Tankless Water Heater
Condensing tankless water heaters for reliable hot water, proper sizing, and efficient installation.
ABC Service evaluates fixture demand, gas line capacity, venting requirements, and recirculation options so hot water arrives quickly and the system performs correctly.
Services We Provide
Tankless Installation
We install condensing tankless units from Navien, Rinnai, and Noritz — interior or exterior, gas or propane.
Tank-to-Tankless
We handle full conversions including gas upsizing, venting, condensate, and recirculation.
Tankless Repair
Our team handles error-code diagnosis, flame-rod and fan replacement, and control-board service.
Descaling & Service
We perform annual flush, inlet filter service, and burner inspection to protect the heat exchanger.
Ready to schedule tankless water heater?
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Authorized Navien Tankless Service
Diagnostics, descaling, maintenance, warranty support, and recirculation troubleshooting on NPE-A2, NPE-S2, and legacy Navien tankless platforms.
Not just new equipment — a system done correctly.
Tankless Installation
ABC Service sizes tankless units to actual fixture demand and incoming groundwater temperature — not the marketing GPM rating on the box. Gas line capacity is verified with a manometer under load, venting is run to manufacturer spec, and combustion is measured with an analyzer at commissioning.
An honest sizing conversation up front is what prevents the lukewarm-shower complaints that drive most tankless dissatisfaction. We install condensing units from Navien, Rinnai, and Noritz with dedicated stainless or PVC venting, proper condensate routing, and gas work upsized where the calculation demands it.
Tank-to-Tankless
Most tank-to-tankless conversions require more than swapping the appliance. We upsize the gas line where the calculation demands it, reroute or add stainless or PVC venting to manufacturer spec, run condensate drainage, and add a recirculation strategy so the homeowner doesn't trade a slow recovery for a long hot-water wait.
We pull the permit, coordinate gas-meter capacity with PG&E when relevant, and remove the old tank and flue cleanly. The result is a wall-mounted system that reclaims floor space, delivers endless hot water, and is commissioned with the same combustion and recirculation discipline as a new-construction install.
Tankless Repair
Our team diagnoses error codes, flame-rod and ignition faults, fan and inducer failures, flow-sensor issues, and control-board problems on the dominant Bay Area brands. We stock common consumable parts so most repairs are completed on the first visit instead of waiting on shipping.
Many 'slow hot water' or 'cold-water sandwich' complaints turn out to be missing or misconfigured recirculation rather than a failed unit. We diagnose the whole hot-water delivery system — dedicated, crossover, or on-demand recirculation — and program the schedule against actual household usage.
Descaling & Service
Annual descaling with a calibrated pump and proper chemistry preserves heat-exchanger capacity, protects the manufacturer's warranty, and is the single biggest factor in pushing a condensing tankless past the 15-year mark in Bay Area water conditions.
Our service visit includes isolation-valve flush, inlet filter cleaning, burner and flame-rod inspection, combustion verification, and a written report on operating performance. We track service history so the next visit picks up where the last one left off, not from scratch.
Thinking about tankless water heater?
Get a fixed-price proposal from a licensed specialist. Same-day response.
Why this is worth doing right.
Endless hot water
Sized correctly, a tankless never runs out — even with simultaneous showers and a tub fill.
Lower operating cost
Condensing tankless models hit 0.93–0.96 UEF, with no standby losses from a hot tank sitting idle.
Smaller footprint
Wall-mounted units recover floor space in garages and mechanical rooms.
Done-right matters
Most tankless complaints come from undersized gas, bad venting, or no recirculation — all preventable.
Manufacturers We Service
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How a tankless water heater project runs.
- 01Evaluate
We assess existing equipment, loads, venting, electrical, and site constraints on-site.
- 02Design
We size and specify equipment to the building — with options and trade-offs explained plainly.
- 03Install
A dedicated lead tech handles a permitted, clean install with finish-grade workmanship.
- 04Commission
We start up, balance, and verify the system against design intent with calibrated instruments.
- 05Support
We walk you through operation, file rebates, and stand behind the system long-term.
Tankless Water Heater: frequently asked
Trusted Across the Bay Area
Homeowners and businesses across the Bay Area trust ABC Service for hydronic heating, HVAC, boilers, heat pumps, and electrical work.
Extremely clean boiler installation and excellent communication throughout. They engineered the system properly instead of just swapping a unit on the wall.
Fast response and genuinely knowledgeable about radiant heating. Heat pump retrofit and panel upgrade done in one project — permits and rebates included.
Professional team, clean work, and honest diagnostics. Upsized our service for the EV charger — on time, on budget, and inspected the same week.
Tankless install with recirculation done right. Coordinated cleanly with our GC and walked us through every decision. Easily the most professional trade we worked with.
Radiant floors throughout a remodel. They designed the manifold layout properly and the comfort is incredible. Quietest system we've ever had.
Furnace replacement plus new ductwork. Quiet, efficient, and the crew treated our house better than we would have. Inspection passed first try.
Honest diagnostics and skilled HVAC technicians. They took the time to walk through the system and explain every recommendation.
Engineered for the Bay Area
From the Peninsula to the South Bay, San Francisco, and the Santa Cruz coast — we design, install, and service premium mechanical and electrical systems across six counties. Our team supports high-efficiency boilers, hydronic heating, HVAC, heat pumps, and electrical upgrades for modern Bay Area homes and light commercial properties.
- Santa Clara County
- San Mateo County
- San Francisco County
- Santa Cruz County
- Contra Costa County
- Alameda County
* Additional service areas available upon request.
