Full System Diagnostic
We test gas pressure, flow rate, outlet temperature, and check for error codes. The heat exchanger gets inspected with a camera. You get a written diagnosis and flat-rate price before we touch a wrench.
Fast, code-correct fixes for every major brand.
Tankless Water Heater Repair in Littleton, Colorado
When your on-demand unit quits, you need Tankless Water Heater Repair in Littleton that gets hot water back fast. We diagnose no-hot-water calls, error codes, and scale-related failures across Arapahoe County. Our licensed techs carry parts for Navien, Rinnai, and Rheem, so most repairs finish in one visit. Call for same-day service.
Careful work. Honest options.
About this service
Tankless Water Heater Repair in Littleton: What to Expect
Tankless Water Heater Repair in Littleton is the diagnostic and mechanical work required to restore a wall-mounted or outdoor on-demand unit that has stopped heating, started leaking, or thrown a fault code. Unlike tank systems, these units rely on a modulating gas valve, flow sensor, and heat exchanger that must be descaled and calibrated. We test each component with a multimeter and pressure gauge, then repair or replace only what failed.
Littleton's hard water and older housing stock push tankless units harder than most owners realize. Scale buildup in the heat exchanger is the top cause of reduced flow and cold-water sandwiches. If your tankless water heater is not heating, it is often a $200-$400 descaling and sensor fix, not a full replacement. We handle tankless water heater service Littleton homeowners call about most: no hot water, error codes, and leaking T&P valves.
- ✓ Same-Day Hot Water
- ✓ Scale-Focused Diagnosis
- ✓ Code-Correct Repairs
- ✓ Brand-Agnostic Expertise
What's included
What Our Tankless Water Heater Repair Includes
Every tankless repair visit covers a full diagnostic and the fix for the failed component. Here is what you get when you book us for tankless water heater repair in Littleton.
Failed Part Replacement
Igniters, flow sensors, thermocouples, gas valves, and thermostats get replaced on the spot when we have the part. We use OEM or equivalent parts and confirm the unit fires correctly before we leave.
Heat Exchanger Descaling
If scale is restricting flow, we run a descaling pump with manufacturer-approved solution for 45-60 minutes. This restores flow rate and temperature rise. It is the most common fix for Littleton's hard water.
Safety and Code Checks
We test the pressure relief valve, check for gas leaks, and confirm venting meets UPC standards. Electrical connections are checked per NEC. You get a safe, code-correct repair, not just a working unit.
Cleanup and Walkthrough
Drop cloths go down before we start and old parts leave with us. We walk you through what failed, why, and how to prevent a repeat. You get maintenance tips specific to your unit and water quality.
How it works
Our Tankless Water Heater Repair Process
When you call, we ask for the error code, unit brand, and when hot water stopped. That lets us load the right parts before we roll. Most calls get a 2-hour arrival window. If it is a 2 a.m. no-hot-water emergency, we dispatch immediately.
Our tech tests inlet and outlet gas pressure with a gauge, checks the flow sensor with a multimeter, and inspects the heat exchanger with a camera. You get a written diagnosis and a flat-rate repair price before we start. Diagnosis takes 30-45 minutes.
If scale is the issue, we run a descaling pump with manufacturer-approved solution for 45-60 minutes. If a part failed, we replace the igniter, gas valve, thermostat, or heating element on the spot. Most repairs finish in 1-3 hours total.
We fire the unit, run hot water at multiple fixtures, and verify temperature rise meets spec, usually 35-50 degrees above inlet. We check for gas leaks and confirm the pressure relief valve holds. You see the numbers before we pack up.
We lay drop cloths, haul away old parts, and walk you through what failed and why. You get a written summary and maintenance tips to prevent a repeat call. If a follow-up visit is needed, it is on us within the warranty window.
STEP 01Phone Triage
When you call, we ask for the error code, unit brand, and when hot water stopped. That lets us load the right parts before we roll. Most calls get a 2-hour arrival window. If it is a 2 a.m. no-hot-water emergency, we dispatch immediately.
Tools & methods
Tools and Methods We Use
Descaling Pump
Circulates manufacturer-approved solution through the heat exchanger to dissolve scale. This is the primary fix for Littleton's hard-water buildup and restores flow rate in 45-60 minutes.
Multimeter
Tests continuity and voltage on flow sensors, thermostats, heating elements, and control boards. It confirms which component failed before we replace anything.
Pressure Gauge
Checks inlet and outlet gas pressure and system water pressure. Correct pressure is required for the unit to fire and for the T&P valve to hold.
Inspection Camera
Lets us see inside the heat exchanger and venting without disassembling the whole unit. We confirm scale, corrosion, or blockages before quoting a repair.
