When a tankless water heater in Deer Lake quits without warning, here's what a licensed gas fitter checks before recommending a repair or a replacement.
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Quick answer
A tankless water heater in Deer Lake that suddenly stops delivering hot water is most often signalling a blocked or iced vent, a gas supply or pressure issue, a clogged intake filter, or a failed ignition or flow sensor rather than a full unit failure. If you smell gas or hear the unit repeatedly attempting and failing to ignite, shut it off, leave the home if the smell persists, and have a Technical Safety BC licensed gas fitter read the fault history before any parts are ordered.
Need a licensed gas fitter for your tankless water heater? Call CANRO at (604) 359-1081 — residential natural-gas heating and hot water across Metro Vancouver since 1999.
The Deer Lake area in central Burnaby is one of the city's more established, larger-lot neighbourhoods, with mature tree canopy around Deer Lake Park and homes spanning several building eras from mid-century to more recent executive rebuilds. That mature canopy is a genuine local factor: exterior vent terminations mounted low on a wall collect a steady drop of leaves, seed pods, and conifer needles through fall, more than a newer subdivision with young landscaping would see.
A partially blocked vent from seasonal debris is one of the more common causes of a sudden hot-water outage in this neighbourhood, and it often shows up right after the first heavy leaf-drop or windstorm of the season. In the larger, older executive homes, the second pattern is a tankless unit that was added years after the original build to replace a tank, sometimes on a gas line that wasn't fully re-evaluated for the new appliance's demand.
On a Deer Lake property, we check the exterior vent for seasonal debris first, since it's such a common and easily confirmed cause here, particularly in fall and after storms. We pull the fault history to see whether the pattern matches a gradually worsening blockage rather than a sudden hardware failure.
If the unit was added as a retrofit replacing an old tank, we also test gas pressure and review the branch line sizing against the tankless unit's actual demand. From there we check the igniter, flame sensor, and heat exchanger for wear.
Seasonal debris and retrofit history both shape what we find on a Deer Lake call. We weigh the same core signals on any repair-or-replace decision:
| Signal | Usually points to repair | Usually points to replacement |
|---|---|---|
| Age of the unit | Under roughly 8 years, first major fault | Past 12-15 years or several prior repairs |
| Fault pattern | One isolated fault: a sensor, igniter, or blocked vent | The same fault keeps coming back season after season |
| Heat exchanger | Clean on inspection, no scale or pitting visible | Scaled, corroded, or showing a leak at the exchanger |
| Parts | Common part, normal lead time | Discontinued control board or a long backorder |
| Household plans | You're staying put and the unit is otherwise sound | You're adding a bathroom or suite that will raise demand |
The City of Burnaby requires a permit for tankless water heater installation or replacement. On larger, mature-treed lots, we also check whether the current vent termination location still makes sense or whether a slightly relocated termination would reduce future debris exposure.
If your unit was retrofitted to replace an older tank, it's worth confirming the gas line sizing was properly assessed at the time, since that step is sometimes skipped on a straightforward tank-to-tankless swap.
Safety note
If you're in Deer Lake and smell gas near the water heater, or the unit is repeatedly trying and failing to ignite, treat it as a safety call rather than a repair call: get everyone out of the house, do not flip switches or operate the gas shutoff near a suspected leak, and call FortisBC's emergency line at 1-800-663-9911 from outside. Any work on the gas train, venting, or combustion chamber should be done by a Technical Safety BC licensed gas fitter; CANRO holds gas licence LGA0043870.
A vent termination gradually blocked by falling leaves and needles from mature trees is a very common seasonal cause here; it usually shows up right after the first big leaf-drop or windstorm.
Sometimes, depending on the wall layout and current clearance rules; it's a reasonable thing to ask about if debris blockage keeps recurring.
It's worth checking. If the gas line wasn't reassessed for the tankless unit's demand at the time of the swap, marginal pressure can cause intermittent faults.
Yes, the City of Burnaby requires a permit, and the gas connection must be completed by a licensed gas fitter.
At minimum before winter and after any major windstorm, given how much debris mature trees can drop onto a low exterior termination.
Look at the exterior vent for leaves or needles, confirm the gas shutoff is open, and note when the unit was last serviced or replaced.
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