Water Heater Maintenance Schedule for Gas Tanks and Tankless Units

Bradford White's installation and operation manual sets out the homeowner and technician maintenance for its Defender storage tanks: the anode rod is inspected on a two-year interval, the temperature-and-pressure relief valve is operated annually, sediment is drained from the tank periodically, and the unit is checked by a technician each year. Rinnai's manual for its condensing tankless series calls for flushing the heat exchanger at least annually and states that failure to flush can damage it.

Those intervals are manufacturer requirements, not suggestions. On a tank, skipping the anode lets the steel tank become the sacrificial part. On a tankless unit, skipping the flush lets scale and debris accumulate in a heat exchanger that is expensive to replace.

A storage tank protects itself with a sacrificial anode rod that corrodes in place of the steel. Metro Vancouver reports treated-water hardness of roughly 2 to 25 mg/L as calcium carbonate depending on the source, which is very soft water: scale builds slowly, so the anode and the tank lining carry more of the wear. A partially consumed anode can be replaced, which is far cheaper than a tank that has begun to leak from the inside.

The relief valve is a safety device, not a maintenance item for a homeowner to operate. Its annual exercise and any replacement belong to a licensed technician, who can also confirm the expansion control and the discharge pipe are correct. The same rule applies to the gas control, the burner and the venting: those are inspected, never adjusted by an unlicensed person.

A condensing tankless unit should be descaled at least once a year. The service pumps a manufacturer-approved solution through the heat exchanger using the isolation valves, cleans the cold-inlet screen, checks the condensate trap and neutralizer, verifies combustion and venting, and resets the service reminder. Units installed without isolation valves get them fitted first so the annual job stays quick.

Soft water makes the year gentler, not optional. Rinnai's manual ties the flush to the warranty, and a unit that runs year-round through a wide winter temperature rise is working hardest in the season a neglected heat exchanger shows it.

A maintenance visit follows the schedule for the installed equipment: on a tank, the anode, the relief valve, the drain and the venting; on a tankless unit, the flush, the inlet filter, the condensate path and the combustion check. The technician records what was found and what was done, which is the maintenance history a warranty claim may ask for.

Maintenance that only inspects, tests and cleans does not change the gas system, so it does not attract a gas permit. Anything the visit turns up that becomes permitted work, such as a failed relief valve or a corroded flue, is flagged and priced before it is done.

Gas lines, the gas control, the burner, combustion air, venting and anything electrical are licensed-technician work. This site publishes no do-it-yourself instructions for those systems, and it does not suggest bypassing a safety device. If a relief valve is discharging, a burner will not light, or a tankless unit is locked out, the safe step is to stop and call rather than to keep resetting.

For a gas smell or a carbon-monoxide alarm, leave the building and call the FortisBC emergency line at 1-800-663-9911 or 911 first.

CANRO Heating & Cooling offers water-heater maintenance, tank flushing and tankless descaling across its verified Metro Vancouver service area, following the manufacturer's schedule for the installed equipment. The visit ends with a written note and recommendations, with no pressure to replace equipment that is working.

Pricing for a maintenance visit is confirmed by phone; this site does not publish amounts it has not verified. Repair visits carry a diagnostic fee that CANRO states is credited toward the repair if you proceed, while replacement and installation estimates are free.