Tankless Water Heater Repair in Houston | We Speak "Error Code"

Licensed Master Plumbers (MPL-38162). A tankless heater is a computer that heats water. When it fails, you don't need a handyman; you need a certified technician.

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Schedule Your Repair – Call (281) 427-8325

INTRODUCTION (The Diagnostic Hook)

Unlike a traditional tank that is just a big kettle, your Tankless Water Heater is a sophisticated machine with circuit boards, flow sensors, and combustion fans. When it breaks, most standard plumbers scratch their heads and suggest a replacement.

At Blackmon Plumbing, we are Factory-Trained on Navien, Rinnai, and Rheem systems. Whether you have a “Cold Water Sandwich” (fluctuating temperatures) or a flashing error code on the display, we diagnose the root cause accurately. We arrive in Mobile Warehouses stocked with igniters, flame rods, and descaling pumps to get your hot water back today.

Decoding the Error Codes

Before you call, check the digital display on the front of the unit.

Error 11 (Ignition Failure)

The unit tries to light but fails. Often caused by a dirty flame sensor or—more commonly—an undersized gas line.

Error 12 (Flame Loss)

The fire lights but goes out. Often caused by intake/exhaust blockage (birds nesting in the vent).

Error LC (Scale Buildup)

The unit senses calcification in the heat exchanger. It needs a flush immediately.

The #1 Killer: Hard Water & Scale

Houston water is mineral-heavy.

The Problem: Calcium builds up inside the tiny copper or stainless steel tubes of your heat exchanger. This acts like insulation, forcing the burner to work harder until the metal overheats and cracks.

The Fix (Descaling): We perform a professional Distilled Vinegar Flush. We hook up a circulation pump to your isolation valves and cycle a cleaning solution through the unit for 45 minutes to dissolve the rock-hard scale.

Repair vs. Replace: The 50% Rule

When is it worth fixing?

Repair It: If the unit is under 10 years old and the issue is a sensor, igniter, or fan. These are affordable parts.

Replace It: If the Heat Exchanger is leaking. This is the engine of the car. If it cracks (and is out of warranty), the labor and part cost usually exceed 50% of the price of a new unit.

Maintenance: The Annual Flush

Manufacturers require annual maintenance to keep your warranty valid. Our Tankless Tune-Up includes:

Descaling: Flushing the heat exchanger.

Filter Cleaning: Cleaning the cold water inlet screen (often clogged with sediment).

Combustion Check: Verifying gas pressure and exhaust safety.

Why Choose Blackmon for Tankless?

Parts on the Truck: We don’t have to order a standard Navien igniter; we usually have it.

Gas Expertise: Half of “broken” tankless units are actually just “starved” units. We verify your gas pressure is adequate (dynamic vs. static pressure).

Warranty Support: As authorized service providers, we can often process warranty claims for parts (you just pay for labor).

Common Repair Questions

Q: Why does my water go cold in the middle of a shower?

A: This is often a Flow Sensor issue. The unit thinks you turned off the tap, so it shuts down the burner. It’s a quick fix.

Q: How much does a flush cost?

A: We offer a flat-rate price for descaling. It is significantly cheaper than replacing a heat exchanger.

Q: My unit is making a loud rumbling noise.

A: This is called “kettling.” It means scale has built up inside the pipes, trapping steam. You need a flush immediately to prevent a rupture.

Q: How often should I have my tankless water heater serviced?

A: Annually. Houston’s hard water accelerates scale buildup. Manufacturers require yearly maintenance to keep warranties valid. We offer maintenance plans with automatic scheduling.

Q: Can you repair any brand of tankless water heater?

A: We specialize in Navien, Rinnai, and Rheem—the most common brands in Houston. We’re factory-trained on these systems and stock their parts. For other brands, we can diagnose and order parts as needed.

Get Your Hot Water Back

Don’t take cold showers. Call the tankless tech experts.

Dispatch a Technician – Call (281) 427-8325

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