No heat or no cooling
Checking the thermostat call, outdoor unit, reversing valve and controls to find why the system runs but does not heat or cool.
Mill Valley heat pump short cycling, frosting over or throwing a code? HAXX repairs ducted and ductless heat pumps from the canyons to the flats.
Serving Sycamore Park, Blithedale Canyon, Cascade Canyon, Scott Valley, Middle Ridge and nearby Homestead Valley and the rest of Mill Valley. Share your address to confirm availability.

Ducted systems, ductless mini-splits and multi-zone heat pumps. Tell us what the system is doing and we start the visit with that symptom.
Checking the thermostat call, outdoor unit, reversing valve and controls to find why the system runs but does not heat or cool.
Some frost in winter is normal. A unit that stays iced points to airflow, refrigerant or defrost-control problems.
Blinking lights and error codes on Mitsubishi, Daikin, Fujitsu and other ductless systems, traced to the sensor, board or refrigerant issue behind them.
Units that start and stop, rattle, hum or trip the breaker are checked for electrical, airflow and sizing problems.
Clogged condensate lines and drain pumps cleared and tested before water damages the wall.
If the system is not worth fixing, you get the reasons in writing and options to compare, not pressure.
Mill Valley heat pumps work in damp, shaded canyons under redwoods as well as on sunny lots in Sycamore Park. Moisture, debris and tight equipment spaces shape most repair calls here.
Outdoor units in Blithedale and Cascade Canyon collect needles, leaves and moisture. HAXX clears coils, checks defrost controls and tests fan motors.
Mini-split heads added to older cottages and cabins often fail on drain lines, sensors or communication wiring. Each is tested before parts are ordered.
As a licensed electrician too, HAXX checks breakers, disconnects and low-voltage wiring during the same visit.
Rated 4.8 across 515+ reviews on Housecall Pro, Google and Facebook. Read more reviews.
“Their technician was professional, honest, and took the time to explain the problem and the repair process clearly. Instead of pushing for an expensive replacement, they repaired our HVAC system and helped us save a significant amount of money. The work was completed carefully, and our air conditioner is now working well.”
“Thorough diagnostics of A/C system, identified and repaired the issue quickly!”
“Service was performed well and on time. Service person was highly skilled and provided easy to understand options to deal with the issue. Price for diagnostics was reasonable and easy to pay online.”
Brand, model and what it is doing. Photos of the label or error code help.
The technician tests the system and finds the cause, not just the symptom.
You see the repair price before work starts, and the options if a repair is not worth it.
The repair is completed and tested, or scheduled once the part arrives.
A closer look at recent heating and cooling work by HAXX.

On site during a commercial VAV box repair: access above a suspended ceiling, equipment and the work in progress.
Explore recent projects
Heat pump air handler service.

Compressor replacement.

Mitsubishi leak detection.

After-hours system repair.

Heat pump installation.

Outdoor heat pump installation.

Heat pump air handler installation.

Lennox ac installation.
Some frost is normal and should clear in defrost mode. Heavy ice usually points to a defrost sensor, control board, low charge or blocked airflow. HAXX tests each.
Yes. HAXX services heat pumps throughout the Mill Valley area, including unincorporated neighborhoods.
It depends on the fault, the refrigerant the system uses and the condition of the compressor and coils. HAXX explains the repair cost against replacement options so you can decide.
Yes. HAXX services wall, ceiling cassette and ducted mini-split heads, single-zone and multi-zone.
Share the property, equipment and questions you have in mind.
(408) 901-8315
Call HAXX to discuss your property and scheduling.
