My furnace turns on and off rapidly. What is wrong?

That is short cycling, and the usual causes are a dirty filter, a failing flame sensor, an oversized furnace, or a thermostat in the wrong spot. One visit is enough to diagnose it, and most of these fixes are inexpensive.

Should I repair or replace an older furnace?

Past 15 years old with a repair quote over half the cost of a new install, replacement usually wins on both cost and efficiency. We price both paths side by side and you choose. No one here earns a commission on replacements.

Do you also service heat pumps?

Yes. Heat pump repair is some of our most common work: reversing valves, defrost controls, refrigerant charge, contactors. We service both ducted systems and ductless mini-splits.

Heating & Furnace Repair in the Bay Area

Heating Repair.

The heat quits at 6am on a cold Bay Area morning, and you want a technician on the way, not a callback ticket. Onzone runs same-day heating repair for furnaces, boilers, and heat pumps.

Combustion safety check on every gas system we touch. Written diagnostic report at the end of every call. No-heat calls jump to the front of the queue every time.

Problems we fix every day.

Furnace won't ignite

A gas furnace that clicks, spins up the inducer, and then gives up is usually stopped by an ignition sensor, a gas valve, or the burners. We find which one and fix that part, not the whole list.

Heat pump blows cold

A heat pump that loses its heat usually has low refrigerant, a reversing valve issue, a defrost fault, or an outdoor fan problem. Each leaves different evidence, and we read it before touching parts.

Boiler heat is uneven

Cold radiators or dead hydronic zones point to circulator pumps, zone valves, trapped air, system pressure, or controls. We bleed, test, and repair until every zone pulls its weight.

Electric furnace trips breaker

An electric furnace that trips the breaker is telling you something is overheating: a sequencer, a heating element, the blower motor, or the wiring. Stop resetting it and call us.

Sage Vikky May 2026

I had an amazing experience with Oleg and Teymur! They repaired my AC and furnace, and also installed a new water heater for me. From the beginning they were friendly, professional, and really knew what they were doing. They took the time to explain everything, answered all my questions, and made me feel comfortable throughout the process. It's hard to find people who truly care about doing quality work, but these guys definitely do. Everything is working perfectly now, and I'm very happy with the results. I highly recommend Oleg and Teymur to anyone looking for honest and reliable service!

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Sally Siao June 2026

I can't say enough good things about the OnZone team. They fixed our basement radiant floor heating which had not been working for over two years. Another company made three separate service visits and still couldn't solve the problem, but OnZone diagnosed and fixed it successfully. Their entire process was outstanding—from scheduling the appointment, to completing the work, to following up afterward. The team was professional, knowledgeable, and easy to work with. I highly recommend OnZone to anyone looking for HVAC or plumbing services. They exceeded my expectations, and I will definitely refer them to my friends.

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Artur D June 2026

Oleg did a great job at our house: he fixed malfunctioning AC unit, adjusted and tuned up a Heater, which is located in the attic. He was punctual and on-time as agreed, and spent time to make sure everything was tested and functioning properly before he left. His prices are very reasonable too. Will call him again if need comes as he is well versed in plumbing and electrical. I am very happy with his services.

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Heating Repair.