Heat Pump Not Heating in Menlo Park, CA

Heat Pump Not Heating in Menlo Park

A heat pump that stops heating is rarely a dead system. It is a refrigeration circuit running in reverse, and when the heat disappears the cause is almost always a single component. A reversing valve stuck in cooling. A defrost board leaving the coil iced. A low refrigerant charge. A contactor that won't close. The compressor and coils, the parts that would make replacement the better call, usually check out fine.

Menlo Park has some of the mildest weather in the Bay Area, with strong marine influence and winters that stay well inside heat pump range. A heat pump barely has to work to hold a comfortable house here, so when one falls behind on a normal winter morning, the climate is not the explanation. There is a fault to find. The mild climate also means a lot of Menlo Park systems are sized small and run light, which makes a single failed part more noticeable when it happens.

The housing runs the full range, from larger custom homes on the west side to older ranches and newer downtown infill. Some run ducted heat pumps, some run ductless mini-splits added during a retrofit. We confirm what you have, trace the fault to the part, and put the repair and the cost on a written estimate before we start.

Common causes

Reversing valve stuck in cooling. The reversing valve is what flips a heat pump into heating mode. When it hangs or its solenoid coil fails, the unit keeps running in cooling and blows cool air. We read temperatures across the valve and test the coil. A failed coil is inexpensive; a stuck valve body is a brazed repair we quote before doing it.

Low refrigerant charge. Even in mild Menlo Park, a slow leak drops capacity until the unit runs long and makes weak heat. We gauge the system, check it against spec, find the leak, repair it, and recharge. Topping off without sealing the leak just delays the same service call.

Defrost control fault. Marine air brings damp mornings, and the outdoor coil frosts. A healthy heat pump clears it on a defrost cycle; a bad sensor or board leaves the coil iced and unable to absorb heat. We watch a defrost cycle and confirm the sensor and board are timing and terminating correctly.

Failed contactor or capacitor. A pitted contactor or weak run capacitor leaves the outdoor unit silent or humming, so the compressor never starts and no heat moves. These are fast to meter and stocked on our truck, usually a same-visit fix.

Oversized system short-cycling. Because heating loads in Menlo Park are light, oversized equipment is a common local mistake. An oversized heat pump satisfies the thermostat in short bursts, never settles into an efficient cycle, and can feel like it is not really heating. We confirm sizing against the actual load and flag it if the equipment was spec'd by tonnage rather than a load calculation.

Mini-split fault on a retrofit. Homes with poor or no ductwork were often retrofitted with ductless mini-splits. When one stops heating it is usually a sensor, an outdoor board, or a communication fault between head and condenser. These report error codes, which we read and verify against the manufacturer's chart.

How we diagnose it

Confirm the system type, ducted or ductless, and that the thermostat is calling for heat.
Read line temperatures across the reversing valve to verify the unit is in heating mode, not stuck in cooling.
Gauge the refrigerant charge against spec and leak-check if it reads low.
Inspect the outdoor coil for ice and watch a defrost cycle.
Check sizing against the actual load when short-cycling is the complaint, and meter the contactor and capacitor.

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

Heat Pump Not Heating in Menlo Park: common questions

Are you actually covering Menlo Park from the East Bay?

Yes. We are based in San Ramon and service the full Bay Area, Menlo Park included. Peninsula calls are scheduled around bridge and 101 traffic so the arrival window we give you is realistic. Call (925) 999-4095.

Given how mild Menlo Park is, was my heat pump maybe oversized to begin with?

It happens here more than you would think. With heating loads this low, equipment sized by square footage instead of a real load calculation ends up too big, short-cycles, and never feels like it is heating steadily. If that is what we find, we will say so plainly rather than sell you a bigger replacement.

The heat pump turns on but the air is cool. Is the system finished?

Usually not. Cool air from a running unit points to a reversing valve stuck in cooling, a low charge, or an iced coil from a defrost fault, all component repairs. The $75 diagnostic tells you which one, and it is credited toward any repair over $200.

Nearby and related

Heat Pump Not Heating near Menlo Park: Palo Alto · Los Altos .

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