Bosch heating and cooling for homes comes in three forms we service: inverter heat pumps that feed a ducted system, ductless units that heat and cool single rooms, and geothermal heat pumps that draw on a ground loop. All three move heat rather than burn fuel, and all three behave differently from the older furnace-and-AC pairs found in many homes in Novato, San Rafael and Larkspur. Bosch, founded in Stuttgart, Germany, in 1886, builds this equipment around variable-speed compressors, so a fair diagnosis starts with knowing what normal operation looks like.
Inverter heat pumps: normal and not normal
An inverter heat pump changes compressor speed to match the load. On a mild day it may run for hours at low speed, using little power and making little noise; on a cold morning it ramps up. A Bosch unit that “never shuts off” may be doing exactly what it was designed to do. These are the signs that something is wrong:
- the house misses the setting by more than a degree or two for hours;
- the outdoor unit runs at full speed all the time, even on mild days;
- the outdoor coil stays iced after a defrost cycle;
- the indoor air feels cool in heating mode for more than a few minutes;
- the system starts and stops every few minutes, which inverter equipment should rarely do (see short cycling).
Those symptoms point to airflow, refrigerant charge, a temperature sensor or the inverter board. Inverter equipment also reports its own faults, so we read the code first and then confirm it with measurements, because a code names a circuit, not always the failed part.
Ductless Bosch systems
A ductless system puts a wall, ceiling or floor unit in the room and links it to an outdoor unit through a refrigerant line set, a drain line and a control cable. Service covers the washable filters, the indoor coil and blower wheel (which collect dust and, in damp rooms, mold), the condensate drain and any pump fitted to it, and the flare joints where refrigerant leaks most often start. Our ductless mini-split page covers single-room and multi-room repairs.
Geothermal: the loop matters as much as the unit
A geothermal, or ground-source, heat pump exchanges heat with water circulating through pipes in the ground or drawn from a well. Indoors it looks like a compact furnace cabinet. Many problems start on the water side: a failed loop pump, air trapped in a closed loop, low loop pressure, the antifreeze mix on a closed loop, or a strainer and heat exchanger fouled by mineral scale on an open-loop system. We measure loop pressure and the temperature change of the water across the unit, alongside the usual refrigerant and electrical checks.
Common problems on Bosch equipment
Temperatures that swing and airflow that varies from room to room usually trace back to a dirty filter or a thermostat problem, so both are checked first. On a heat pump the thermostat must be set up for heat pump operation and for any backup heat; set up as a plain AC, it can leave the reversing valve or the backup idle. Clogged condensate drains are the other frequent call. A blocked drain on an air handler or a ductless head can overflow onto a ceiling or wall, so a drip or stain near an indoor unit deserves a prompt look. If weak airflow is the main complaint, our poor airflow page lists what to check.
How we handle the repair
Some Bosch parts are model-specific and have to be ordered, so we confirm availability and timing before you approve the work. You get an itemized price after the diagnosis. The parts we install are factory certified and carry the manufacturer’s warranty, and our work carries a labor warranty. We are independent and not affiliated with Bosch, so the job is to repair the system you have.
Local notes
Many older Marin homes were built without central air, and a heat pump is a common way to add cooling while replacing an aging heating system. In Sausalito, salt air near the water corrodes outdoor coils and fins faster, so inspection and a fresh-water rinse of the coil matter more there. Heat pumps run for much of the year in this climate, which makes a yearly maintenance visit worth more than it would be somewhere with a short heating season.