First 60 Seconds: Quick Checks
A tankless water heater with no hot water is often recoverable in under a minute. Run through these basics before assuming the worst.
Power: Confirm the unit has power. Check that the wall switch is on and the breaker has not tripped. Many tankless units need electricity to fire even though they burn gas.
Gas: Make sure the gas is on. If other gas appliances (stove, furnace, fireplace) are also out, the issue is the gas supply, not the heater. Check that the gas valve at the unit is open.
Water flow: Tankless units need a minimum flow rate to ignite. A barely-open tap or a partially closed isolation valve can prevent firing. Open a hot tap fully and see if the unit kicks on.
Error code: Look at the display or remote controller. A code is a direct clue — write it down exactly as shown.
Common Reasons a Tankless Stops Heating
Tripped breaker or lost power after a surge or storm — common in the Lower Mainland's wetter months.
A fault lockout. After repeated failed ignitions, the unit locks out for safety and shows a code. A single power cycle (off at the breaker for 30 seconds, then on) sometimes clears a one-off fault, but a code that returns immediately means a real problem.
Cold-weather flow or freeze issues. During a cold snap, a frozen condensate line or inlet can stop operation; severe freezing can damage the unit.
Gas supply problems, including a regulator issue or an empty propane tank if you are on propane rather than natural gas.
Scale or ignition component failure. Heavy scale, a failing igniter, flame sensor, or gas valve will stop heating and usually throw a code.
A leak that tripped a safety sensor, which is why no-hot-water and leaks sometimes appear together.
What You Can Try Safely (and What to Avoid)
Safe to try: cycle the power once, fully open a hot tap to confirm adequate flow, verify the gas valve is open, reset a tripped breaker once, and check whether other gas appliances work. If you are on propane, confirm the tank is not empty. Note any error code before and after each attempt.
Do not attempt: opening the sealed cabinet, bypassing safety lockouts, relighting anything if you smell gas, or repeatedly resetting a unit that keeps faulting — repeated forced ignitions can be unsafe. If you smell gas at any point, stop, leave the area, and call your gas utility's emergency line and then a licensed gas fitter. Tankless units combine gas, electricity, and water, so anything past the basic external checks belongs with a professional.
When to Call for Emergency Service
Call without delay if you smell gas, if the unit faults repeatedly with the same code, if there is no hot water in cold weather, or if no-hot-water comes alongside a visible leak. A total loss of hot water in winter is genuinely disruptive, and a licensed technician can usually diagnose it quickly.
Tankless water heaters are serviced by our parent company, CanroHeat, with the parts and Red Seal credentials these units require. Whether it is a locked-out ignition, a failed flame sensor, a frozen line, or a gas-supply fault, we will get to the cause fast and restore your hot water. Call CanroHeat at 604-359-1081 for emergency tankless no-hot-water service across Greater Vancouver — have your model number and any error code ready and we will move quickly.