Error-code diagnosis
We read the code, then test the part and the conditions behind it rather than guessing.
Water Heaters · Northern Virginia
Error codes, cold showers and lost output, sorted.
Quick answer
LeMaster Plumber repairs and descales tankless water heaters across Northern Virginia. Most tankless problems are scale in the heat exchanger, an ignition or flame fault, a clogged inlet filter, a venting issue or a gas supply that cannot keep up. We read the error code, find the actual cause, and quote the repair upfront. Call (703) 832-9090.
Tankless units tell you what is wrong, sort of. The error code points at a system, not always at the part. A good repair starts with the code, then checks the things that most often cause it: scale, gas supply, venting and the inlet filter. Swapping a circuit board because the code mentions ignition is how people pay for parts they did not need.
We read the code, then test the part and the conditions behind it rather than guessing.
Flushing scale out of the heat exchanger with the unit’s service valves. Hard water makes this a regular job.
Igniters, flame rods and gas valves tested and replaced when they have failed.
Clogged inlet filters, flow sensors, temperature sensors and combustion fans.
If your unit was installed without isolation valves, we can add them so future flushing is simple.
Being clear about the edges of a job is how you avoid a surprise halfway through it:
We pull the error history and ask when it happens, which narrows it fast.
Gas pressure, venting, scale, filter and sensors are checked before any part is changed.
You get the repair price before work starts. If the unit is not worth fixing, we tell you.
We fix it, then run hot water at more than one tap to confirm it holds temperature.
Why LeMaster Plumber
You approve the price before we start — no surprises and no pressure. You’ll always know the cost before any work begins.
Every job is backed by proper training, the right permits, and a workmanship guarantee.
We show up on time, protect your space, and leave the job cleaner than we found it.
We quote every job upfront and you approve the price before any work begins. What we cannot do honestly is put a number on this page without seeing your situation — so here is what actually moves it:
A flush or a filter is a small job. A gas valve, fan or control board is a bigger one.
Parts availability and price vary a lot by brand.
Units without isolation valves take more work to flush the first time.
If the cause is an undersized gas line, the fix is on the supply side, not the unit.
Tankless units burn a lot of gas at full output, so gas pressure and venting are the first things to check when one misbehaves. Improper venting on a combustion appliance is a safety issue, not just a performance one.
Hard water is the main enemy of a tankless heat exchanger. Regular descaling keeps a unit at its rated output, and a water softener can stretch the time between flushes.
Ready to get it sorted? Pick your own appointment time online.
Or call (703) 832-9090 — we answer 24/7.
We cover all of Fairfax County — Fairfax, Centreville, Chantilly, Vienna, Reston, Herndon, Burke, Springfield, McLean, Annandale and every community in between — plus Ashburn, Sterling and South Riding in Loudoun, and neighboring Arlington, Alexandria, Falls Church and Manassas.
Common causes are scale in the heat exchanger, a clogged inlet filter, a flow rate too low to trigger the burner, or a gas supply that cannot keep up. We test each one.
It depends on your water hardness and use. With the hard water common around Northern Virginia, many homes need it about once a year.
Usually, yes. Tankless units are built to last a long time, and most faults are one part or a flush. A cracked heat exchanger on an older unit is the main exception.
We service the common gas tankless brands. Some warranty repairs have to go through the manufacturer, and we will tell you if that applies.
Codes differ by brand. Tell us the code when you call and we can often tell you what we will be checking before we arrive.
Get In Touch
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