Tankless Water Heater Repair in Arlington Heights, IL

Last updated April 16, 2026 Reviewed by our licensed Chicago master plumber team

When Arlington Heights homeowners and businesses need professional tankless water heater repair services, they turn to Plumbers 911 Chicago. We've been serving the Arlington Heights community and surrounding Cook County neighborhoods with expert plumbing solutions backed by licensed, bonded, and insured technicians.

Tankless water heaters are built to last 15–20 years, but they're not maintenance-free. When your tankless unit stops producing hot water, delivers inconsistent temperatures, or displays an error code, you need a plumber experienced with tankless-specific diagnostics. Plumbers 911 repairs all major tankless water heater brands in Arlington Heights — including Rinnai, Navien, Noritz, Rheem, and Bosch — and we understand the unique issues these units face in our area.

Common Tankless Water Heater Problems

No Hot Water — Ignition failure, gas supply issues, flow sensor malfunction, or a tripped safety switch. We diagnose whether the problem is fuel supply, electrical, or mechanical.

Fluctuating Water Temperature (Cold Water Sandwich) — A common complaint with tankless units, especially during short, repeated draws. This can indicate a flow sensor issue, scale buildup on the heat exchanger, or an undersized unit for the demand.

Error Codes — Tankless units display diagnostic error codes that pinpoint the issue. Common codes relate to ignition failure, flame loss, exhaust blockage, scale buildup, and sensor malfunctions. We're familiar with error codes for all major brands.

Scale Buildup — Arlington Heights water has moderate hardness (7–8 grains per gallon). Without regular descaling, mineral deposits accumulate on the heat exchanger, reducing efficiency and eventually causing overheating shutdowns. Annual flushing prevents this.

Exhaust/Venting Issues — Blocked or improperly sized venting can cause the unit to shut down for safety. Common after bird nests, ice blockage in winter, or if the original installation used undersized vent pipe.

Flow Rate Problems — Unit activates and deactivates erratically due to low flow (below the minimum activation threshold), a failing flow sensor, or partially closed valves.

Tankless Water Heater Maintenance

Annual Descaling (Flushing) — The most important maintenance task. We circulate a food-grade descaling solution through the heat exchanger to dissolve mineral buildup. This should be done annually in Arlington Heights (more frequently if you don't have a water softener). Cost: $150–$300.

Inlet Filter Cleaning — Tankless units have a small inlet water filter that catches sediment. We clean this during every service visit.

Venting Inspection — We verify the exhaust vent is clear, properly connected, and correctly sized.

Gas Pressure Check — We verify gas supply pressure meets the manufacturer's specifications. Low gas pressure is a common cause of ignition and performance issues.

Tankless Water Heater Repair Costs

Diagnostic Fee — $75–$150 (applied toward repair) Descaling/Flush Service — $150–$300 Ignition System Repair — $150–$400 Flow Sensor Replacement — $150–$350 Heat Exchanger Cleaning — $200–$400 Control Board Replacement — $300–$800 Gas Valve Replacement — $300–$600 Heat Exchanger Replacement — $800–$1,500+ (at this cost, replacement of the entire unit may be more economical if the unit is older)

Why Arlington Heights Chooses Plumbers 911 Chicago

Local Arlington Heights Experts

We understand Arlington Heights' residential plumbing infrastructure, from older homes near downtown to newer developments. Our plumbers know Cook County codes inside and out.

24/7 Emergency Response

Plumbing emergencies don't wait for business hours. Our Arlington Heights plumbers are available around the clock with fast response times throughout the 60004, 60005, and 60006 zip codes.

Upfront, Honest Pricing

We provide detailed written estimates before starting any work. No surprise charges, no hidden fees — just transparent, fair pricing on every job.

Licensed, Bonded & Insured

Every technician is State of Illinois licensed, bonded, and fully insured. We pull all required permits and ensure 100% code compliance.

Tankless Water Heater Repair FAQ — Arlington Heights

How often should I flush my tankless water heater?

In Arlington Heights, annual descaling is recommended. If you don't have a water softener and notice reduced hot water output, you may need flushing every 6–9 months. Regular flushing prevents scale buildup on the heat exchanger and extends the life of the unit.

My tankless water heater is showing an error code. What should I do?

Note the error code and check your owner's manual for the specific meaning. Some codes (like ignition failure) may resolve by resetting the unit. If the code persists or recurs, call us — we're familiar with error codes for all major brands and can diagnose the issue quickly.

Why does my tankless water heater give me cold water bursts?

This is called a "cold water sandwich" — it occurs when hot water left in the pipes from a previous draw is followed by a brief burst of cold water before the unit fires up again. It's common with short, repeated draws. A small buffer tank or recirculation system can eliminate this.

Is it worth repairing a 15-year-old tankless water heater?

It depends on the repair. Minor repairs ($150–$300) are usually worthwhile since the unit may still have years of life left. Major repairs like heat exchanger replacement ($800–$1,500) may not be cost-effective — at that point, a new unit with improved efficiency and a fresh warranty is often the better investment.