Endless Hot Water Starts With a System That Performs Right

Tankless water heaters deliver efficiency and convenience — but they rely on precision components that need proper care to stay reliable. Whether yours needs cleaning, performance testing, or repairs, our technicians provide clear guidance and clean, dependable service.

Why Tankless Systems Need Specialized Care

Tankless water heaters operate differently from traditional tanks. Instead of storing hot water, they heat it on demand — which means every sensor, burner, fan, and flow control has to work perfectly in real time.

Professional tankless service helps:

  • Maintain steady water temperature

  • Improve response time

  • Reduce energy usage

  • Prevent scale buildup

  • Extend the lifespan of the system

  • Minimize noise, errors, and shutdowns

A well-maintained tankless unit keeps your home supplied with reliable, efficient hot water year after year.

Signs Your Tankless System Needs Attention

Tankless units tend to show performance changes before they fail completely. These changes are often subtle but noticeable if you know what to look for.

Service is usually needed when you notice:

  • Inconsistent or fluctuating water temperature

  • “Cold sandwich” bursts between hot water cycles

  • Longer wait times before hot water reaches the tap

  • Strange noises from the unit

  • Reduced water flow

  • Error codes or warning lights

Any of these can signal scale buildup, sensor issues, ignition trouble, or ventilation problems — and our technicians can identify what’s going on quickly.

What to Expect During Tankless Service

Tankless systems run best when each component is clean, calibrated, and functioning as designed. Our service process gives you clarity at every step.

Here’s how we handle your visit:

  1. Conversation & System Review
    We start by understanding what you’re experiencing — temperature swings, slow heat-up time, or error codes.

  2. Performance Assessment
    We evaluate temperature stability, flow rate, gas/air mixture, ignition, and burner performance.

  3. Deep Cleaning & Descaling
    Hard water scale is the biggest enemy of tankless systems. We flush and descale the unit to restore efficiency.

  4. Sensor & Control Testing
    Flow sensors, thermostats, fan motors, and safety systems are tested for proper communication and operation.

  5. Clear Results & Recommendations
    You get a plain-language breakdown of how the system is performing and what we recommend moving forward.

Every visit ends with a cleaner, more responsive, more efficient system.

Common Tankless Problems We Solve

ankless units are reliable but require precision repairs when something fails. Our technicians diagnose issues accurately and complete repairs with attention to safety and long-term performance.

We repair:

  • Ignition and burner problems

  • Flow sensor failures

  • Venting and airflow issues

  • Scale buildup causing reduced output

  • Temperature fluctuation or “cold bursts”

  • Error codes related to combustion or flow

  • Fuel or electrical component failures

If a repair is the right move, we’ll tell you. If replacement is smarter, we’ll explain why — without pressure.

Annual Maintenance Protects Your Investment

Tankless water heaters operate continuously with high internal temperatures, which means maintenance isn’t optional — it’s essential. Even small amounts of mineral buildup can affect output, efficiency, and lifespan.

Maintenance typically includes:

  • Full system flush and descaling

  • Filter cleaning

  • Burner and flame inspection

  • Testing sensors, fans, and ignition

  • Checking venting and air supply

  • Verifying temperature accuracy and flow rate

One visit can dramatically improve performance and reduce the risk of shutdowns or expensive repairs.

Why Homeowners Choose Dave’s

Experience You Can Feel

We’ve served Northern Virginia homes for 50 years.

Fair, Upfront Pricing

No upsells, no hidden fees — just straight answers.

Local & Reliable

 Based right here in Sterling, ready when you need us.

Respectful Service

We treat every home like it’s our own.

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Dependable Hot Water to Keep Your Home Comfortable

Dedicated to Your Comfort Since 1975

At Dave’s Heating & Air, we know how important reliable hot water is to your home. Whether we’re repairing your current system or installing a new one, our team takes the same careful, honest approach we’re known for.

We explain what we find, walk you through your options, and outline the cost before any work begins — no surprises and no pressure.

Our technicians take the time to do the job the right way, from clean, precise installations to thorough safety checks on every visit. And because we stand behind our workmanship, your water heater service comes with a written guarantee.

When you choose Dave’s, you get dependable hot water and a team that treats your home with respect every step of the way.

Call 571.346.3940 and let’s keep your home comfortable!

Hear It from Our Happy Customers

Nothing makes us prouder than hearing directly from the wonderful people we serve right here in Sterling, Herndon, Reston and Northern Virginia. Our reputation is built on knowledgeable technicians, courteous service, and the promise that we always leave your home as clean as we found it—if not cleaner!

Customers regularly praise our team for arriving on time, delivering expert system installations and repairs, and ensuring the whole process is seamless from start to finish. Whether it’s a complete HVAC replacement or routine maintenance, folks appreciate the extra care and attention to detail we bring. Many even say they’d recommend us to friends and neighbors without hesitation. Now that’s high praise!