Heat Pump Not Heating in Albany
Albany leans on heat pumps for heat almost exclusively, since central AC barely exists in this marine-layer climate. Most of what we service here is ductless mini-splits, added to the compact bungalows on the Marin Avenue grid, to ADUs and basement units, and to family housing in UC Village along Buchanan Street, none of which had ductwork to begin with. When one of these heads stops putting out heat, the house cools fast in a small footprint, since there's no backup furnace running behind it.
A heat pump works by pulling warmth out of the outside air and pushing it into the house. On a foggy Albany morning the outdoor coil collects frost, and the unit runs a defrost cycle to clear it. When the defrost sensor or board goes bad, frost keeps accumulating on the coil until the system can't pull any more heat out of the air. That's the most common reason a mini-split here stops heating: the fog feeds frost, and a defrost fault stops the unit from shedding it.
It's almost always one part. A coil sensor that drifted. A defrost board that quit. A low charge from a small leak at a flare fitting in a tight installation. Albany winters rarely touch freezing, so the equipment isn't being pushed past its design limits. We track down exactly which part failed and get the repair in writing before touching anything.
Common causes
Defrost sensor or board fault. Albany's foggy mornings frost the outdoor coil regularly, so the defrost cycle gets real use, especially on units serving compact bungalows with condensers tucked into small side yards. Once the sensor reading drifts off or the board itself quits, frost keeps building on the coil and heat transfer stops. We compare the sensor reading to actual coil temperature and replace the sensor or board.
Outdoor coil frozen solid. Once a mini-split's defrost function quits working, the outdoor coil can build up a solid layer of ice. Indoors the head puts out air that's noticeably cool, and the outdoor fan can start straining against the ice. We melt the ice and inspect the coil, but the real job is figuring out why the defrost cycle quit rather than just clearing what's built up.
Low refrigerant from a flare leak. Line sets crammed through Albany's small lots and tight ADU walls join with flared fittings, and a slightly loose flare bleeds refrigerant slowly. Heating capacity drops before cooling does. We put the line under pressure to locate the leak, redo or swap the flare fitting, and then charge the system to the correct weight.
Reversing valve won't shift to heat. When the indoor head is running but the air never actually warms up, the reversing valve is often the reason, it may not be moving into the heat position. We take line temperature readings at the outdoor unit to confirm whether the valve is actually switching over, and swap it if it's the cause.
Signal fault between indoor and outdoor units. The indoor head and outdoor unit pass signals back and forth over a control wire, and a break anywhere along it can stop the system cold. A fault code on the head, a corroded terminal, or a failed indoor board can leave an Albany bungalow or UC Village unit idle or stuck. We read the fault history, check the wiring, and isolate the failed board before quoting.
How we diagnose it
- Make sure the head is actually calling for heat and the outdoor unit is answering, then check line temperatures to confirm the reversing valve moved into heat position.
- Look over the outdoor coil for ice buildup and observe a full defrost cycle, comparing the sensor's reading to the coil's actual temperature.
- Pressure-test for refrigerant loss, with attention to the flare connections common on Albany's tight retrofit installs.
- Pull any fault codes stored on the unit and inspect the wiring between indoor and outdoor sections for corrosion or a loose connection.
$99 diagnostic, credited toward the repair. You get a written quote before any work begins.
Heat Pump Not Heating in Albany: common questions
Do you service Albany, or is it too small to bother with?
Why does my mini-split lose heat on foggy mornings?
My mini-split runs but only blows cool air. What's wrong?
Nearby and related
Heat Pump Not Heating near Albany: Berkeley · El Cerrito .
This is usually a heat pump installation & service in Albany job. See our heat pump installation & service overview or the Albany service area.
Heat Pump Not Heating in Albany
Repairs start with a $99 diagnostic, credited toward the fix. Replacing a system? The on-site assessment visit is free. Same-day written findings either way.
Bay Area · 7am–7pm · 7 days · no overtime charges