Heat Pump Not Heating in Los Altos Hills, CA

Heat Pump Not Heating in Los Altos Hills

Los Altos Hills is large-lot estate housing on rolling foothill terrain, and the floor plans are big and spread out enough that a single system rarely covers a house evenly. Many of these homes run multiple air handlers and zoning, and because the equipment often sits a long way from the spaces it serves, the refrigerant line sets are long. That length matters when a heat pump stops heating. A long line set has more fittings, more places to leak, and a charge that has to be exactly right for the system to deliver full heating capacity.

The foothills run on the warmer, drier side, so the cooling side genuinely earns its keep here, but winters are mild and rarely freeze. A heat pump covers both without struggling against the climate. So when one of these systems quits heating, it is almost always a specific fault: a low charge on a long run, a stuck reversing valve, a failed contactor, or a zone that dropped out on a sprawling plan. It is rarely a system that cannot handle the weather.

The steep lots, the long line runs, and the spread-out plan are part of the diagnosis as much as the install. We trace the real fault before quoting, and the diagnostic fee credits toward the repair on most jobs.

Common causes

Low refrigerant on a long line set. These estates run long refrigerant lines from condenser to air handler, and every brazed joint and flare along that run is a potential leak. A heat pump short on charge loses heating capacity first and can frost the outdoor coil. We pressure-test, find the leak with electronic detection, repair it, and weigh in the correct charge for the actual line length rather than topping off to a generic number.

Stuck reversing valve. The reversing valve switches the system into heating, and a failed solenoid or a valve stuck mid-stroke leaves it running in cooling, blowing unheated air. On a multi-system house only the affected system goes cold. We meter the solenoid and read line temperatures to confirm the valve shifted before replacing it.

Zone dropped out on a spread-out plan. With several air handlers and zoning across a large footprint, a stuck-closed damper or a zone board fault can leave one wing cold while the rest of the house heats normally. We test the damper actuators and zone board outputs to find the zone that lost the call, then repair the actuator or board, not the equipment.

Contactor or capacitor failure. A failed contactor or weak start capacitor takes a whole condenser offline, so one system stops heating. These are common, low-cost failures we carry on the van. We meter the capacitor and inspect the contactor on the affected unit before doing anything more invasive.

Defrost control fault. Even in the mild foothills the outdoor coil can frost on a cold, damp morning, and a failed defrost board lets the ice build until heating drops off. We confirm the defrost cycle initiates and the coil sensor reads correctly, and replace the board if it is not commanding defrost.

How we diagnose it

We identify which air handler and zone lost heat so we are diagnosing the right system on a spread-out plan.
The charge gets pressure-tested against the actual line-set length, since a long run changes the target.
Line temperatures confirm whether the reversing valve shifted into heating.
Zone damper actuators and board outputs get tested to rule out a closed damper starving a wing.
We inspect the outdoor coil for ice and verify the defrost board is cycling.

$75 diagnostic, credited toward any repair over $200. You get a written quote before any work begins.

Heat Pump Not Heating in Los Altos Hills: common questions

Los Altos Hills is a haul from San Ramon. Do you actually come out here?

We do. We service the South Bay foothill estates and route these calls from our San Ramon base. A no-heat call gets priority and we do our best to come same day, though on a far-out estate we book a real window instead of promising one we cannot keep. Call (925) 999-4095.

My equipment is a long way from the house. Does that affect the heating problem?

It can. Long line sets carry more fittings, and the refrigerant charge has to match the line length to deliver full heating. When one of these systems quits, a slow leak on a long run is a common cause, and it is repairable. We charge to the actual line length, not a generic figure, and we note that on the estimate.

It cools fine in summer but won't heat in winter. How is that possible?

Heating and cooling use the same refrigerant loop but run it in opposite directions through the reversing valve. A valve that fails or sticks lets the system cool but not heat. A low charge also shows up as weak heating before it affects cooling. Both are specific, fixable faults, not a worn-out system.

Nearby and related

Heat Pump Not Heating near Los Altos Hills: Los Altos · Palo Alto · Mountain View · Cupertino .

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