Tiburon, Belvedere and Mill Valley have mild summers and long, cool, damp stretches the rest of the year, so the heat runs many more hours than the air conditioning. Homes here are heated in very different ways: a gas furnace with ducts, a boiler feeding radiant floors or baseboards, a heat pump, ductless units, or a mix of these in a larger house with several zones. Any heating repair starts by identifying the system and the part of it that has stopped working.
Which system do you have?
| System | Typical complaint | Common causes |
|---|---|---|
| Gas furnace | Blower runs but air is cold; no heat at all | Igniter, flame sensor, pressure switch, blocked vent or drain, control board |
| Boiler with radiant floors or baseboards | One zone cold; boiler short-cycling; pressure dropping | Zone valve, circulator pump, air in the loops, expansion tank |
| Heat pump | Lukewarm air; ice on the outdoor unit; runs nonstop | Defrost fault, reversing valve, refrigerant leak, backup heat failure |
| Ductless mini-split | Blinking code; one head not heating | Sensor, board, communication wiring, dirty blower wheel |
| Electric furnace or wall heater | Some heat but not enough; breaker trips | Heating element, sequencer, limit switch, wiring |
Gas furnaces are covered in detail on furnace repair, heat pumps on heat pump repair, and wall-mounted ductless units on mini-split repair.
Radiant and hydronic heat
Radiant floors and baseboard systems heat with hot water from a boiler, pumped through loops and opened to each zone by valves. They are quiet and even, and their failures look nothing like forced-air problems. A zone that stays cold usually points to a stuck zone valve, a failed circulator or air in the loop. A boiler that keeps losing pressure suggests a leak or a waterlogged expansion tank, while a dripping relief valve suggests pressure that is too high. Mixing valves, which blend the water down to a temperature that is safe for floors, can stick as well. We test the boiler’s ignition and safety controls together with the piping, because a “boiler problem” often turns out to be in the distribution. For boiler and tankless equipment, see our Navien and Noritz pages.
How a heating repair visit works
- Call. Tell us what the system is doing and how long it has been happening. A noise, a smell or an error code all help.
- Scheduling. Same-day visits are usually available, and no-heat calls are answered 24/7.
- Diagnosis. The technician tests in sequence: thermostat and power, ignition or compressor, safety controls, then distribution through ducts or pipes.
- Quote. You see the repair price before any work starts.
- Repair and check. The system runs through a full heating cycle afterward, and the repair carries a 90-day warranty.
Safe checks before you call
- The thermostat is on Heat, set above room temperature, with working batteries.
- The service switch near the furnace or air handler (often a light switch) is on, and the front panel is closed.
- The filter is clean.
- For a boiler, note the pressure gauge reading; for a heat pump, make sure the outdoor unit is not buried in leaves.
If you smell gas or a carbon monoxide alarm sounds, leave the house and call 911 or your gas utility from outside first.
Older systems
Many Mill Valley homes date from the early 1900s to the 1960s, and older cottages on the Tiburon peninsula can have heating equipment that has been in place for decades. We repair older systems when parts are available and the equipment is safe, and we say so plainly when it is not. The local pages cover heating repair in Tiburon, Belvedere and Mill Valley. For a no-heat night, see emergency HVAC service.