TANKLESS WATER HEATER SERVICE

Tankless Water Heater Repair

A tankless unit that flashes an error code or turns a hot shower cold is not working the way it should. Tankless water heater repair helps residential and commercial customers address ignition trouble, sensor faults, scale buildup, blocked airflow, low hot-water flow, and temperature changes.

Daniel’s Plumbing & Son works on tankless systems that no longer produce steady hot water. The first step is to review symptoms, displayed codes, and conditions affecting water, gas, electricity, venting, and airflow.

If recurring faults make replacement worth considering, review tankless water heater installation. For routine scale and condition checks, see water heater maintenance, or explore our complete plumbing services.

SYSTEM DIAGNOSTICS

What Tankless Water Heater Repair Addresses

A tankless water heater starts heating when it detects water moving through the unit. Sensors, controls, heating parts, water passages, and safety devices must respond correctly for the system to work.

The same symptom can have more than one cause. An error code can narrow the search but should not be treated as a complete diagnosis by itself.

COMMON REPAIR CONCERNS

Problems That May Affect a Tankless System

Repair should follow the condition found rather than assuming every symptom needs the same service.

Mineral Scale

Hard-water minerals can collect along heat-transfer surfaces and narrow water passages.

Restricted Filters or Passages

A clogged inlet filter, valve, supply line, or internal passage may reduce hot-water flow.

Ignition or Flame Failure

Gas supply, ignition controls, flame sensing, airflow, exhaust, electrical, or regulator conditions may be involved.

Sensor or Control Faults

Sensors and controls regulate flow, temperature, flame, and shutdowns and may misread conditions when faulty.

Airflow or Vent Restrictions

Blocked intake, obstructed exhaust, damaged venting, poor airflow, or debris near terminations can trigger shutdowns.

Safety Shutdowns and Error Codes

Repeating codes may relate to flow, temperature, ignition, airflow, or another monitored safety condition.

WARNING SIGNS

Signs Your Tankless Water Heater Needs Repair

A change in temperature, flow, sound, or display behavior is worth paying attention to.

Error Codes on the Display
Write down the exact code before turning the unit off. Do not keep resetting when the same code returns.

Hot Water Turns Cold
Describe whether the temperature change occurs during one use, at low flow, or when another fixture opens.

No Hot Water
Check whether every hot-water fixture is affected or only one location.

Reduced Flow on the Hot Side
If only hot flow is weak, a filter, mineral restriction, valve, unit passage, or hot piping may be involved.

New Clicking, Rumbling, or Screeching
The sound alone does not identify the failed part, but timing and related codes are useful.

POSSIBLE CAUSE GROUPS

What May Interrupt Tankless Operation

Mineral Scale and Water Restrictions

Scale may contribute to reduced flow, longer waits, temperature swings, rumbling, overheating codes, or shutdowns, but filters and valves may also restrict flow.

Ignition, Gas, Airflow, and Venting

Gas systems need stable fuel, ignition, flame sensing, intake, and exhaust. Do not open the unit or adjust gas components as a test. If gas is smelled, leave and follow utility emergency instructions.

Electrical, Sensor, and Control Faults

A blank controller, returning codes, inconsistent temperature, no response to flow, or repeated shutdowns may involve sensors, controls, or electrical power.

THE REPAIR REQUEST

What to Expect When Requesting Repair

Describe the Water Behavior
Explain whether it starts hot then turns cold, remains cold, loses flow, or shuts down.

Record the Display Information
Share the exact code, lights, controller behavior, and whether it returns after a reset.

Identify the Affected Fixtures
Mention whether every hot tap, showers only, or one fixture has the problem.

Review System Conditions
Water flow, buildup, gas, power, ignition, sensors, intake, exhaust, model information, and installation may need consideration.

Confirm Repair or Replacement
The current fault, unit condition, repair history, parts, demand, and installation should be reviewed before replacement is discussed.

BEFORE YOU CALL

Useful Information to Have Ready

Do not remove covers or reach into the unit. The controller, label, and visible exterior may provide enough detail.

Brand and Model

Provide the manufacturer and model from the visible label when it can be read safely.

Exact Error Code

Write down the exact number, light pattern, or controller message.

Gas or Electric

State whether the system is gas or electric and whether any utility interruption is known.

Affected Fixtures

Explain which hot fixtures are affected and whether several fixtures can run together.

Flow, Temperature, and Sounds

Describe reduced flow, cold bursts, settings that do not hold, clicking, rumbling, or screeching.

Recent Work and Maintenance

Mention recent plumbing, gas, or electrical work, the last known maintenance date, and photos of the display and installation area.

REPAIR, REPLACEMENT, OR MAINTENANCE

Choose the Next Step After the Fault Is Identified

Repair may fit a serviceable sensor, filter, valve, control, connection, or replaceable part. Replacement may deserve discussion after major internal damage, repeated failures, unavailable parts, or an impractical repair is confirmed.

Routine maintenance supports normal operation, while repair addresses an active fault. The two may overlap when mineral buildup or a clogged filter contributes, but routine care cannot correct every ignition, sensor, control, or venting failure.

