Rinnai Code 11
Code 11 generally indicates that the unit attempted to ignite but did not establish a flame. Diagnosis may involve the gas supply, ignition and flame-sensing components, venting, wiring, or controls.
Code 11 Diagnosis & Repair
Irvine Tankless Flush Specialist · Based in Woodbury
Tankless Water Heater
Flush Service in Irvine
$150 professional tankless water heater flushing in Irvine. October promotion: $125 when service is completed by October 31, 2026. Remove scale buildup, maintain efficiency, and help extend system life.
$150
Standard tankless flush · Typically 1–1.5 hours
October special: save $25
October special: save $25
All major brands
Rinnai
Navien
Noritz
Rheem
5 stars on Google
★★★★★
Voted Nextdoor
Neighborhood Fave
17+ Years
Experience
Trusted by Realtors
& Homeowners
No hot water or a tankless error code?
Call or text to request tankless diagnosis and repair in Irvine.
Tankless Water Heater Repair
$150 standard · $125 October special
What's Included in the $150 Tankless Flush
Standard tankless water heater flush service includes connecting a recirculating pump, circulating descaling solution through the system, helping remove mineral scale buildup, cleaning the inlet filter when accessible, checking flow during the flush, and returning the unit to normal operation.
Repairs, diagnostics, replacement parts, stuck valves, missing service valves, or unusual access issues are quoted separately.
The Problem & The Fix
Why Routine Tankless Flushing Matters
Minerals in the water can accumulate inside a tankless heat exchanger over time. The rate varies with local water conditions, treatment, usage, and the unit itself. Here's what routine descaling addresses.
Without Appropriate Maintenance
Hard-water minerals such as calcium and magnesium can accumulate inside the heat exchanger. Without appropriate maintenance, that scale may become more restrictive over time.
- Reduced hot water flow & pressure
- Higher energy bills from lost efficiency
- Strange popping or rumbling noises
- Recommended maintenance may be missed
- Increased risk of scale-related performance problems
- Premature system replacement
With Routine Flushing
A professional descaling flush removes mineral buildup from the water circuit and helps keep routine maintenance current.
- Mineral scale removed from the water circuit
- Inlet filter cleaned when accessible
- Flow and restart checked after service
- Completed maintenance documented
- Scale-related restrictions may improve
- Supports more reliable long-term operation
Real Results
What Hard Water Is Doing Inside Your Tankless Water Heater
Images from real service calls in Irvine and Lake Forest. The amount of scale varies by unit, water conditions, treatment, usage, and maintenance history.
What comes out of a heavily scaled tankless.
You're overdue for a flush when there is mineral buildup around the inlet filter.
What a flush pulls out — sediment and mineral buildup
Why It Matters
How Routine Descaling Helps
What a professional flush can—and cannot—do for your system.
✓
Maintenance Documented
Many manufacturers recommend periodic maintenance. A service receipt documents completed work, but warranty requirements and coverage vary by manufacturer, model, and installation.
✓
Removes Mineral Buildup
A tankless water heater flush removes scale from inside the heat exchanger, helping maintain heating efficiency and hot-water flow.
✓
Supports Reliable Operation
Routine maintenance helps reduce avoidable scale accumulation and may support longer, more reliable service life.
✓
Helps Prevent Costly Breakdowns
Mineral buildup can cause overheating and damage the heat exchanger, leading to costly repairs or early replacement. Routine flushing removes that buildup to help prevent premature, scale-related breakdowns.
Dustin Swad
Owner — Ultra Home Repair
Why Dustin
17+ Years of Hands-On Experience
With 17+ years in construction and home renovation, I understand how homes work and what matters to homeowners. Tankless water heater maintenance isn't a sideline — it's a core specialty I've invested in deeply.
I specialize in diagnosing and maintaining tankless systems across Irvine's neighborhoods — including Woodbury, Orchard Hills, Great Park, and Northwood — as well as Lake Forest and nearby communities.
Ultra Home Repair is locally owned and operated. Contact me directly to discuss your unit, the work involved, and your questions before scheduling.
No sales pressure. No unnecessary replacements. No commissioned upsells. Just honest maintenance and a flat price you know before I show up. If your unit doesn't need additional work, I tell you that — and you go on with your day.
- Tankless Flushing Specialist
- 17+ Years Hands-On Experience
- All Major Brands Serviced
- Trusted by Irvine & Lake Forest Neighbors
- Detailed Service Documentation Provided
The Service
What Happens During a Flush
A complete service visit takes about 1–1.5 hours. Here's the process I run on every unit.
