Tankless Water Heater Repair, Flushing and Installation in Broomfield: Is the Switch From a Tank Worth It?
A tankless water heater heats water as it flows, so it never runs out the way a tank can, but it asks more of your gas line, vent and water quality. This page covers the three situations people call about: a unit that has stopped working, a unit that needs flushing, and the question of whether to install one at all. Call our dispatch line and tell the dispatcher which of the three it is.
Call about a tankless unitTankless unit question?
(303) 567-7524Name the symptom or the project, and a plumber who services tankless units takes your address.
- Read any error code on the display.
- Know the unit’s age and fuel type.
- Note whether it was ever flushed.
A tankless heater that stopped working: symptoms, troubleshooting and likely causes
Most tankless units display an error code. The code, plus what the water was doing before it failed, usually points to a short list of causes.
| What happens | Likely cause | First check |
|---|---|---|
| No hot water and an ignition error | No gas flow, a flame sensor or an igniter issue | Is the gas valve open and the gas supply on? |
| Water turns lukewarm after a few seconds | A scaled heat exchanger or a flow sensor problem | When was it last flushed? |
| Hot water that swings hot and cold | Low flow, a partly closed valve or a recirculation setup issue | Does it happen at one fixture or all? |
| A vent or exhaust error | A blocked or disconnected vent, or a condensate drain that is clogged | Look for a visible vent separation and listen for water in the drain |
| The unit will not start at low flow | Flow below the minimum the unit needs to fire | Is a faucet aerator clogged? |
| Leak at the base | A fitting, an isolation valve or the condensate line | Dry the area and find the wettest point |
With any gas smell, get outside, dial 911, then ring Xcel Energy on 800-895-2999. Everything else on this page can wait.
Flushing and descaling a tankless heater with moderate hardness
Minerals in the water deposit inside the heat exchanger as it heats, and a tankless unit has less tolerance for that than a tank. Broomfield’s 2025 report lists hardness running from 25 to 130 parts per million, near 1.5 to 7.3 gpg. That is soft to moderate, so scale builds slowly but it does build, and where the city’s two supplies mix it can vary by address.
- Isolate the unit. Close the isolation valves on the hot and cold lines and the gas valve.
- Connect a pump and hoses. A small pump circulates a descaling solution through the heat exchanger.
- Circulate for the recommended time. The manufacturer’s instructions set the solution and the duration.
- Flush with clean water. Rinse the unit and the hoses before restoring service.
- Clean the inlet filter. A clogged screen reduces flow and mimics a failed unit.
Many makers suggest flushing about once a year as a starting point. A softener changes that; softener and filtration options are set out separately.
Tankless unit acting up or overdue for service?
Say what the display shows and how long since it was flushed. A plumber who services these units takes the job from there.
Tankless or another tank? How the two compare for a Broomfield home
A tankless unit suits a household that wants continuous hot water and has the gas and vent capacity. A tank suits a house where the gas line is small or the budget is tight. Neither is better in the abstract.
| Question | Tankless | Tank |
|---|---|---|
| Runs out of hot water? | Not in a long shower, but flow is capped when several fixtures run | Yes, once the stored volume is used |
| Space | Wall mounted, saves floor area | Needs a floor footprint and a pan |
| Gas and vent | Often needs a larger gas line and its own vent | Usually uses what is in place |
| Maintenance | Needs descale flushing | Needs occasional flushing and an anode check |
| Lifespan | Often longer when maintained | Shorter, and fails by leaking |
| Permit in Broomfield | Required; tank to tankless needs a gas pipe plan | Required for every water heater |
Moving from a tank to tankless is the biggest change. Ask the plumber whether the gas pipe can carry the unit’s load or needs to be replaced, and what the vent will look like.
Installing a tankless unit: gas, vent, permit and the gas pipe plan
The Building Division treats every water heater in Broomfield as permit work, and a switch from tank to tankless adds a gas pipe plan. The plan shows pipe size and length so the city can see the line carries the load. Ask your plumber who prepares and submits it.
Plan for four items on a conversion: a gas line sized for the unit’s input, a vent that is sealed and terminated correctly, a condensate drain if the model is condensing, and a power outlet for the controls. Xcel Energy owns piping to the meter and you own it from the meter on, so changes belong to a licensed plumbing or heating contractor; see gas line work for how that is handled.
Installers differ in which models they carry and service. Ask which brands they install and keep parts for; the one they can repair next year matters more than the one on the box.
Replacing or converting an older unit
A tankless unit that is ten or more years old and keeps throwing the same error may be better replaced than repaired, especially if the heat exchanger is scaled. Replacement with the same model is simple. Converting from a tankless unit back to a tank is also possible and sometimes chosen when the gas supply is the limit.
For the tank side of the decision, replacing a tank heater sets out sizing and the permit steps.
Tankless water heater questions
Should I choose a gas or an electric tankless water heater?
Gas models move more water at a given temperature rise and suit larger households. Electric models are simpler to vent but need a heavy circuit. Your gas line size and your electrical panel capacity usually decide it.
Can an old tank be replaced by a tankless unit, or the other way round?
Yes, in both directions. A tank to tankless change needs a permit and a gas pipe plan in Broomfield, and a conversion back to a tank mostly involves the vent and the pan.
Is a tankless water heater better than a tank?
It depends on the home. Tankless gives continuous hot water and saves floor space, and it asks for more from the gas line and the vent. A tank is simpler and usually costs less to install.
How often should a tankless water heater be flushed or descaled?
Many manufacturers suggest about once a year, and sooner where scale is heavy. Broomfield’s water is soft to moderate, so the interval is usually not short, but the unit’s manual sets the schedule.
A tankless unit that has gone cold?
Tell the dispatcher the error code and whether the unit has power and gas. That narrows the visit before anyone arrives.
Call (303) 567-7524