Repeated resets are not a repair when the same fault returns.

TRUST AND PROOF

Licensed Plumbing Work Backed by 30 Years in Business

Inviting a plumber into your home or business takes trust. You need someone who respects the property, gives clear answers, and takes the time to find the source of the problem.

Daniel’s Plumbing & Son brings:

30 years in business
California contractor license #672432
149 total customer reviews
Residential and commercial plumbing experience
Service across multiple communities
Clear communication before and during the job

REVIEWS

What Customers Say About Daniel's Plumbing & Son

    
 
 
         
   Just John 
 
 
 
 Trustindex verifies that the original source of the review is Google. So I come back from a trip days ago. I come back to a shower head that rumbles. Submit a maintenance request and then we are given the amazing opportunity to meet Rich and his team member.

I cannot exaggerate this but they literally tackle it within minutes. All while being very kind and respectful which is always appreciated. No more rumbling shower head and less headaches for my family and I. Thank you Rich. Hopefully if we have future problems we get to have you on the Job!!
  
 
        
   Brad 
 
 
 
 Trustindex verifies that the original source of the review is Google. Rich was great - on time, friendly, worked quickly, and did a great job!
  
 
        
   J Outwater 
 
 
 
 Trustindex verifies that the original source of the review is Google. Stand up guys who responded quickly and did a high quality repair.  You can trust them.
  
 
        
   Jerry Simpkins 
 
 
 
 Trustindex verifies that the original source of the review is Google. Happy with service very professional, quick, and efficient cleaned up after work was completed.
  
 
        
   Dr. “DrDownstrum” Downstrum 
 
 
 
 Trustindex verifies that the original source of the review is Google. Very professional. Guy arrived, made the job look easy, and left me appreciative. Thank you for the service.
  
 
        
   Nelly G 
 
 
 
 Trustindex verifies that the original source of the review is Google. Prompt friendly service from Rich
  
 
        
   Katie Desmond 
 
 
 
 Trustindex verifies that the original source of the review is Google. A friend referred us to Rich from Daniel’s Plumbing and Son. They came right away and solved all the issues we were having. Communication was clear. We will be calling them the next time we need a job done.
  
 
        
   Dulce Romero 
 
 
 
 Trustindex verifies that the original source of the review is Google. Rich did an awesome job fixing a couple issues at my place, with zero hesitation. Its great seeing someone who knows how to take initiative and knows exactly what hes doing when it comes to his field of work its admirable and hard to come by nowadays! Him and his colleague were in and out and respectful of the house which I really appreciated as well. Great work!
  
 
        
   Solares Cabrera 
 
 
 
 Trustindex verifies that the original source of the review is Google. Rich did a great job. Unclogged both bathtubs and diagnosed and fixed one of the toilets. All of this within the span of half an hour. This expedited service was amazing. I highly recommend giving them a try for your plumbing needs.

How It Works

Getting professional help shouldn’t be complicated. Our 5-step process ensures transparency and quality.

Contact

Call us or fill the form.

Schedule

Book a time that works.

Inspect

Pro on-site evaluation

Review

Get Transparent pricing.

Complete

Job done to perfection.

SERVICE AREAS

Serving Southern California

Daniel's Plumbing & Son — Long Beach, CA

Proudly serving Long Beach, CA and nearby communities including:

Daniel's Plumbing & Son — San Diego, CA

Proudly serving San Diego, CA and nearby communities including:

Daniel's Plumbing & Son — Corona, CA

Proudly serving Corona, CA and nearby communities including:

TANKLESS REPAIR FAQ

Common Questions About Tankless Water Heater Repair

Why does my tankless water heater show an error code?

The code may relate to ignition, flame detection, airflow, venting, flow, temperature, or another monitored condition. Meaning depends on the model.

Why does my shower turn cold and then hot again?

Changing flow, a sensor, bypass, or demand from another fixture may be involved.

Can mineral buildup stop a tankless unit from working?

Heavy buildup may restrict flow, affect heat transfer, and contribute to overheating or shutdown codes.

Why is hot-water pressure lower than cold-water pressure?

A restriction in the unit, inlet filter, valve, or hot-water piping may reduce flow.

Should I keep resetting the unit?

One reset may restore a temporary fault. If the same error returns, repeated resets are not a repair.

Does no hot water mean the unit must be replaced?

No. Ignition, sensors, controls, flow, venting, power, or fuel supply may cause shutdown.

What should I mention when calling?

Provide the code, brand, model, fuel type, affected fixtures, temperature and flow changes, sounds, and recent work.

RESTORE STEADY HOT WATER

Get the Tankless System Working Properly Again

Cold bursts, low hot-water flow, and repeating error codes are easier to address when the exact symptoms are clear. Call Daniel’s Plumbing & Son with the unit model, display code, and a simple description of what happens when hot water is used.

You do not need to open the unit or keep resetting it first. Bring the details you can see and hear so the team can determine the next step for tankless repair.