Tankless water heater maintenance in Houston

What the 12-point service covers.

Most Houston homeowners think a tankless water heater is maintenance-free, whatever the salesperson said. It isn’t.

We don’t show up, run some vinegar through your unit and call it a day. Our 12 checkpoints address every failure we have come across in more than 1,400 Houston tankless systems. Here is what that covers.

A baseline reading first.

Before we touch anything, we measure the flow rate, temperature rise and gas consumption. That gives you a before-and-after comparison of what the service achieved. Most homeowners are surprised by how much performance they had lost without noticing.

Professional descaling.

We connect a commercial-grade circulation pump and run professional descaling solution through the heat exchanger for 45 to 60 minutes, at a consistent flow and pressure. The solution is formulated for tankless heat exchangers, so it dissolves calcium and magnesium deposits without corroding copper, stainless steel or rubber gaskets. We monitor the solution’s pH throughout. When it stops changing, the scale is gone. Rushing this step leaves deposits behind, which defeats the purpose.

Why vinegar won’t cut it.

Some YouTube videos suggest running white vinegar through the unit. We have flushed systems where the homeowner had done exactly that for three years, and the vinegar had barely touched the scale. White vinegar is about 5% acetic acid. It works on light surface deposits, but Houston’s water forms calcium carbonate scale that bonds to the metal at a molecular level. After 12 months baking onto copper fins at 140-plus degrees, household vinegar isn’t strong enough to dissolve it efficiently.

The inline filter.

Every tankless unit has a small mesh filter where the cold water enters, and the sediment in Houston’s water clogs it over time. A restricted filter reduces flow, which causes that annoying hot-cold-hot pattern in the shower. We pull it, clean it thoroughly and inspect it for damage.

The burner assembly.

We remove the burner cover and look for sooting, discoloration and debris. A dirty burner doesn’t ignite cleanly, which wastes gas and can produce carbon monoxide. Houston’s humidity and occasional flooding can bring moisture into burner chambers, so this check matters more here than in drier climates.

Venting and safety.

We inspect the whole vent run, from the unit to where it ends outside. Bird nests, wasp nests and shifted PVC joints are more common than you’d think in Houston, and a blocked or disconnected vent can push carbon monoxide into your home. We don’t take this check lightly.

Gas pressure.

With a manometer, we confirm that the gas pressure at the unit matches the manufacturer’s specification, typically 3.5 to 4.0 inches of water column for natural gas. Too low and the unit underperforms. Too high and you risk damaging the gas valve. Houston’s gas pressure can shift with the seasons, especially in newer subdivisions where the infrastructure is still settling.

Condensate drain and sensors.

Condensing units, increasingly common in Houston installations, produce acidic condensate that drains through a small line. If the line clogs, the unit shuts down with exhaust-temperature error codes. We clear the drain and clean the temperature sensors that control combustion. They drift over time and can make the unit run lean or rich, wasting gas either way.

The Delta T test.

After descaling, we measure the incoming cold water temperature and the outgoing hot water temperature at maximum flow. The difference between the two is your Delta T. In Houston, where incoming water averages about 67°F on Rinnai’s groundwater map and shifts with the seasons, a healthy unit should produce a Delta T of 40 to 60 degrees, depending on the model and the incoming water temperature. Below 35 degrees at normal flow, something is wrong: scale remains, the burner isn’t firing at full capacity or the unit is undersized for the home. We work out which one during the visit.

Before and after, side by side.

Once everything is cleaned, inspected and adjusted, we repeat the baseline test and show you both sets of numbers.

Every brand has its quirks.

Rinnai units from 2018 and earlier have a known issue with flame rod corrosion in humid climates. Navien’s NPN series has a condensate trap design that clogs faster in Houston’s hard water than Navien’s own maintenance schedule accounts for. Noritz units installed with an improper vent slope, which we see constantly, develop condensation pooling that corrodes the heat exchanger from the outside in. When we spot a model-specific issue, we flag it before it becomes a bigger repair.

When to book.

For most Houston homes, once a year is the right cadence. If your water is particularly hard (above 15 grains per gallon) or your household uses more than 80 gallons of hot water a day, twice a year is better, and we can test your water hardness on the first visit. Early fall is the best time to book, before Houston’s brief cold season when the unit works hardest. If it has been two or more years since the last flush, don’t wait for an error code. We’ll get your system back to factory performance before something breaks that didn’t have to. For a tank water heater, our water heater repair service is the place to start.

We serve every corner of Greater Houston, from Katy to Baytown and Sugar Land to The Woodlands. Call 832-673-0909 or contact us for a quick quote over the phone. Most appointments are available within 48 hours, and two-hour arrival windows mean you don’t lose your whole day waiting.