Seasonal tune-up and full diagnostic on your Carrier, Trane, or Goodman system - readings shown to you before any repair is proposed
Diagnosis first, numbers second - you approve the repair price before a single part goes in.
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AfterFast, Reliable Furnace Repair Across San Lorenzo
Most furnace repairs in San Lorenzo run $150 – $700 and are completed in a single visit. Our technicians carry the common parts for Goodman, Rheem, York, and Daikin units on every truck, and we dispatch from our San Francisco Bay Area office to reach San Lorenzo homes quickly.
We’re familiar with the specific heating systems in San Lorenzo because we’ve worked on so many of them. The Bohannon-era tract homes that define this community, built slab-on-grade from 1947 to 1955, came with gravity floor furnaces cast directly into the concrete. That construction method creates repair and replacement challenges you won’t find in Castro Valley or San Leandro, where crawl spaces allow conventional ductwork routing. When your heat goes out on a cold night near Hesperian Boulevard or along Via Mariposa, you need a technician who understands why the fix isn’t always straightforward. Call us at (984) 538-9003. A live person answers, 24 hours a day.
Why Brandt HVAC Is San Lorenzo’s Preferred Furnace Repair Company
We’ve built our reputation in San Lorenzo by showing up with our names and photos already sent to your phone, and a photo ID badge at your door. That’s the Threshold Verified standard. Every Brandt HVAC technician is background-checked and identity-verified. If someone arrives who you weren’t told to expect, that visit is on us.
Our San Lorenzo customers tell us the same thing repeatedly: they chose us because they knew exactly who was walking through their door. Parents with young children, older homeowners living alone, shift workers home during odd hours. They don’t want a stranger. They want Devin Marlowe’s team, introduced by name before arrival.
Response time to San Lorenzo is coordinated from our Bay Area dispatch office. We know the local streets, the Bohannon tract layout, and the specific permit requirements Alameda County enforces for any furnace work in these slab homes. That local knowledge saves hours on every job.
Every repair begins with a written price before any work starts. No exceptions. Every repair also carries a written guarantee: our 365-Day Done Right Promise. If the fix fails, we return at no charge. No argument. No additional fee.
Boiler Repair in San Lorenzo
Boiler Repair in San Lorenzo is less common than furnace work, but the homes that have them, typically mid-century models in the Bohannon tracts that were spec’d with hydronic heat instead of gravity floor furnaces, need specialized attention. A typical boiler repair in San Lorenzo runs $150 – $700, same as our furnace range, though parts for older cast-iron models can push toward the higher end if the aquastat, circulator pump, or expansion tank has failed. We service all major residential brands and carry common replacement components for Rheem and York boiler systems on our trucks.
Signs Your Boiler Needs Attention
Listen for kettling, that rumbling sound like a teapot, which means sediment has hardened in the heat exchanger. Watch for pressure drops on the gauge, or radiators that heat unevenly. In San Lorenzo’s older homes, corrosion from decades of mineral buildup often attacks the circulator pump first.
What Boiler Repair Involves
We’ll drain the system, inspect the heat exchanger for cracks or scaling, test the circulator and zone valves, and check the expansion tank’s air charge. If the boiler is beyond repair, we’ll give you a written replacement price with no pressure. The decision is yours, and we’ll explain every option in plain language.
Gas Furnace Repair in San Lorenzo
Gas Furnace Repair in San Lorenzo is the core of what we do, and it’s rarely a simple parts swap in this community. The original gravity floor furnaces cast into Bohannon slabs develop cracked heat exchangers and corroded flue connections that cannot be replaced in place under current Alameda County mechanical code. When we open a slab pocket on Via Mariposa or near Lewelling Boulevard, we often find the repair has become a full heat-delivery redesign. Most gas furnace repairs in San Lorenzo fall between $150 – $700, but jobs requiring attic air handlers and high-wall registers run higher due to the added labor and materials.
Common Gas Furnace Failures
Ignitor failure is the quickest fix. A hot-surface ignitor that won’t glow means no flame, no heat. We stock replacements for Goodman and Daikin units. Gas valve problems are more serious. If the valve won’t open or won’t prove flame through the thermocouple, the system locks out for safety. We’ll test microamps and replace only what’s failed.
When Repair Becomes Replacement
In San Lorenzo’s slab homes, this threshold arrives faster than elsewhere. A cracked heat exchanger in a floor furnace means the unit cannot be replaced in the same slab pocket. The code requires a redesigned system, typically an attic air handler with high-wall registers. We’ll show you the written price for both paths and let you decide.
Trusted Brands We Service in San Lorenzo
We service all major residential HVAC brands: Carrier, Trane, Lennox, Goodman, Rheem, York, Daikin, Bryant, and American Standard. For San Lorenzo customers, we stock the most common failure parts locally, ignitors, gas valves, blower motors, and control boards for Goodman and Rheem systems, which we see frequently in East Bay retrofits. That local parts inventory means faster turnaround. You’re not waiting a week for a control board to ship from a regional warehouse. Our technicians also carry York and Daikin components for the newer high-efficiency furnaces that have replaced original slab units in many San Lorenzo homes over the past decade.
