Short-Cycling: Menlo Park’s Most Common Furnace Complaint
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A furnace that starts, runs for 2–4 minutes, then shuts off is short-cycling from a tripped high-limit switch. This is the most common furnace service call Appliance ProCare handles in Menlo Park, and the cause is almost always one of three things:

1. A clogged air filter. A dirty filter restricts airflow, the heat exchanger overheats, and the limit switch trips as designed. Check and replace the filter first. If short-cycling resolves after the filter change, you saved yourself a service call.
2. A blocked supply or return vent. Furniture placed over floor registers, or closed vents in unused rooms, restricts airflow the same way a dirty filter does. Check all vents are open and unobstructed.
3. A failing limit switch. If airflow is adequate and short-cycling continues, the limit switch itself has failed or calibrated incorrectly. Replacement: $100–$200.

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If none of these resolve it, call +1 650 535 4433. Persistent short-cycling with clear airflow may indicate a cracked heat exchanger — the most serious furnace failure.

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What the Repair Costs
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• Igniter failure — $100–$220. Most common gas furnace repair. Hot surface igniter cracks and fails to glow.
• Flame sensor failure — $80–$160. Furnace lights then shuts off within seconds. Often just needs cleaning ($60–$100).
• Limit switch failure — $100–$200. Short-cycling with adequate airflow.
• Gas valve failure — $200–$400. No gas flow despite functional igniter and board. California-certified gas work required.
• Draft inducer motor failure — $250–$500. Inducer doesn’t start, preventing furnace operation entirely.
• Control board failure — $200–$500. Erratic behavior, no thermostat response.
• Heat exchanger crack — $600–$1,500+. The most serious failure. Allows combustion gases including CO into living space. Requires complete assessment before any other repair is authorized.

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Heat Exchanger and CO Risk in Menlo Park Homes
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A cracked heat exchanger is the most dangerous furnace failure because it produces no obvious symptom. Combustion gases — including carbon monoxide — leak into the supply air and circulate through the home. CO is colorless and odorless. The first symptoms in occupants are headaches, dizziness, and nausea that resolve when leaving the home.

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Menlo Park’s coastal marine air accelerates heat exchanger corrosion faster than in drier inland climates. Furnaces in homes near the Bay — particularly in Belle Haven, Flood Park, and the areas east of Highway 101 — should receive heat exchanger visual inspections every 3–5 years rather than the standard 7–10 year interval.

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Appliance ProCare technicians use a combustion analyzer on every furnace call — measuring CO concentrations in the flue and supply air as a standard step, not an optional add-on. Findings are documented in writing before any repair decisions are made.

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Repair vs. Replace: Furnace Numbers
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A new 80,000 BTU gas furnace installed: $3,000–$6,000. Most furnace component repairs run $80–$500. The 50% rule applies: repairs under half the replacement cost are almost always the right call. The exception: a heat exchanger crack on a furnace over 20 years old where the repair cost approaches $1,500 and multiple other components are aging. At that point, replacement may be the right decision — and our technician will tell you honestly.

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Brands We Service
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• Carrier & Bryant: Most common furnace brands in Menlo Park. Full repair including Infinity series control boards.
• Trane & American Standard: Complete gas and electric repair support.
• Lennox, Rheem & Goodman: Full parts availability across all model generations.
• Daikin & Amana: High-efficiency gas furnaces with proprietary variable-speed blower systems.

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FAQ
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Q: My CO detector went off near the furnace. Should I call for a furnace repair or a CO emergency?
A: CO detector alarm = immediate action. Evacuate the building, leave doors and windows open as you exit, and call 911. Do not re-enter until emergency responders have cleared the space. After clearance, call +1 650 535 4433 for furnace inspection and heat exchanger assessment.

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Q: My furnace makes a loud bang when it starts. What is that?
A: Delayed ignition. Gas accumulates during the igniter warm-up period, then ignites all at once. The bang is a small explosion inside the combustion chamber. Left unaddressed, it stresses the heat exchanger and eventually cracks it. The fix is usually a cleaning of the igniter and burner assembly ($80–$160) or an igniter replacement ($100–$220). Don’t ignore it.

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Appliance ProCare holds California Business License #A 50621 and carries $1,000,000 General Liability Insurance. All gas furnace work by California-certified technicians with CO detection equipment. For furnace repair in Menlo Park, call +1 650 535 4433.