1
System Inspection
I check the brand, model, and connections, look for signs of leaks or corrosion that could indicate a slow leak, and assess the degree of mineral buildup before starting.
2
Setup & Isolation
I shut off the gas and water supply, connect to the unit's isolation valves, and stage the descaling pump, hoses, and reservoir for a clean, contained flush.
3
Heat Exchanger Descaling
I circulate the manufacturer-appropriate descaling medium through the heat exchanger for the time specified by the applicable unit and product instructions. Some manufacturers specify white vinegar; others permit an approved descaler.
4
Inlet Filter Cleaning
I remove and clean the cold water inlet filter to restore full flow into the unit. If the filter is damaged, replacement is available for an additional charge.
5
Rinse & Restart
I flush remaining descaling solution from the system, restart the unit, confirm proper ignition, and verify temperature output at the fixture.
6
Service Documentation
You receive an emailed receipt detailing the work performed — useful for your records, manufacturer warranty claims, and future maintenance scheduling.
Professional-Grade Service
What a Proper Flush Requires
Some homeowners can perform routine flushing when the unit has service valves and they follow the exact manufacturer instructions. Professional service is useful when access, the model-specific procedure, filter service, or the shutdown and restart sequence is uncertain.
Submersible Descaling Pump
A recirculating pump sized for the procedure moves the selected descaling medium through the heat exchanger in a controlled loop.
5/8" Service Hoses
Heat-rated lines with proper fittings to connect securely to your unit's isolation valves without leaks or pressure loss.
Manufacturer-Appropriate Descaling Medium
Rinnai's published procedure specifies undiluted white vinegar, while other manufacturers may permit an approved descaler. The unit's model instructions control the method used.
Filter Service Tools
Specialized tools for safe inlet filter removal without damaging the manifold or cross-threading the housing on reinstall.
Beyond equipment: a proper flush requires knowing how to safely isolate and depressurize the system, circulate and rinse the selected medium, service the inlet filter, and restart the unit in the correct sequence. Manufacturer instructions and warranty terms vary by brand and model.
$150 standard · Save $25 in October
What You Get for $150
No upsells, no surprise charges, no "while I'm here" add-ons. One flat price, every time.
- Pre-flush system inspection — including leak and corrosion check
- Heat exchanger descaling with the manufacturer-appropriate medium and procedure
- Professional-grade equipment: submersible descaling pump, service hoses, calibrated reservoir
- Cold water inlet filter removal and cleaning
- Post-flush rinse and system restart verification
- Detailed emailed service receipt for your records and warranty
- 90-day workmanship warranty
- Standard flush: $150; October special: $125 for service completed by October 31, 2026. Existing scope and exclusions apply.
Want to confirm the $150 service applies to your unit?
Text a photo of the heater and your ZIP code. Dustin will confirm the brand, access, and service area before scheduling.
Text a Photo to DustinLocal Hard Water
Tankless Water Heater Maintenance for Irvine Homes
Irvine Ranch Water District explains that water hardness varies by source, location, and season. That is why the right maintenance interval should be based on the unit manual, actual water conditions, treatment, and usage—not a one-size-fits-all promise. See IRWD's 2026 Water Quality Report.
Flush · Clean · Descale
Tankless Water Heater Cleaning, Descaling & Maintenance
Homeowners use different terms — tankless water heater flush, tankless cleaning, tankless descaling, or annual tankless maintenance — but they usually refer to the same core service: circulating a descaling solution through the unit to remove mineral buildup from hard water. In Irvine and Lake Forest, this is especially important because hard water can reduce efficiency, restrict flow, and shorten the life of the system.
Warning Signs
Signs Your Tankless Water Heater Needs Flushing
If you notice any of these issues, your tankless system may be overdue for cleaning, descaling, or annual maintenance.
- Hot water is not getting as hot as it used to
- Reduced hot water pressure or flow
- Longer wait times for hot water
- Fluctuating water temperature
- Error codes or shutdowns
- Popping, rumbling, or unusual noises
- It has been more than 12 months since the last flush
- The inlet filter shows mineral buildup
Service Area
Based in Woodbury, Serving Irvine First.
Ultra Home Repair primarily provides tankless water heater flush service throughout Irvine, including Woodbury, Stonegate, Great Park, Portola Springs, Orchard Hills, Cypress Village, Northwood, Eastwood, and Beacon Park, plus nearby South Orange County communities.
Diagnosis & Repair
Rinnai Error Code Help in Irvine
A tankless error code does not always mean the unit needs replacement—or that a flush is automatically the answer. Dustin diagnoses and repairs Rinnai tankless systems, including current service focus on Code 11, Code 15, and Code 17.
