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Commercial · Commercial Water Heater Repair & ReplacementCommercial Water Heater Repair & Replacement
Commercial water heater repair and replacement turns on one question: is the tank itself leaking? A failed igniter, flame sensor, power-vent blower or gas valve is a repair; water coming from the tank body, or a heat exchanger scaled beyond cleaning, is a replacement. For a restaurant the deadline is set by public health, since a food premises cannot operate without hot water, so the first job is always getting some hot water back before the permanent fix is decided.
Four classes of equipment make most of the hot water in the businesses we see. Commercial gas storage tanks run 75 to 100 US gallons with inputs from about 76,000 to 199,000 BTU/h and up; condensing commercial tanks do the same job at higher efficiency through plastic venting. Cascaded tankless racks gang several wall-hung units under one controller, and booster heaters sit beside a dish machine to lift stored hot water to rinse temperature. Each class fails in its own way, and the right repair starts with knowing which one is on the floor.
Ontario's Food Premises Regulation (O. Reg. 493/17) is why a restaurant treats hot water as an emergency. A high-temperature dishwasher has to deliver a sanitizing rinse of at least 82 °C for a minimum of 10 seconds each cycle, and every handwashing station needs hot and cold running water. A public health inspector who finds neither can order the kitchen closed until it is fixed. If the booster is the only thing down, the dish machine is out of compliance even though the taps still run hot.
Replacement is sized by recovery rate — litres per hour at a stated temperature rise — and not by the number on the tank. A 199,000 BTU/h tank at roughly 80 percent efficiency recovers about 700 litres an hour through a 56 °C rise, and that figure, set against your busiest hour of dishwashing, showers or laundry, decides whether the heater keeps up. Lake Ontario supply water arrives coldest in late winter, so the rise is largest when the building is working hardest. Matching the old tank's gallons while ignoring its input is the commonest way a new heater ends up short.
A bigger input or a different vent type changes the installation under CSA B149.1, the gas code. The gas line and meter have to carry the new load along with everything else on the header, and a condensing tank or tankless rack vents as a positive-pressure, condensing appliance in certified plastic pipe, not into the old chimney or B-vent. Condensing equipment also needs a condensate drain and a neutralizer. Those three items — gas capacity, vent route and drain — are where a like-for-like swap becomes a small project, and they belong in the written quote.
Check the sticker before you call anyone: many commercial heaters are rented from Enercare or Reliance, and a rented unit is serviced through the rental company, not an outside contractor. Owning means you choose who repairs the heater and when it is replaced, which is the usual reason a business buys its next one outright. Our water heater service page covers tanks and tankless units generally, and commercial HVAC covers what else is in the mechanical room. To get a failed heater looked at, call or message the shop.
Equipment we install and service
Atmospheric and power-vented tanks from 75 to 100 US gallons. Repairable faults are the igniter or pilot assembly, flame sensor, gas valve, thermostat probe and the power-vent blower with its pressure switch. A leak from the tank shell or flue is not repairable; shut the cold supply and the gas, and plan the swap.
High-efficiency tanks with a submerged heat exchanger and plastic venting. They add failure points a standard tank lacks: a blocked condensate drain, a spent neutralizer, a fouled combustion blower and intake screens plugged by lint or grease. Most lockouts on these are airflow or drainage, not the burner.
Two or more tankless units staged by a common control so the rack matches demand. A scaled heat exchanger is the main failure, showing up as error codes, temperature swings and one unit doing all the work; igniters, flow sensors and inlet screens follow. Routine descaling is covered under commercial water heater maintenance.
A small heater, usually electric, that lifts stored water to the 82 °C rinse a high-temperature dish machine needs. Elements scale and burn out, contactors and high-limit controls fail, and the symptom is a rinse gauge reading low while every other fixture in the kitchen has hot water.
What goes wrong in these buildings
- The dish machine rinse gauge will not reach 82 °C and the health inspector is due this month.
- We run out of hot water halfway through Saturday service and it takes an hour to come back.
- There is water on the floor around the base of the tank and the puddle is growing.
- The blower on top of the heater runs and runs but the burner never lights.
- I do not know if this heater is ours, the landlord's or a rental.
- The quote I got was for a tank the same size, and nobody asked how much hot water we use.
How it works
Leaking tanks get isolated and the gas shut off; heaters that are not leaking get diagnosed on the spot. We record make, model, input, vent type and whether the unit is owned or rented, because each of those changes what happens next.
A part failure is priced in writing and repaired, often on that visit. For a replacement we work out peak-hour demand, check gas line and meter capacity and the vent route, and quote a heater by litres per hour instead of matching the old label.
Swaps are scheduled for closed hours where the building allows, with the old tank drained and hauled away. Commissioning includes a combustion check and outlet temperatures at the furthest tap and at the dish machine, written down for your files and the health inspector.
Common questions
Can a commercial water heater be repaired the same day?
Often, when the fault is an igniter, flame sensor, thermostat or a common power-vent blower, since those are stock parts. Model-specific gas valves, control boards and booster elements may need a supplier order. A leaking tank is never a same-day repair because it is not a repair at all; the realistic goal that day is isolating it and arranging the replacement.
What does a commercial water heater replacement cost?
It is quoted in writing after a site visit, and residential tank prices do not carry over. The drivers are input rating and tank class, whether the venting can be reused, gas line or meter upgrades, a condensate drain for condensing equipment, and access for getting a heavy tank in and out. We itemize those so you can compare quotes line by line.
Should we switch from a tank to a tankless rack?
It suits long, steady demand such as salons, fitness clubs and laundries, and it adds redundancy because one unit can fail while the others carry on. It suits short, heavy dump loads less well, where a storage tank's reserve helps. Tankless racks also need more gas capacity and regular descaling on Halton and Hamilton water, so the answer comes from your peak-hour numbers.
Can you repair a rented Enercare or Reliance commercial heater?
No. A rented heater belongs to the rental company and their contract covers its service, so the call goes to them. What we can do is quote an owned replacement when the contract ends or a buyout makes sense, and handle the gas, venting and removal so the changeover happens in one visit.
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