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Call and describe the symptoms.
Tell us what the unit is doing, the brand and any error code on the display. The details help us plan the diagnostic visit.
Tankless water heater repair in Houston
An error code is a clue.
We find the part behind it.
Factory-authorized for Rinnai, Navien, Noritz, Takagi and Rheem.
Gone cold in the middle of a shower? A code blinking that wasn’t there yesterday? Water swinging between scalding and lukewarm when someone opens another faucet? Houston’s dedicated tankless repair team has the diagnostic tools, the training and the OEM parts to fix your unit correctly the first time, and we finish most repairs in a single visit.
Navien NPE-A2 series
Read the code correctly.
Rinnai uses numbers, Navien uses E-codes and Noritz uses two-digit codes. We trace each one to the component that failed instead of clearing it and hoping.
Most fixed in one visit.
Our technicians carry the most common OEM parts on every truck, so most tankless repairs are finished in a single visit.
Repair with a warranty.
Every tankless repair is backed by a 1-year parts and labor warranty, plus the manufacturer’s warranty on the parts we replace.
Every repair starts with a full diagnostic.
A tank simply heats and holds water. A tankless unit is a computer-controlled appliance with multiple sensors, a control board and precision components that all have to work in concert. When one part drifts out of specification, the onboard computer shows an error code and shuts the system down to prevent damage. That shutdown protects the unit, and it means you need someone who reads the code correctly instead of clearing it and hoping for the best.
Test the whole system.
We test gas pressure at the manifold, measure incoming and outgoing water temperatures (Delta-T), check the electrical connections, inspect the heat exchanger for scale and verify the venting. That way we fix the root cause along with the symptom.
Know each brand inside out.
A Rinnai RUR199iN and a Navien NPE-240A have completely different internal architectures, error code systems and failure patterns. Our technicians complete factory training for each brand we service every year, and we work directly with manufacturer technical support on complex cases.
Act before it gets expensive.
The longer a faulty unit keeps running, the more the eventual repair costs. A $165 flame rod replacement today can become a $600 control board failure next month if the root cause isn’t addressed.
The tankless problems we fix every day.
We solve the issues other plumbers can’t diagnose. A general plumber sees a tankless error code, guesses at the problem and immediately recommends a $5,000 replacement. Our team sees the same code and knows exactly which component failed, why it failed and how to fix it. These are the repairs we make most often across Houston, with typical prices.
Heat exchanger descaling: $195 to $250
Houston’s hard water leaves calcium and magnesium deposits inside the heat exchanger. They reduce efficiency and cause temperature swings. Using commercial-grade descaling equipment, we flush the system with a commercial-grade descaling solution, monitor pH throughout and check flow rates before and after to confirm the unit is fully restored.
Flame rod cleaning: $100 to $175. Replacement: $165 to $275
The flame rod confirms to the control board that a flame is present. When it corrodes or builds up carbon, the unit fails to ignite or shuts down mid-cycle. We clean the rod or replace it with a genuine OEM part, then recalibrate the ignition sequence.
Ignition and gas valve failures: $200 to $450
If the unit clicks but won’t light, or lights and shuts off straight away, the cause is usually the igniter, the gas valve or the flame sensor. We test each part on its own and replace only what has failed.
Flow sensor and thermistor problems: $165 to $275
Inconsistent temperatures and “cold water sandwiches” often come from a failing flow sensor or thermistor, the parts that detect water flow and read the temperature. We replace them with OEM parts and recalibrate the system.
Control board diagnosis and replacement: $300 to $600
The control board is the brain of the unit. When it fails, you may see several error codes, intermittent shutdowns or a complete loss of function.
Why tankless units fail in Houston.
Tankless water heaters are engineered for 20+ years of service, but Houston’s hard water works against them. Mineral scale coats the heat exchanger, restricts flow and makes the unit work harder until it triggers a safety lockout. A Rinnai flashing code 11, a Navien showing E003 or a Noritz that won’t ignite is the system asking for professional attention now, not next week.
