One of the biggest selling points of a tankless water heater is longevity. Manufacturers like Navien advertise lifespans of 20 years or more — and that's a realistic number. But it comes with a condition that most homeowners overlook: that lifespan assumes proper annual maintenance.
The reality is that most tankless units in Victoria homes are never serviced after installation. They run quietly in the background for years until something goes wrong — and by then, the damage is often preventable scale buildup that has shortened the unit's life, reduced its efficiency, or caused it to throw error codes.
The good news is that tankless maintenance is straightforward. Some tasks are manageable for homeowners, and the rest are a quick annual service call. Here's what's involved and why it matters — especially for Victoria's water conditions. If you'd rather have a professional handle it, our team offers water heater service across Greater Victoria.
Why Tankless Water Heaters Need Maintenance
A tankless water heater works by heating water on demand as it passes through a heat exchanger. That heat exchanger is the heart of the unit — and it's where problems develop if maintenance is neglected. There are four key areas that need regular attention:
- Mineral scale on the heat exchanger — dissolved minerals in Victoria's water accumulate on the heat exchanger over time, reducing efficiency and eventually restricting flow.
- Inlet filter — every tankless unit has a small inline filter on the cold water inlet. It catches sediment and debris before they reach the heat exchanger. If it clogs, flow drops and the unit can't fire properly.
- Venting — gas tankless units vent combustion gases through a dedicated exhaust. Blockages, corrosion, or improper installation can create safety concerns and performance issues.
- Condensate drain — high-efficiency condensing units like the Navien produce acidic condensate that drains through a small line. If that line clogs, the unit shuts down to prevent damage.
None of these issues are dramatic on their own — but left unchecked, they reduce efficiency, trigger error codes, and can shorten the life of a unit that should last two decades.
Annual Descaling
Descaling — also called flushing — is the most important maintenance task for any tankless water heater. It involves circulating a descaling solution (typically white vinegar or a food-grade commercial descaler) through the heat exchanger to dissolve mineral buildup.
While Victoria's municipal water is relatively soft compared to other parts of Canada, it still contains enough dissolved minerals to cause scale accumulation inside the heat exchanger over time. Mineral content can still leave scale in the heat exchanger.
The process takes about 45 minutes to an hour. Your unit should have isolation valves on the hot and cold water lines — these allow you to close off the unit and connect a small circulation pump to flush the solution through the heat exchanger. If your unit wasn't installed with isolation valves, a plumber can add them during your first service.
Skipping descaling doesn't just reduce efficiency — it forces the unit to work harder to heat water through a layer of scale, which strains internal components and can lead to premature failure of the heat exchanger itself.
Inlet Filter Cleaning
The inlet filter is a small screen located on the cold water inlet of the unit. Its job is to catch sediment, debris, and small particles before they enter the heat exchanger. Over time, it collects material and restricts water flow.
Cleaning it is simple: shut off the cold water supply to the unit, remove the filter (usually by unscrewing a small cap on the bottom of the unit), rinse it under a tap, and reinstall it. The whole process takes about five minutes.
How often you clean the filter depends on your water quality. Once a year is a good starting point. If you notice reduced hot water flow or the unit starts cycling on and off unexpectedly, check the inlet filter first — it's the most commonly overlooked cause of tankless performance issues.
Venting Inspection
Gas tankless water heaters vent combustion gases through a dedicated exhaust pipe, typically running through an exterior wall or up through the roof. Proper venting is essential for both safety and performance.
During an annual service, the vent should be inspected for blockages (bird nests, leaves, debris), signs of corrosion, and proper termination. The vent termination point on the exterior of the home should be clear of obstructions and meet code clearance requirements from windows, doors, and air intakes.
Venting issues are not a DIY item. If you suspect a venting problem — unusual smells near the unit, condensation where there shouldn't be, or error codes related to combustion — call a licensed plumber. Gas appliance venting is safety-critical work that must be done by a qualified professional.
Licensed Plumber vs DIY Maintenance
Some tankless maintenance tasks are manageable for homeowners, while others should always be handled by a licensed professional. Here's a practical breakdown:
Homeowner-manageable tasks
Descaling (if isolation valves are installed), inlet filter cleaning, and checking the condensate drain line for blockages.
Always hire a licensed plumber
Anything involving gas connections, venting, internal components, error code diagnosis, or combustion analysis. Gas appliance work in BC requires a licensed gas fitter — this is a safety and code requirement, not a suggestion.
Signs Your Tankless Water Heater Needs Service
Tankless units are generally reliable, but they do communicate when something is wrong. Watch for these warning signs:
- Error codes on the display — every manufacturer uses different codes, but any persistent error code means the unit needs attention. Don't ignore them or simply reset the unit repeatedly.
- Fluctuating water temperature — if your shower goes hot-cold-hot without you changing anything, the unit is struggling to maintain consistent output. This is often a scale or flow issue.
- Reduced hot water flow — if the hot water pressure seems weaker than it used to be, the heat exchanger or inlet filter may be partially blocked.
- Longer time to reach hot water — while some delay is normal with tankless units, a noticeable increase in wait time can indicate scale buildup or a failing component.
If you notice any of these, don't wait — early diagnosis almost always means a simpler and less costly repair. Call us at (778) 265-6446 to request an appointment.
"We got a call from a homeowner in Gordon Head who was ready to replace their Navien tankless unit — it was throwing error codes, hot water flow had dropped, and they assumed the unit had failed. It was only four years old.
When I pulled the inlet filter, it was completely clogged with sediment. Two minutes of cleaning and a quick test — the unit fired up perfectly. No parts needed, no replacement required. That filter had probably never been checked since install day.
It's a good reminder that tankless units are reliable machines, but they're not maintenance-free. A simple annual check can prevent a lot of unnecessary headaches — and a lot of cold showers."
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Whether your tankless unit needs its annual descaling or you're dealing with error codes and temperature issues, our licensed plumbers can help. We service all major brands across Greater Victoria.
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