Water Heater Questions, Answered

Buy.

A conventional tank water heater in Ontario lasts 8 to 12 years; a tankless unit lasts 15 to 20.

On a gas tank, no hot water is usually a pilot that has gone out, a failed thermocouple ($150–$300 to replace) or a gas control valve ($400–$600).

Size a tankless water heater by flow at a GTA winter temperature rise.

Replacing a tank water heater in Ontario costs $1,200–$2,500 installed; a tankless conversion runs $3,500–$6,500, with the most common 199,000 BTU gas swap landing at $4,200–$5,000.

A tankless water heater is worth it in Ontario if you will stay in the home 10+ years, run out of hot water with your tank, or want the floor space back: it lasts 15–20 years against 8–12 for a tank and saves $80–$200 a year in energy.

A water heater pilot light that keeps going out is usually a worn thermocouple or thermopile that can no longer hold the gas valve open, a clogged flame-arrestor screen starving the burner of air, or a draft pulling the flame off the pilot.

A water heater that pops, rumbles or crackles almost always has a layer of mineral sediment on the tank bottom; water trapped under it flashes to steam and bangs its way out.

Where the water shows up tells you why your water heater is leaking.

To relight a water heater pilot light, turn the gas control knob to Off and wait five minutes for any gas to clear.

An anode rod replacement is one of the cheaper water heater jobs: the rod itself is an inexpensive part, and the visit lands at the low end of the $150–$800 range for tank repairs, with the $90–$150 diagnostic folded in.

A like-for-like tank water heater replacement takes two to four hours, and you have hot water again the same afternoon.

Set a tank water heater to 60°C at the tank and deliver no more than 49°C at the taps through a mixing valve.

Hot water that runs out fast on a tank that used to keep up points to a cracked dip tube sending cold water straight to the hot outlet, a bed of sediment displacing capacity, or a dead lower element on an electric tank.

Hot water that smells like rotten eggs almost always means hydrogen sulphide gas is forming inside the tank: harmless sulphate-reducing bacteria in the water feed on the magnesium anode rod and release the gas.

Yes — a properly sized gas tankless water heater can run a whole house, including two showers at once, in a typical Burlington or Oakville home.

A tankless water heater that goes hot, then cold, then hot again is usually a 'cold water sandwich': turn a tap off and back on within minutes and you get the hot water left in the pipe, then the cold slug that went through the unit as it re-ignited.

Usually, yes.

An electric water heater that trips the breaker most often has a heating element whose metal sheath has cracked, letting water reach the live wire and short it to the tank.

A heat pump water heater is worth it in Ontario when it replaces an electric tank: in heat pump mode it uses about a third of the electricity for the same hot water, and on Ontario's ultra-low overnight rate it can heat when power is cheapest.

A water heater taking longer than it used to heat up usually has sediment insulating the burner or burying the lower element, a broken dip tube mixing cold water in near the top, or a thermostat set too low.

You need an expansion tank if your home has a closed plumbing system — a check valve, backflow preventer or pressure-reducing valve on the water service that stops heated, expanding water from pushing back into the municipal main.

To turn off a leaking water heater, close the cold-water valve on the pipe above the tank, then cut the energy: turn the gas control knob to OFF and close the gas shut-off, or switch off the double-pole breaker on an electric tank, or unplug a power-vent model.

To reset an electric water heater, switch off its breaker, remove the upper access panel and press the red ECO button on the upper thermostat until it clicks.

A water heater mixing valve is bad when hot water is lukewarm or swings between warm and hot at every tap, when it suddenly runs scalding, or when hot flow drops while cold stays strong.

A water heater relief valve drips for one of three reasons.

The blinking light on a gas water heater is the status code from the gas control.

An electric water heater that is not heating has usually lost power or lost an element.

A tankless water heater shuts off mid-shower for one of two reasons.

A tankless water heater that is not igniting is missing gas, spark or air.

A power vent water heater that runs but does not ignite usually has a blower that works and a pressure switch that will not close, because the intake or exhaust is blocked, iced or nested at the sidewall, or the switch tubing is cracked.

If your tankless water heater is frozen, do not try to fire it.

The signs a water heater is about to fail are rusty water from the hot taps only, rumbling or popping as it heats, moisture or rust trails at the base, a relief valve that keeps weeping, and hot water that runs short.

A tankless water heater needs descaling when the hot water temperature swings during a steady draw, hot flow has dropped while cold is normal, the unit rumbles or crackles as it fires, or it shows a scale or overheat code such as Rinnai LC or Navien E016.

A water heater reset button keeps tripping because the water at the top of the tank is passing roughly 77–82 °C, the point where the energy cut-off (ECO) opens.

Hot water that is only lukewarm usually means cold water is mixing in or half the heater has stopped working.

Hot water that is suddenly too hot means the heater has lost control of its temperature or the mixing valve has stopped tempering it.

A water heater pilot that will not light at all is missing spark, gas or air.

A pilot light that is on with no hot water means the main burner is not firing or its heat is not reaching the taps.

Hot water pressure that is low while cold is fine means a restriction on the hot side only, between the heater's cold inlet and the taps.