Thermostat Tester
Verifies thermostat calibration and outlet temperature sensor accuracy. A thermostat out of spec causes scalding water or no heat at all.
Anode Rod Socket
Removes and installs anode rods on tank units during maintenance or repair. A spent anode rod means the tank is starting to corrode from the inside.
Real results
Before and after.
Tankless Water Heater Repair
Navien Unit Restored After Scale Buildup
A Ken Caryl homeowner had cold-water sandwiches and reduced flow for weeks. The Navien unit was firing but not reaching setpoint. Two other plumbers quoted a full replacement at $2,800.
After: We descaled the heat exchanger, replaced a clogged flow sensor, and verified temperature rise at 45 degrees above inlet. Total cost was $420. The unit has run steady for months since.
Book this service →
Tankless Water Heater Repair
Rinnai Error Code Fixed Same Day
A Downtown Littleton home had a Rinnai throwing a code 11 for two weeks. No hot water, and the homeowner was showering at a neighbor's house. The unit would not fire at all.
After: We diagnosed a failed igniter and a dirty flame sensor. Both were replaced in under two hours. The unit fired on the first try and has run without codes since. Cost was $310.
Book this service → Tankless Water Heater Repair
Leaking T&P Valve Stopped in Roxborough
A Roxborough homeowner noticed water pooling under the tankless unit. The T&P valve was weeping constantly, and pressure was running high. The expansion tank had failed.
After: We replaced the T&P valve and installed a new expansion tank charged to match system pressure. The leak stopped immediately and pressure held in range. Total cost was $480.
Book this service → Problems we solve
Tankless Problems We Fix in Littleton
Most tankless failures fall into a handful of categories. Here is what we see most and how we fix it.
Ask a pro →No hot water or cold-water sandwiches
We test flow rate and temperature rise, inspect the heat exchanger for scale, and check the flow sensor. Most cases resolve with descaling and a sensor replacement. You get steady hot water the same day.
Error codes on the display
We pull the code, test the related component, and replace what failed. Common codes trace to igniters, flame sensors, and gas valves. We clear the code and confirm the unit runs through a full heating cycle.
Water leaking from the unit or T&P valve
We locate the leak, test system pressure, and replace the failed T&P valve or fitting. If an expansion tank is missing or failed, we install or recharge one. The leak stops and pressure stays in range.
Unit will not ignite or stay lit
We test the igniter, thermocouple, and gas valve, then replace the failed part. Every gas repair includes a leak check and a confirmation that the burner lights and holds reliably.
Proof you can check
Licensed, Certified, and Reviewed
- Colorado Master Plumber License · State of Colorado
- NATE Certification · North American Technician Excellence
- EPA Lead-Safe Certification · U.S. Environmental Protection Agency
- Backflow Prevention Certification · State of Colorado
- OSHA 10 Certification · Occupational Safety and Health Administration
Most repairs run $180 to $650 in 2026, depending on the failed part and whether descaling is needed. A flow sensor or igniter replacement sits at the low end. A gas valve or heat exchanger service pushes toward the top. We quote flat-rate before work starts, so you approve the number first.
The top three causes we see are scale buildup in the heat exchanger, a failed flow sensor, and a dirty or failed igniter. Littleton's hard water accelerates scale, which restricts flow and triggers error codes. Cold-water sandwiches and reduced temperature rise usually point to scale. A diagnostic visit confirms it in under an hour.
Littleton Plumbing Solutions repairs all major tankless brands, including Navien, Rinnai, Rheem, Noritz, Bosch, and Takagi. Our techs are NATE Certified and hold a Colorado Master Plumber License. We carry parts for same-day fixes and serve Arapahoe County addresses including Ken Caryl, Bow Mar, and Roxborough.
Yes, most same-day tankless water heater repair Littleton Colorado calls finish in one visit. We stock common failure parts on every truck, so igniters, flow sensors, and thermocouples get replaced on the spot. If a rare part is needed, we tell you the ETA before we leave and schedule the return.
Ready when you are
Get Tankless Water Heater Repair in Littleton Today
No hot water is not something to wait on. We run 24/7 dispatch, carry parts for same-day fixes, and quote flat-rate before we start. Call now and get a licensed tech to your Littleton address fast.
Book a Repair +13038790886 →
Request an appointment
Contact Littleton Plumbing Solutions
Call us at +1 303-879-0886 or send an email to info@littletonplumbingsolutions.com. We answer the phone 24/7 for emergencies and book regular service Monday through Friday. Most calls get a same-day slot, and we will give you a real arrival window, not a four-hour block.
Call anytime+13038790886Email the officeinfo@waterheaterrepairlittleton.com
Office hoursOpen 24 hours · 7 days a week