Tankless Water Heater Repair in Madison
Three Generations of Plumbing Experience, Serving Madison, Wisconsin Since 1983
Arndt & Son Plumbing has been serving Madison, Wisconsin since 1983. As a fully licensed and insured, family-owned plumbing company, we repair tankless water heaters for residential and commercial customers throughout the area. Tankless units heat water on demand rather than keeping a tank continuously hot, which makes them efficient but also means the components handling ignition, flow, and heat exchange work harder with every use.
An error code, a sudden loss of hot water, or rising utility bills can all point to a problem worth addressing before it gets worse. Call us at (608) 530-1301 to schedule tankless water heater repair or request a free estimate.
Signs Your Tankless Water Heater Needs Repair
Some symptoms are obvious. Others are easy to dismiss until the problem grows. Here are the common signs that a tankless unit needs professional attention:
- No hot water or hot water that cuts out mid-use: These patterns typically point to an ignition failure or a heating component that isn’t firing consistently.
- Displayed error codes: Tankless units use onboard sensors to detect faults, including ignition, venting, flow, and overheating issues. Each code is manufacturer-specific and points to a different part of the system.
- Cold water sandwich: A brief burst of cold water interrupting otherwise hot output can occur without triggering any error code, but it still signals a timing or flow issue worth diagnosing.
- Inconsistent water flow: If the unit can’t meet its minimum flow rate threshold, it won’t fire. A clogged aerator or a partially open fixture is often the cause.
- Rising energy bills: A unit working harder than it should due to internal buildup or a failing component can show up in your utility costs before it fails completely.
Common Causes of Tankless Water Heater Problems
Diagnosing a tankless unit correctly means understanding what’s behind the symptom, not just resetting the display. Three causes account for a large share of the failures we see.
Ignition & Venting Faults
Ignition failures are commonly traced to a low or closed gas supply, a failing igniter, or a dirty flame sensor. Venting problems are a separate concern: debris, ice accumulation, or nesting material can block the flue and trigger a safety shutdown. A blocked vent that allows the unit to keep running is also a carbon monoxide risk, which is why these fault codes shouldn’t be bypassed without a professional inspection.
Mineral Scale Buildup in Madison’s Hard Water
Madison’s tap water is classified as very hard, with hardness levels of roughly 16 to 24 grains per gallon from calcium and magnesium in the local groundwater. Scale forms more readily in hot water systems than cold, and the heat exchanger inside a tankless unit is particularly vulnerable. As scale accumulates, it reduces heating efficiency and can trigger overheating-related fault codes. Periodic descaling is worth scheduling for most households running a tankless system in this area.
Repair or Replace?
A unit with one isolated issue is usually a good candidate for repair. A unit with recurring failures across multiple components may cost less to replace over time. Professional diagnosis makes that call clearer: an error code that looks serious can sometimes trace back to a blocked vent or a dirty inlet filter, while a code that looks minor can reflect internal component damage. Persistent combustion or venting fault codes should be inspected before the unit is reset, not after.
Why Madison Property Owners Call Arndt & Son Plumbing
Three generations of our family have been doing plumbing work in this community. That history means we’ve worked on traditional systems and modern tankless units alike, and we carry full licensing and insurance on every job.
Superior-Quality Materials
We use superior-quality materials on every repair so the work holds up and looks right.
Respect for Your Property
Our technicians wear shoe covers, lay down protective rugs, and clean up thoroughly before they leave.
Fair & Transparent Pricing
We offer free estimates so you know what you’re looking at before any work begins.
Serving Madison & the Surrounding Region
We provide tankless water heater repair throughout the Madison area and the surrounding communities, including Brooklyn and Fitchburg. Our service area covers Dane County, Rock County, and Green County. If your tankless unit is showing problems, we’re the local team to call.