Heat Pump Not Cooling in Danville

Heat Pump Not Cooling in Danville

A heat pump cools exactly the way an AC does, by pulling heat out of the house and rejecting it outside. The one extra part is a reversing valve that flips the refrigerant flow so the same equipment heats in winter. When a Danville heat pump runs but won't cool, we diagnose it as an AC no-cool, then check the valve. It's almost always one component, not a system at end of life.

Danville's heat makes the problem urgent. Inland summers here run 90-plus from June into September, and a heat pump short on capacity gets caught the first hot week. The housing split matters too. Many of the older ranches off Diablo Road run simpler single-zone systems, while a lot of the Blackhawk and Tassajara estates run multi-zone equipment where a control or zone-damper fault can leave one part of the house warm while the rest cools fine.

Most of what stops cooling is a worn part, a refrigerant leak, a dirty coil, or on the bigger homes a control board that's drifted. All of it is diagnosable and most of it is fixable on the first visit. We read the system, find the specific fault, and put the repair on a written estimate before any work starts.

Common causes

Reversing valve stuck in heat mode. The valve that switches a heat pump between heating and cooling can stick or lose its solenoid, leaving warm air on a cooling call. We read line temperatures and test the solenoid coil to confirm it, then replace the valve or coil depending on what failed.

Control board fault on multi-zone systems. A fair number of Blackhawk and East Danville homes run zoned variable-speed equipment, and those boards drift over time. A board or zone-damper fault can stop cooling to one zone while the others work. We pull codes, test the dampers, and repair or replace the board with the correct part.

Low refrigerant from a leak. Low charge cuts cooling capacity and can freeze the indoor coil. Refrigerant isn't consumed, so low means a leak. We locate it with electronic detection or pressure testing, repair it, and weigh in the proper charge rather than topping off.

Failed capacitor. A degraded capacitor keeps the compressor or outdoor fan from starting, and the unit runs without cooling. It's the most common single-zone Danville summer failure. We meter it and carry the replacement on the truck.

Dirty outdoor coil. Danville summers leave dust and pollen on the outdoor coil, and a clogged coil can't reject heat. The compressor works harder, head pressure rises, and cooling falls off. We clean it and confirm the pressures recover.

Frozen indoor coil from low airflow. Older homes off Diablo Road often have tight crawl spaces, which makes condensate and airflow restrictions more common. A clogged filter or weak blower ices the coil and blocks airflow. We thaw it, clear the restriction, and verify it stays clear.

How we diagnose it

• On multi-zone Blackhawk systems, confirm whether the no-cool is system-wide or one zone, which points us at the control board or a damper rather than refrigerant.
• Confirm the reversing valve is actually switching to cooling and isn't stuck in heat.
• Test the capacitor and contactor with a meter before touching refrigerant.
• Read refrigerant pressures against the target and leak-test if the charge is low.
• Inspect the outdoor coil, indoor filter, and condensate path, the last one a recurring issue in the older Diablo Road crawl spaces.

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

Heat Pump Not Cooling in Danville: common questions

Nearby and related

Heat Pump Not Cooling near Danville: San Ramon · Alamo · Blackhawk · Walnut Creek · Pleasanton .

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