No hot water

The first question is scope. If every tap runs cold, the heater is not heating: on a gas tank that is usually a pilot or ignition fault, a gas control or thermopile failure, or the control showing a lockout pattern; on an electric tank, a tripped breaker or high-limit or a failed element; on a tankless unit, a diagnostic code or a unit that will not fire. If only one tap is cold, the heater is working and the problem is in the distribution: a single-handle fixture with a crossed or failed cartridge, a shut-off that is closed, or a long run that has gone cold and is slow to clear.

A tankless unit that worked and then stopped usually shows a code on its display. The code is the starting point, never the diagnosis: look it up on this site for its documented meaning, check the obvious supply items the manual lists, and call with the code if it returns.

On an atmospheric gas tank, no hot water usually means no burner, and the chain to check runs from the pilot up: is the pilot lit, is the control set to a temperature rather than PILOT or OFF, and does the burner come on when the thermostat calls? A pilot that will not stay lit points to the thermocouple or thermopile, the pilot assembly, or the gas control; an electronic control that flashes a pattern is reporting its own fault (Bradford White's ICON System codes are documented on this site). A unit that ran out of gas, or was shut off and relit without following the control's lighting procedure, needs a full relight per the manual.

Before any of that: confirm the gas valve at the heater is open, that other gas appliances work, and that no odour is present. If you smell gas, do not touch switches: leave and call FortisBC at 1-800-663-9911 or 911.

An electric tank with no hot water starts at the panel: check the breaker (a tripped breaker is a symptom, not the fix), then the high-limit on the tank, which many units have as a red button that must be reset by hand after finding why it tripped. If the upper element is dead, the tank delivers nothing because the upper element heats the top of the tank first. Element testing is a multimeter job and the tank wiring is live: this is technician work unless you are qualified, and the water heater circuit must be off at the breaker before any cover comes off.

No hot water is a breakdown, not an emergency, unless something else is happening: a gas smell, a carbon-monoxide alarm, a leaking tank, or water near electrical parts. Those get the FortisBC or 911 call first, then CANRO. For the plain breakdown, the diagnostic visit finds the cause: CANRO states its repair visits carry a diagnostic fee credited toward the repair, and no-hot-water calls are prioritized across its Metro Vancouver service area.