Before
After
4 Navien tankless water heater replaces a corroded tank in Greenville
A corroded tank water heater replaced with a Navien NPE-240A2 tankless unit in the crawl space.
See the full jobTankless repair
Tankless water heater repair in Greenville and the Upstate
Tankless water heater repair for error codes, cold-water sandwiches and units that shut off mid-shower. Most problems are fixable, and many start with scale.
A licensed Master Plumber on every job
Why does my tankless water heater keep shutting off?
The most common causes are mineral scale in the heat exchanger, a dirty inlet filter, low gas supply, a venting problem or a failing flow sensor. Ethical Plumbing reads the error code, finds the cause and shows you the repair with a written price. Call 864-438-0525.
- Gas and electric tankless
- Descaling and flushing
- Error code diagnosis
- Flow and flame sensors
Most tankless problems come down to a few causes
Tankless water heaters are reliable, but they are more sensitive than a tank. Mineral scale, a clogged filter or a small drop in gas pressure can trip a safety shutoff that a tank would ignore. The good news is that these are usually repairs, not replacements.
Most units show an error code when something goes wrong. We read the code, check the gas supply, venting, filters and sensors, and look at how the unit was installed. A surprising number of problems come from undersized gas lines or missing service valves from the original install.
If the unit is near the end of its life, or the repair would cost more than it is worth, we tell you and show you the price of a new tankless unit alongside the repair.
Signs your tankless heater needs service
Call when you notice any of these:
- An error code on the display
- Hot water that turns cold mid-shower
- Hot and cold bursts (a cold-water sandwich)
- Lower hot water flow than before
- The unit will not ignite
- Unusual noises when hot water runs
What we repair most often
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Scale buildup
Minerals coat the heat exchanger and trigger overheat and flow errors. Descaling usually clears it.
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Inlet filters
A clogged water filter reduces flow until the unit will not fire.
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Ignition and flame sensors
Dirty or failing sensors stop the burner from lighting or staying lit.
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Flow sensors
If the unit cannot sense water moving, it will not heat.
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Venting faults
Blocked or improperly installed vents trigger safety shutoffs.
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Gas supply
An undersized gas line starves the unit when several fixtures run at once.
Tankless units in Upstate homes
On soft city water, scale builds slowly, but it still builds. Homes on private wells see it much faster. A yearly flush through the service valves is the single best thing you can do for a tankless unit, and it is included in the VIP Prevention Plan safety inspection.
What affects the price of a tankless repair
You get a written price before any repair starts. It depends on:
- Whether descaling clears the fault
- Which part has failed
- Whether service valves need to be added
- Gas line or venting corrections
Tankless water heater flushing and descaling
Most tankless problems start with mineral scale. A yearly flush runs a descaling solution through the heat exchanger, cleans the inlet filter and checks the burner and venting. It takes about an hour when service valves are installed, and it is the best way to keep a tankless unit running for 20 years.
How a visit works
You book a time
Online or by phone. We confirm your arrival window and call when the plumber is on the way, or text or email if we cannot reach you.
We find the cause
A licensed Master Plumber diagnoses the problem and explains it in plain terms.
You choose, in writing
You get your options side by side with written prices. Nothing starts until you approve.
We fix it and walk you through it
Clean work area, tested result, and a walkthrough before we leave.
Recent tankless water heater repair jobs
Before
After
4 
3 Tankless water heater swap in Greenville
An existing tankless water heater replaced with a new Navien unit, with clean, serviceable piping.
See the full jobWhy homeowners call Ethical Plumbing for tankless repair
Every job starts with a diagnosis from a licensed Master Plumber, not a sales pitch. We explain what we found in plain terms, show you the options side by side, and put the prices in writing before anything starts. If a repair makes more sense than a replacement, we say so.
We treat your home like a job site that people live in: shoe covers on, work area protected, cleaned up before we leave, and a walkthrough of what we did. Ethical Plumbing has served the Upstate for 16+ years, and our team brings 100+ years of combined plumbing experience. You can meet our plumbers or read what customers say.
What customers say
Every review here is from a real customer. Names are shortened for privacy.
Google
They exchanged our old water heat tank with a tankless water heater and repiped the crawl space. Ivan and Asher did the whole work within less than two days. We felt treated with respect, everything was explained well and they left everything clean.
Tankless water heater repair across the Upstate
We repair tankless water heaters in 7 counties across the Upstate and western North Carolina. Towns with a local page are linked.
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Greenville County, SC
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Spartanburg County, SC
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Pickens County, SC
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Anderson County, SC
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Henderson County, NC
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Polk County, NC
- Tryon
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Transylvania County, NC
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Also serving
- Seneca, SC
- Gray Court, SC
Tankless water heater repair FAQs
Do you repair Navien and Rinnai tankless water heaters?
Yes. We are Navien certified and also service Rinnai and other major brands, gas and electric.
What is a cold-water sandwich?
A short burst of cold water between hot, usually when you turn the tap off and on again. It is normal for tankless to some degree; a recirculation pump or a small buffer tank reduces it.
How often should a tankless water heater be flushed?
Once a year is a good rule on city water. Homes on well water, or with hard water, may need it every six months.
Can I descale my tankless unit myself?
If service valves were installed, many homeowners can. Without them, the job requires cutting into the lines, so call us.
Why is my tankless showing an error code?
Codes point to the system that tripped, such as ignition, flow, overheat or venting. The code tells us where to start, not always the root cause.
Is it worth repairing an older tankless unit?
Usually, if the heat exchanger is sound. If the exchanger is leaking or badly scaled after years without service, replacement may make more sense.
Why does my hot water flow seem weak?
A clogged inlet filter or scale in the heat exchanger restricts flow. Cleaning the filter and descaling usually restores it.
Do you repair all tankless brands?
Yes. We diagnose and repair tankless units from all major manufacturers, gas and electric.
Can a tankless unit freeze?
Units on exterior walls can freeze if power is lost during a hard freeze. Most have freeze protection that needs power to work.
Ready when you are
Tell us what's going on.
A Master Plumber will find the cause, explain it in plain terms, and put your options in writing before any work starts.
- A licensed Master Plumber on every job
- Serving the Upstate for 16+ years
- Written prices, every job