TANKLESS REPAIR PRICING
Most repairs: $150 to $600
Typical Houston tankless repairs. The flat diagnostic fee is applied to the repair if you go ahead.
What sets the
repair price?
Mostly, the part that failed. Flame rod cleaning runs $100 to $175, descaling $195 to $250, a flame rod replacement or a flow sensor $165 to $275, ignition and gas valve repairs $200 to $450, and a control board $300 to $600. You get a transparent quote after the diagnosis, before the repair starts.
Every tankless repair is backed by a 1-year parts and labor warranty, plus the OEM warranty on the replaced components. Call 832-673-0909 to book a diagnostic visit.
From the first call
to a tested repair.
Four steps, with a quote before the repair and a performance test after it.
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Diagnostic visit.
We test gas pressure, Delta-T, electrical connections, scale in the heat exchanger and the venting to find the root cause.
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Transparent quote, OEM repair.
You see the price before we start. We replace only what has failed, with genuine OEM parts, and recalibrate the system.
04
Test and verify.
We measure flow rate and Delta-T before and after the repair to confirm the unit is performing as it should.
The brands
we repair.
We are factory-authorized to service Rinnai, Navien, Noritz, Takagi and Rheem tankless systems. That also lets us process warranty claims that general plumbers can’t.
We carry the most common OEM parts on every truck, and we replace flame rods, control boards, igniters, gas valves, flow sensors and thermistors with genuine OEM parts.
Repair or replace?
We do the math with you.
Tankless systems are designed to last 20+ years, so a mid-life repair typically delivers an excellent return. If your unit is under 10 years old and the repair costs less than 50% of a replacement, repair is almost always the better investment.
A 15+ year old unit with a major component failure, like a cracked heat exchanger, is different. Replacement may make more financial sense, and we’ll walk you through the numbers honestly. We never pressure anyone into a replacement. That isn’t how we earned 1,400+ five-star reviews.
Serving Greater Houston.
Confirm the service address and project with the team. Some areas are subject to an additional travel fee.
Good questions about tankless repair.
What does a tankless water heater error code mean?
Error codes are your unit’s built-in diagnostic system, and each brand uses its own. Rinnai uses numeric codes, such as 11 for an ignition failure. Navien uses E-codes, such as E003 for ignition. Noritz uses two-digit codes. Instead of clearing the code and hoping it doesn’t return, we trace it to the component that failed, whether that is a flame rod, gas valve, flow sensor or control board, and repair the root cause.
How much does tankless water heater repair cost in Houston?
Tankless repairs in Houston typically cost $150 to $600, depending on the problem. Common repairs include flame rod cleaning ($100 to $175), heat exchanger descaling ($195 to $250), ignition and gas valve repairs ($200 to $450) and control board replacement ($300 to $600). Our flat diagnostic fee is applied to the repair cost if you choose to go ahead.
Can you repair all brands of tankless water heaters?
Yes. Hot Water Guys is factory-authorized to service Rinnai, Navien, Noritz, Takagi and Rheem tankless systems. We carry the most common OEM parts on every truck and work directly with manufacturer technical support teams on complex cases. Being factory-authorized also means we can process warranty claims that general plumbers can’t.
Should I repair or replace my tankless water heater?
If your unit is under 10 years old and the repair costs less than 50% of a replacement, repair is almost always the better investment. Tankless systems are designed to last 20+ years, so a mid-life repair typically delivers an excellent return. If your unit is 15+ years old with a major component failure, like a cracked heat exchanger, replacement may make more financial sense. We’ll walk you through the math honestly, and we never pressure anyone into a replacement.
Why is my tankless water heater not producing hot water?
The most common causes are an ignition failure (often a corroded flame rod or a gas supply problem), an error code that has locked the unit out, or heavy scale blocking the heat exchanger. Other possibilities include a failed flow sensor that doesn’t detect water demand, electrical problems and blocked venting. We test each component in turn to find the exact cause instead of guessing.
Error code
on the display?
Tell us the code and what the unit is doing. Most repairs land between $150 and $600, and you see the quote before we start.