A & B Mechanical Inc
C-4| C20| C38HAYWARD, CA 94544
(510) 264 5800View profileLicensed under Class C-4 (Boiler, Hot Water Heating and Steam Fitting)
Find CSLB-licensed boiler and heating contractors in California. Every listing shows an active licence number you can check yourself.
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Boiler and hydronic heating work in California involves pressurized vessels, combustion air and relief valves — failures are serious. Converting from steam to hot water is an engineering decision, not a equipment swap.
Radiant floor systems need proper tubing layout and slab insulation. Ask whether the contractor balances zones after startup and provides operating instructions.
Hydronic systems with old radiators may need trap and vent assessment when converting from steam. Mixing steam hardware with hot-water flow causes noise and poor heat.
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Get matched with a licensed proClass C-4 (Boiler, Hot Water Heating and Steam Fitting) covers boiler, hot water heating and steam fitting — CSLB authorizes work on heating plants and related piping. It is separate from HVAC air-side work. Radiator valve replacement during boiler upgrades is often wise on century-old systems even when radiators look fine from the outside.
Contractors hold an active Class C-4 (Boiler, Hot Water Heating and Steam Fitting) licence at a California address. Boiler replacements usually need mechanical permits through the building department with jurisdiction over your address. Expansion tank sizing must match system volume, and an undersized tank causes relief valve dripping that looks like a leak. Bleed air from radiators with the technician present because owners who skip this step call back noisy.
The register does not show combustion analysis results. Ask whether tuning and CO testing are part of startup. Hydronic zone valves that fail closed can block heat to a wing of the house, and labeling zones at the manifold saves service time.
Combustion air louvers are code-sized to the appliance input rating. Closing off a louvered door after install can starve the burner of air. Payment should track inspection milestones in California, not calendar dates alone, so you can verify boiler heating progress before each draw. Payment should track inspection milestones in California, not calendar dates alone, so you can verify boiler heating progress before each draw. Payment should track inspection milestones in California, not calendar dates alone, so you can verify boiler heating progress before each draw.
Every licence number below links to its record at cslb.ca.gov, where you can confirm status and expiry yourself.
635 active CLEAR licences statewide · page 1 of 27
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Get matched with a licensed proBoiler and hydronic heating work requires Class C-4 (Boiler, Hot Water Heating and Steam Fitting). Gas connection may coordinate with the utility and inspector.
The register shows 0 with an active Class C-4 (Boiler, Hot Water Heating and Steam Fitting) licence at a California address.
Most boiler installations need mechanical permits and inspection through the building department with jurisdiction over your address. Operating without a permit can affect insurance.
Heat exchanger condition, parts availability and efficiency drive the math. A contractor should document why repair is viable before quoting it.
Water quality, relief valve testing and combustion checks are periodic tasks. Ask for a maintenance sheet at startup.