coil.
• On properties with more than one system, we map which unit or building is affected before touching the equipment.

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

Heat Pump Not Heating in Woodside: common questions

Nearby and related

Heat Pump Not Heating near Woodside: Portola Valley · Hillsborough · Menlo Park .

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