Rinnai Code 15
Rinnai identifies Code 15 as a Venturi control fault. See an original Irvine repair in which Dustin restored the movement of a sticking Venturi control disc and avoided replacing the complete assembly.
Code 15 Venturi RepairRinnai Code 17
On applicable Rinnai SENSEI models, Code 17 commonly means debris is blocking the venturi. Service can include removing and cleaning the venturi assembly, reinstalling it, and completing the applicable reset procedure.
Code 17 Diagnosis & RepairNo Hot Water or Shutdowns
A unit that will not ignite, repeatedly shuts down, or displays an error code needs diagnosis before anyone assumes flushing is the answer.
Tankless Diagnosis & Repair in IrvineWater Is Not Hot Enough
Lukewarm water, changing temperatures, or lower delivery can point to scale, flow, settings, fixtures, or a repair issue.
Tankless Not-Hot-Enough GuideCommon Questions
Tankless Flush FAQs
How much does a tankless water heater flush cost in Irvine?
Ultra Home Repair offers standard tankless water heater flush service in Irvine for $150 for most standard units. Save $25 ($125 total) when service is completed by October 31, 2026. Existing scope and exclusions apply.
Do you service Rinnai, Navien, Noritz, and Rheem tankless water heaters?
Yes. Standard flush service is available for most common residential tankless water heater brands, including Rinnai, Navien, Noritz, Rheem, and similar units.
Are you based in Irvine?
Yes. Ultra Home Repair is based in Woodbury and primarily serves Irvine homeowners.
What is not included in the $150 flush?
Repairs, diagnostics, replacement parts, stuck valves, missing service valves, unusual access issues, or non-standard system problems are quoted separately.
How do I know if my tankless needs flushing?
Common signs include lukewarm water that used to be hot, longer wait times at the tap, unusual noises, reduced flow, or visible mineral buildup around the unit's valves. Error codes and complete loss of hot water should be diagnosed because a flush is not the correct repair for every fault.
How often should I flush my tankless water heater?
About once a year is a common starting point, but the correct interval depends on the manufacturer, model, water hardness, water treatment, and household usage. Follow the unit's manual and shorten the interval when its guidance or water conditions call for it.
My unit is only a year or two old — do I really need this?
Possibly. Maintenance needs begin with the manufacturer's instructions and local water conditions rather than the age of the unit alone. Irvine Ranch Water District says hardness varies by source, location, and season, so review the manual and service history instead of assuming a newer unit needs no maintenance.
What does the $150 flush include?
The standard $150 service ($125 with the October offer for service completed by October 31, 2026) includes a pre-flush visual check, heat-exchanger descaling using the appropriate medium and procedure for the unit, cold-water inlet-filter cleaning when accessible, a clean-water rinse, restart verification, and an emailed service receipt. Repairs, diagnosis, parts, missing or stuck service valves, and unusual access are separate.
How long does a flush take?
About 1 to 1.5 hours for a standard accessible unit. Circulation and rinse time follow the applicable manufacturer and product instructions.
Can I flush my tankless myself?
Ultra Home Repair's standard professional flush is $150, or $125 with the October offer for service completed by October 31, 2026. It may be more practical than buying equipment for a DIY service. If you choose to do it yourself, follow your manufacturer's instructions carefully to avoid damaging the unit or affecting warranty coverage.
Do I still need to flush my tankless water heater if I have a water softener?
A properly operating water softener can reduce scale, but it does not automatically eliminate the manufacturer's maintenance requirements. The appropriate interval depends on the unit, actual water hardness, household usage, and whether the softener has operated continuously.
What brands do you service?
Rinnai, Navien, Noritz, Rheem, Takagi, and most other tankless brands. If you're not sure what you have, text me a photo of the unit's data plate and I'll confirm.
Do you service my neighborhood?
I primarily provide tankless water heater flush, cleaning, and descaling services in Irvine and Lake Forest. If you are nearby and unsure whether you are in my service area, text me your address and I'll let you know.
What warranty do you offer on the work?
90-day workmanship warranty. If something I touched isn't working right, I come back and make it right.
Why hire you instead of a plumbing company?
Ultra Home Repair is locally owned and operated. Contact Dustin to discuss your unit, the maintenance scope and any separate repair needs. The standard flush is $150; save $25 ($125 total) for service completed by October 31, 2026. Existing scope and exclusions apply, with service documentation provided.
What if my tankless isn't working at all?
