Signs you need this
- Rusty or rotten-egg smelling hot water
- Rumbling or popping from the tank
- Water around the base pan
- Showers going lukewarm halfway through
Kit on the van, and the method
- Combustion analyser and manometer for gas units
- Multimeter for elements and thermostats
- Drain hose and flush pump
- T&P valve, dielectric unions, venting parts
Before we leave: Fire the unit, check gas pressure or element draw, and time a full-temperature tap.
Common faults by symptom
| What you notice | On a gas heater | On an electric heater |
|---|---|---|
| No hot water | Pilot gone out, dead thermocouple or sensor, faulty gas valve | Tripped high-limit, burned element, tripped breaker |
| Runs out fast | Sediment layer, broken dip tube | Lower element failed |
| Rumbling or popping | Sediment boiling under the water | Scale on the elements |
| Rotten egg smell | Anode reacting with sulphur bacteria in the water | |
| Relief valve dripping | High temperature or pressure, or a tired valve | |
How we test
On a gas tank we check the flue draft first, because a blocked vent is a safety concern before it is a hot water concern. Then we look at the pilot, the thermocouple or sensor, and the burner. Many newer Ontario tanks are power-vented, with a blower on top, so the blower and its pressure switch are part of the check. On an electric tank we isolate power, meter every element and check each thermostat switches, and inspect the wiring for heat damage.
Repairs that make sense
- Thermocouples, sensors, igniters, elements and thermostats are affordable and quick.
- Replacing a dripping temperature and pressure relief valve is routine.
- An anode rod swap can restore a tank that smells, if the tank itself is sound.
- Flushing sediment helps a tank that rumbles, if it has not been left too long.
When repair stops being worth it
A tank leaking from the body, not a fitting, cannot be repaired. Rust coming through the bottom seam is the same story. Age is a factor too: many conventional tanks run somewhere around a decade, and pouring parts into one near that mark is usually poor value. You see the repair figure beside the replacement figure and decide. See our gas water heater replacement page or the field note on water heater lifespan.
Asked on the phone
What temperature should my tank be set to?
Settings around 49 to 60 degrees C are common. Higher settings control bacteria in the tank but raise scald risk, so a mixing valve at the outlet is sensible in homes with children or older adults.