Common Furnace Repair Problems We See in San Lorenzo Homes
- Cracked heat exchangers in original floor furnaces. The cast-in slab units from the Bohannon era develop metal fatigue after 70+ years of thermal cycling. Once cracked, they leak combustion gases into the living space, and Alameda County code prohibits a simple drop-in replacement, forcing a full system redesign.
- Accelerated rust from marine air exposure. San Lorenzo’s proximity to San Francisco Bay means salt-laden fog corrodes furnace cabinets, burners, and flue assemblies years faster than identical equipment in Livermore or Pleasanton. The original floor furnaces sit in damp slab pockets with poor ventilation, worsening the damage.
- Failed ignitors on retrofitted attic systems. Many San Lorenzo homes have already moved to attic air handlers, but the added static pressure of high-wall register routing strains blower motors and causes frequent cycling, which wears out hot-surface ignitors faster than in conventional ducted systems.
- Corroded flue connections in slab pockets. The vent path from a floor furnace runs through concrete and often terminates near grade level, where moisture and salt air attack the metal. We’ve replaced flue assemblies where the pipe has rusted through completely, creating a carbon monoxide hazard.
Pricing for Furnace Repair in San Lorenzo, CA
We’re transparent about what furnace repair costs in San Lorenzo because these homes present conditions that genuinely affect price. Most repairs fall between $150 – $700, with the majority of ignitor replacements, control board swaps, and blower motor repairs landing in the $200 – $450 range. The higher end typically involves jobs where the original slab furnace must be abandoned and a new attic system designed.
| Service | Price Range in San Lorenzo |
|---|---|
| Furnace Repair | $150 – $700 |
| Furnace Tune-Up | $80 – $200 |
What moves a job toward $700? Heat exchanger replacement in a slab-on-grade home, where code requires relocating the system. Multiple failed components discovered during diagnosis. Emergency after-hours calls, though we never charge overtime, just our standard rate. Every repair begins with a written, itemized price. You see the cost. You approve it. Then we start. Estimates are free. Call (984) 538-9003.
We Also Serve Cities Near San Lorenzo
Our crews work throughout the East Bay, including Furnace Repair in San Lorenzo and neighboring Castro Valley, San Leandro, Union City, and Oakland. Dispatch and scheduling are coordinated from our San Francisco Bay Area office. Whether you’re in the flatlands near the Bay or up in the Oakland hills, the same Threshold Verified standard applies: background-checked technicians, sent to you by name and photo, with written upfront pricing on every job.
Serving San Lorenzo, CA - Our Local Coverage Area
We’re based in the San Lorenzo area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
FAQs About Furnace Repair in San Lorenzo
We can repair many original floor furnaces if the heat exchanger is intact and the flue is sound. However, if the heat exchanger is cracked or the flue is corroded, Alameda County mechanical code prohibits replacing the unit in the same slab pocket. That forces a full heat-delivery redesign, typically an attic air handler with high-wall registers. We’ll inspect yours and give you a written price for both paths. Call (984) 538-9003 for a free estimate.
Marine air off San Francisco Bay carries salt that accelerates corrosion on furnace cabinets, burners, and flue assemblies. In San Lorenzo’s slab-on-grade homes, the original floor furnaces sit in concrete pockets with poor ventilation, trapping moisture against the metal. Livermore sits inland, beyond the marine layer, with drier air and slower corrosion rates. We recommend corrosion-resistant replacement equipment and more frequent maintenance intervals for coastal East Bay homes.
A rumbling noise usually means delayed ignition, often from dirty burners or a failing gas valve. That’s typically repairable in the $150 – $400 range. But in a Bohannon slab home, we always inspect the heat exchanger while we’re there, because if it’s cracked, the code requires replacement with a redesigned system. We’ll know once we open it up and look. Estimates are free.
Not directly for heating, but the Diablo wind events that push San Lorenzo into the 90s and 100s create sudden first-time cooling demand in homes that never had air conditioning. Many homeowners use that heat spike as the trigger to replace an aging floor furnace with a system that handles both heating and cooling, typically a ductless mini-split or an attic heat pump. We can size and price both options.
Most repairs run $150 – $700, but San Lorenzo’s slab-on-grade construction often turns a simple repair into a system relocation. When Alameda County code prevents dropping a new unit into the original slab pocket, the job requires attic air handlers, high-wall registers, and static-pressure engineering that doesn’t arise in crawl-space homes in San Leandro or Castro Valley. We explain exactly why your specific job costs what it does, with a written price before any work starts. Call (984) 538-9003 for your free estimate.
Brandt comes from an old word for a firebrand, a fitting name for the work of keeping a home warm. Our Furnace Repair team brings that same straightforward heat to every San Lorenzo job, whether it’s a quick ignitor swap on a retrofitted attic system or a full heat-delivery redesign from a 70-year-old slab furnace. We’re part of the Threshold Group family, established in 2003, and every Brandt HVAC location is independently owned and operated. Devin Marlowe leads ours.
When you’re ready, call (984) 538-9003. A live person answers, 24 hours a day, 7 days a week. No voicemail. No callback queue. We’ll send you your technician’s name and photo before arrival, show a photo ID badge at your door, and put the price in writing before any work begins. That’s the Threshold Verified standard, and it’s how we work in San Lorenzo.
Written by Devin Marlowe, Owner at Brandt HVAC, serving San Lorenzo and the East Bay.