Tankless Water Heater Repair Solutions
Fast diagnostics. Expert fixes. Same-day service available.
Licensed & Insured
5-Star Rated
Same-Day Available
All Brands Serviced
Expert Diagnostics
Key Factors In Effective Tankless Heater Repair
A properly assessed repair can improve system operation while addressing the cause of recurring water-heating problems.
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Accurate Diagnostics
Identifying the actual fault helps prevent unnecessary part replacements and repeated service issues.
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Improved Water Flow
Clearing restrictions can help the heater activate correctly and maintain consistent performance.
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Stable Temperatures
Properly functioning sensors and controls help prevent unexpected temperature fluctuations.
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Electrical Inspection
Checking wiring and connections can identify problems affecting ignition and system operation
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Mineral Buildup Removal
Addressing scale accumulation helps protect heat-transfer components and maintain efficiency.
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Ignition Component Checks
Inspecting ignition-related parts helps ensure the burner activates safely and consistently.
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Component Replacement
Worn or damaged parts can be replaced when repair is necessary for reliable operation.
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Fewer Interruptions
Timely attention to developing issues can reduce unexpected loss of hot water.
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System Protection
Proper repairs help maintain the heater as an important part of the home's plumbing system.
Our Proven Process
Our 5-Step Diagnostic Process
We follow a proven, systematic approach to pinpoint the exact issue with your tankless unit.
Inspect System Condition
Check the unit, connections, controls, and visible components for signs of damage or wear.
Check Water Flow
Verify adequate water flow and identify restrictions that may prevent proper activation.
Evaluate Heating Performance
Test System response to determine whether the heater is heating correctly.
Identify Repair Needs
Determine whether cleaning, adjustment, component repair, or replacement is appropriate.
Expert Repair Solutions
Root Causes & How We Fix Them
Click any item below to see the likely symptom, repair action, and part replaced.
Faulty Igniter / Ignition Module
Likely Symptom: Unit won't ignite — clicks but no flame
Repair Action: Replace igniter electrode or ignition module
Typical Part Replaced: Ignition assembly
Failed Flow Sensor
Likely Symptom: No hot water — unit won't activate when taps are opened
Repair Action: Clean or replace the flow sensor
Typical Part Replaced: Flow sensor / turbine
Clogged Heat Exchanger
Likely Symptom: Error codes displayed, reduced heat output
Repair Action: Chemical flush and descale the heat exchanger
Typical Part Replaced: Heat exchanger (if cracked or corroded)
Blocked or Improper Venting
Likely Symptom: Unit shuts off mid-use or throws combustion errors
Repair Action: Clear obstructions and re-route vent if needed
Typical Part Replaced: Vent pipe fittings
Gas Valve Failure
Likely Symptom: No ignition, possible gas smell near unit
Repair Action: Replace the gas valve assembly
Typical Part Replaced: Gas valve assembly
Temperature Sensor Failure
Likely Symptom: Inconsistent water temperature — hot-cold swings
Repair Action: Replace the thermistor
Typical Part Replaced: Thermistor / temperature sensor
Printed Circuit Board (PCB) Failure
Likely Symptom: Error codes, no power, or erratic behavior
Repair Action: Reprogram or replace the control board
Typical Part Replaced: PCB / control board
Pressure Relief Valve Leak
Likely Symptom: Water dripping from the relief valve discharge pipe
Repair Action: Replace the pressure relief valve
Typical Part Replaced: T&P relief valve
Certified Brand Expertise
We Repair All Major Brands
Our technicians are trained on the specific quirks and error codes of every major manufacturer.
Rinnai
Navien
Noritz
Rheem / Paloma
Bosch
EcoSmart / Other Electric
Rinnai
Common Error Codes: Code 11 (ignition failure), Code 12 (flame loss), Code 25 (water temp too high)
Known For: Excellent reliability but scale-prone heat exchangers in hard-water areas like Knox County.
Rinnai requires OEM parts for warranty compliance.
Navien
Common Error Codes: E003 (ignition failure), E012 (flame loss), EO47 (low water pressure)
Known For: Built-in recirculation pump; condensate trap clogs are common on Navien units.
Navien units have a pre-filter that needs quarterly cleaning.
Noritz
Common Error Codes: Code 11 (no ignition), Code 90 (combustion abnormality), Code 73 (PCB failure)
Known For: Durable build quality, though gas valve failures are noted after 8–10 years of service.
Check venting configuration on older Noritz units — many Knoxville homes have outdated setups.
Rheem / Paloma
Common Error Codes: Code 13 (abnormal combustion), Code 29 (heat exchanger outlet sensor), Code C8 (scale buildup)
Known For: Budget-friendly, but heat exchanger scale is very common with Knox County's hard water.
Annual flushing is strongly recommended for Rheem units in the Knoxville area.
Bosch
Common Error Codes: A7 (overheating), EA (fan motor error), 1E (flame loss)
Known For: Compact units popular in condos; venting restrictions are a frequent cause of unexpected shutoff.
Bosch discontinued some residential lines — parts availability may vary on older models.
EcoSmart / Other Electric
Common Error Codes: No display, tripped breaker, heating element failure
Known For: 100% electric units with modulating elements — element failure is the #1 repair we see.
Element replacement is straightforward but requires a full system drain before service.
Don't wait for a cold shower.
Our Knoxville technicians are ready today.
Trusted Local Service
Why Knoxville Trusts Tankless Heater Pros
We've built our reputation on honest work and reliable service — every call, every time.
Same-Day Service
We dispatch technicians across Knox County daily — often within hours of your call.
All Brands & Models
Gas, propane, and electric tankless units. If it heats water, we fix it.
Upfront Pricing
No surprises. We quote before we wrench, so you know the cost before we start.
Licensed & Insured
TN-licensed plumbers with full liability coverage on every job.
Proudly Serving Our Community
Serving Knoxville & Surrounding Communities
We've built our reputation on honest work and reliable service — every call, every time.
Tankless Heater Pros proudly serves homeowners and businesses throughout Knox County and the surrounding East Tennessee communities. Whether you're in downtown Knoxville, the suburbs of Farragut, or across the county line in Maryville or Oak Ridge, our technicians are just a phone call away at (865) 407-1147
We understand the unique plumbing challenges of our region — from hard water mineral deposits common throughout the Tennessee Valley to the specific building codes and venting requirements in Knox County. That local expertise means faster, more accurate repairs for your tankless water heater.
Call (865) 407-1147 to confirm service in your area
Knoxville
Farragut
Hardin Valley
Karns
Cedar Bluff
Oak Ridge
Clinton
Lenoir City
Kingston
West Hills
Bearden
Sequoyah Hills
Northshore
Concord
West Knoxville
Maryville
Alcoa
Tellico Village
