Gas Tankless Water Heaters

Gas Tankless Water Heater Repair & Installation in Dallas–Fort Worth

Gas tankless water heaters deliver endless hot water, incredible efficiency and long-term reliability—making them the preferred option for many Dallas–Fort Worth homeowners. When properly installed and maintained, a gas tankless unit can last twice as long as a traditional tank heater while providing faster, cleaner and more consistent hot water. DFW Plumber offers expert gas tankless water heater installation, repair, replacement and descaling services throughout the DFW metroplex.

This page explains how gas tankless systems work, common repair issues, installation requirements, sizing, maintenance needs, venting options and frequently asked questions.

Why Choose a Gas Tankless Water Heater?

Gas tankless systems are ideal for homeowners who want uninterrupted hot water and higher efficiency. They heat water only when a fixture is turned on, eliminating standby heat loss and enabling near-instant endless supply.

• Endless hot water for showers, laundry and multiple fixtures
• Lower energy usage compared to tank heaters
• Up to 20+ years lifespan with proper maintenance
• Compact size and wall-mounted installation
• Reduced risk of flooding since there’s no storage tank
• Cleaner water with no rust or sediment sitting in a tank

Gas tankless heaters are especially beneficial for large households or homes with high hot-water demand.

Gas Tankless Brands We Install & Service

DFW Plumber installs and repairs all major tankless brands, including:

• Rinnai
• Navien
• Noritz
• Takahashi / Takagi
• Rheem Prestige & Performance Series
• Bosch Greentherm

We help select the correct model based on your home’s demand, gas supply, venting configuration and installation location.

Common Gas Tankless Water Heater Problems We Repair

Tankless units are advanced appliances with sensors, flow meters, fans, burners, heat exchangers and control boards. When one part fails, the entire system can suffer. DFW Plumber repairs all common tankless issues, including:

• No hot water due to ignition failure or burner issues
• Fluctuating temperatures caused by scale, flow issues or gas pressure
• Error codes from failed sensors, flame rods or control boards
• Reduced flow rate due to internal scaling
• Ignition failure caused by low gas pressure or dirty burners
• Venting blockages causing shutdowns
• Water too hot or too cold from faulty mixing valves or thermostats
• Combustion fan problems (common on older models)
• Internal leaks from heat exchangers or fittings

Most gas tankless systems are fully repairable when diagnosed early—especially ignition, sensor and scale-related issues.

Gas Tankless Installation Requirements

Installing a tankless heater requires proper gas sizing, venting, drainage and combustion air. DFW Plumber performs full system evaluations before installation.

1. Gas Supply Requirements

• High-BTU input lines needed—often ¾” or 1” lines
• Correct gas pressure for ignition and flow stability
• Dedicated shutoff valve near the unit

Undersized gas lines are the #1 reason tankless systems fail in North Texas.

2. Venting Requirements

• Category III stainless venting for many older models
• PVC concentric venting for condensing models (most modern units)
• Proper horizontal and vertical slope for safe exhaust
• Correct termination clearances from windows and doors

3. Drainage Requirements

• Condensate drain line for high-efficiency units
• Neutralizer installation where required

We handle permitting, code compliance and safe vent routing.

Sizing a Gas Tankless Water Heater

Proper sizing ensures you can run multiple fixtures at once without losing temperature. Sizing is based on:

• Gallons-per-minute (GPM) flow demand
• Number of simultaneous users
• Incoming water temperature
• Gas supply capability

DFW Plumber calculates your peak demand to ensure you receive endless hot water even during heavy usage.

Condensing vs Non-Condensing Tankless Systems

Condensing Models

• Most efficient option
• Use PVC venting
• Produce condensate requiring drainage
• Lower operating costs over time

Non-Condensing Models

• Use stainless venting
• Higher venting temperatures
• Often preferred for retrofit installations

We help homeowners choose the correct type for performance, efficiency and installation conditions.

Preventative Maintenance for Gas Tankless Units

Gas tankless water heaters require routine maintenance, especially in North Texas where hard water accelerates scale buildup.

• Annual descaling of the heat exchanger
• Cleaning the inlet screen filter
• Burner and combustion chamber cleaning
• Inspecting flame rods, sensors and igniters
• Checking venting & exhaust for blockages
• Condensate system cleaning (for condensing models)

Regular maintenance prevents error codes, ignition failure and temperature fluctuations.

When to Replace a Gas Tankless Water Heater

Replacement is recommended when you notice:

• Repeated ignition failures not related to gas supply
• Multiple sensor or control board failures
• Heat exchanger cracks or internal corrosion
• Frequent scale buildup despite flushing
• Age beyond 15–20 years
• Gas valve or burner failure on older units

Modern condensing tankless models offer major upgrades in performance and efficiency.

Frequently Asked Questions

Are gas tankless water heaters worth it?

Yes. They offer endless hot water, higher efficiency, longer lifespan and lower risk of flooding.

Why does my tankless heater shut off in the middle of a shower?

Common causes include scale buildup, undersized units, low gas pressure or dirty flame sensors.

Do tankless water heaters need maintenance?

Absolutely. Annual descaling and burner cleaning are essential for long-term reliability.

Can you retrofit a tankless heater where a tank heater used to be?

Yes—but it requires gas line evaluation, venting modifications and sometimes electrical adjustments.

Can you install a tankless heater I purchased myself?

Yes. We install all customer-provided units and ensure they meet code and venting requirements.

Does a tankless heater need a water softener?

It is strongly recommended in hard-water areas like North Texas to reduce scaling and extend system life.

For expert gas tankless water heater repair, installation and replacement anywhere in Dallas–Fort Worth, trust DFW Plumber. Visit DFWplumber.com to schedule your service today.