A tankless water heater takes longer to deliver hot water than a tank because it adds an ignition delay of several seconds to the time needed to push cold water out of the pipe.

A tankless water heater that is not getting hot enough is usually being asked for more than it can deliver.

Brown or rusty hot water comes from the water heater when only the hot side is discoloured: the anode rod is used up and the steel tank is corroding, which on a tank over about 10 years old usually means replacement.

A tankless water heater makes noise for four main reasons: scale in the heat exchanger (rumbling or kettling), a worn combustion fan (whine or grinding), valve and sensor clicking, or vibration in the vent and water pipes.

A gas tankless water heater needs 120-volt power for its control board, fan and igniter, so it stops in an outage and sometimes stays off afterward.

Water heater maintenance in the Greater Toronto and Hamilton Area is priced like any other tune-up visit: $120–$250 for an annual service on a tank, and $150–$300 for a tankless descale flush.

Tankless water heater repair in the GTA typically costs $150–$800, plus a $90–$150 diagnostic visit that is credited toward the repair.

A water heater inspection by a licensed gas technician is a diagnostic visit, so in the GTA it costs $90–$150.

Tankless water heater maintenance costs $150–$300 for an annual descale flush on a unit that has isolation valves.

A water heater maintenance plan is worth it for a tankless unit on hard water, for a power-vent tank, and for a home already on a furnace and AC plan where the water heater is added to the same visit.

To get out of a Reliance water heater rental you either buy the tank where it sits or terminate and return it.

You get out of an Enercare water heater rental by buying out the existing tank or by cancelling and returning it under your agreement.

Buy out a rental water heater that is under about five years old and working well.

Yes, replace a tank water heater before it fails once it is past 10 to 12 years and showing rust, moisture or rumbling, especially beside a finished basement.

A like-for-like water heater replacement in a house usually needs no building permit in Ontario, but the municipality decides: Toronto lists hot water tanks among work that needs none, while Burlington and Mississauga do not name them.

A water heater rental buyout price is calculated by the rental company from the tank's type, size and age on a declining schedule: the older the tank, the lower the figure.

Yes.

You can end the rental, but you should not remove a rental water heater yourself in Ontario.

Check three things: the tank, the bills and your closing documents.

A tankless water heater installation takes about 3 to 4 hours when a new tankless replaces an old one, and 6 to 8 hours, one working day, when a tank is converted to tankless.

Usually in part.

In Ontario you can install your own gas water heater only in a detached house you own and live in, and you may not turn it on until a TSSA-certified gas technician confirms the installation meets the gas regulation.

Your water heater rental fee keeps going up because the rental agreement lets the company raise the rate, usually once a year, for as long as the tank is in your house.

The lease decides.

Bosch tankless error code EA means ignition failure: water is flowing but the control unit did not recognize a burner flame.

Navien error code E003 means ignition failure: the heater called for flame and could not prove one, so it locked out.

Navien error code E004 means false flame detection: the control board sees a flame signal when the burner should be off.

Navien error code E012 means flame loss: the burner lit, then the flame signal dropped out while the heater was running.

Navien error code E016 means the heat exchanger is overheating.

Navien error code E030 means exhaust overheating: an NPE-2 shuts down when flue temperature passes 65 °C (149 °F).

Navien error code E110 means abnormal air pressure: the heater senses a restriction in its exhaust or intake air path.

Navien error code E407 means the hot water outlet thermistor is open or short-circuited: the heater has lost its outlet temperature reading.

Navien error code E515 means abnormal operation of the PCB: the control board has failed a self-check.

Noritz error code 11 means ignition failure: the heater sees a demand for hot water but cannot light, or it lights and the flame rod does not detect flame.

Noritz error code 90 means a combustion abnormality: the mix of fuel and air at the burner is off specification.

Error code 11 on a Rheem tankless water heater means the flame rod does not detect a flame.

Rinnai error code 10 means the air supply or exhaust is blocked; on SENSEI models it also means the condensate trap is full.

Rinnai error code 11 means no ignition: the heater tried to light its burner, no flame was established, and it has locked out.

Rinnai error code 12 means flame failure: the burner lit and the flame was then lost.

Rinnai error code 14 means the thermal fuse or overheat sensor has tripped: the heat exchanger ran hotter than its limit.

Rinnai error code 16 means high outgoing water temperature: a safety shutdown because the outlet water exceeded 95 °C (203 °F).

Rinnai error code 25 means a condensate pump error or a clogged drain: condensate has backed up and tripped the condensate safety (float) switch.

Rinnai error code 79 means water leakage has been detected inside the heater; it applies to Non-SENSEI series models.

Rinnai error code LC means scale build-up in the heat exchanger; it shows as LC or LC0 to LC9, and as 00 in the maintenance history.

2 flashes on a water heater status light means low thermopile voltage on Bradford White and A.

4 flashes on a water heater status light means excessive tank temperature: the high-limit cut-out (ECO) has shut the heater down.

7 flashes on a water heater status light means a gas control electronic fault: the Honeywell control on Bradford White and A.