A unit with no hot water or an error code should be diagnosed before assuming a flush will fix it. Descaling may help when water-side scale is contributing to the problem, but it will not correct unrelated ignition, venting, combustion, sensor, control-board, or component faults.
Do I need to be home during the service?
Ideally, yes — so you can watch the process firsthand. If you can't be home, I can work with a key or gate code arrangement and send service documentation when the work is complete.
Tankless Flush Reviews
Homeowners Who've Had It Done
★★★★★ 5 stars on Google, plus verified Nextdoor recommendations. These tankless-specific reviews link to their source.
★★★★★
Dustin immediately responded to my call yesterday about a Error code 15 on our Rennai tankless water heater. He was as our place within hours and quickly diagnosed and fixed our problem, and also improved our hot water delivery to our faucets. He is extremely competent, responsive, super communicative and very cost effective! Five stars all around!
★★★★★
I had my tankless water heater flushed at my Irvine condo. Dustin was recommended to us by our HOA so needless to say, he’s very experienced. The service didn’t disappoint. Dustin was efficient and professional, answered all my questions, looked at my water pressure issue and suggested fixes. Highly recommend.
★★★★★
Dustin Swad came by and gave my tankless water heater a long needed flush. He was easy to schedule, was prompt on arrival, and the job was done cleanly and sufficiently. He takes all forms of payment; bill sent via email with payment button. Wouldn’t hesitate to hire him.
★★★★★
Dustin came over to flush our tankless water heater in Northwood Irvine. He was right on time, friendly, and professional. We will definitely have him back again for other work.
★★★★★
Dustin is a great handyman asset that we continue to call upon! He is punctual, cordial, knowledgeable and, most of all, meticulous in his work. Just had him fix an under counter sink that had sank! Before that, replaced LED can lights and even cleaned out and demineralized our tankless water heater.Small or large projects -- you will be glad you called on Justin Swad!
★★★★★
Dusting was great! He came to clean out my tankless water heater. Came on time, fast and also so so nice. Definitely will be using him again for other things now too. Highly recommend
★★★★★
I met Dustin through a friend of mine when I was looking for someone to service my tankless water heater. I called him and he came out within a few days and did an excellent job and was very reasonable compared to the other quotes that I had gotten. Since then I have used him several times for various small jobs around the house. Lastnight he came out after hours and replaced my garbage disposal. Dustin is very thorough, very professional, and most of all He’s very reasonable. I have referred him to many of my friends here in Lake Forest and they are very happy with the work that he has done. I Highly recommend Dustin.
★★★★★
Dustin, owner of Ultra Home Repair, came over to my house at the Great Park in Irvine on a Saturday morning to flush my tankless water heater. He was on time, very personable, fairly priced, and finished in job in approximately one hour. I feel very comfortable recommending him for a tankless water heater flush and will hire him in the future should I require any handyman jobs around the house.
★★★★★
Dustin did a fantastic job on a tankless water heater flush and did it for a very affordable and reasonable price. I’m going to have him comeback and do it next year and the year after that.
★★★★★
Dustin recently descaled my tank less water heater. He does a very clean and thorough job. I can highly recommend him
Hans in Irvine
★★★★★
Dustin did a great job with our Tankless hot water flush out. I watched him do the procedure and he totally knew exactly what he was doing. It went without a problem and his rate for the job was a very good one. I would recommend him for his construction services.
★★★★★
Dustin Swad of Ultra Home Repair replaced 5 faucets for me, changed out a thermostat, and flushed our tankless water heater. He did a great job, was professional, gave me a great price, and I will definitely hire him again in the future!
★★★★★
Dustin was prompt, friendly, helpful, answered all my questions and even researched stuff for me. He serviced the tankless water heater and was great!
★★★★★
We had Dustin come to our house & gave our tankless water heater a check up & flushed the system. We kept his information to have him come back when it's needed again. Very reasonably priced too !
★★★★★
My tankless stopped working last night around 10. I texted Dustin and was pleasantly surprised when he responded within an hour. He came over this morning around 10, flushed the tankless and, as I turned on the hot water while holding my breath, the tankless came back to life. It still amazes me that I got the hot water back in just over 12 hours. Dustin did a professional job and I am truly grateful. Happy to have a great handyman in the neighborhood. Highly recommended.
Ready to Flush Your Tankless System?
Text or call to book. Standard flush: $150. October promotion: $125 when service is completed by October 31, 2026.
What Clients Say
More Happy Customers
★★★★★ 5 stars on Google, plus verified Nextdoor recommendations from Orange County clients.