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Commercial · Commercial Boiler Service & RepairCommercial Boiler Service & Repair
Commercial boiler service and repair comes down to one annual visit done properly and two thresholds that decide the paperwork. The visit covers combustion analysis, the low-water cut-off, the relief valve, expansion tank charge, circulators and water or glycol chemistry. The thresholds: a G2 gas technician may work on appliances up to 400,000 BTU/h and anything larger needs a G1, and low-pressure boilers larger than 30 square feet of wetted heating surface and 30 kW need a TSSA Certificate of Inspection.
Start with who is allowed to touch the burner. In Ontario a G2 gas technician is licensed for appliances up to 400,000 BTU/h input, and a boiler above that needs a G1; the input rating is printed on the boiler's nameplate. Many small commercial buildings — plazas, low-rise apartment buildings, churches, clinics — heat with one or more boilers under that line, often staged so no single appliance is large. Read us the nameplate input when you call, and we will confirm before booking whether the boiler is within our licence class or needs a G1 contractor.
The annual service has a defined scope. Combustion analysis with a calibrated analyzer sets oxygen, carbon monoxide and stack temperature; the low-water cut-off is tested by proving it shuts the burner down; the relief valve is checked against the boiler's pressure rating; and the expansion tank's air charge is measured with the system side isolated. Circulators are checked for noise, leaks and amp draw. On condensing boilers the condensate trap is cleaned and the neutralizer media replaced, because acidic condensate eats cast iron drains and concrete.
Water quality is the part most often skipped. A closed heating loop should lose almost no water, so a system that needs regular topping up has a leak, and every litre of fresh make-up water brings in oxygen and hardness that corrode and scale the boiler. Loops serving make-up air coils, ramps or snow-melt carry glycol, which needs its concentration and inhibitor level tested yearly; tired glycol turns acidic and attacks the system it was meant to protect. We test the loop, record the readings, and say whether treatment, a top-up or a hydronic system flush is justified.
Larger boilers also fall under Ontario's Boilers and Pressure Vessels regulation, O. Reg. 220/01, administered by TSSA. Low-pressure boilers at or below 30 square feet of wetted heating surface, or 30 kW, are exempt; above that, the owner needs a current Certificate of Inspection for each boiler. Periodic inspections for low-pressure boilers run on a two-year cycle and are done by your insurer's inspector where you carry boiler and machinery coverage, or by TSSA where you do not. That inspection looks at the pressure vessel and its safety devices; it does not replace a gas technician's combustion service, and the reverse is also true.
Keep four things in one binder in the boiler room: the Certificate of Inspection, the insurer's inspection reports, each year's service report with the combustion printout, and the water treatment log. Those are what an inspector, an insurer or a buyer's engineer will ask for. Repairs on smaller hydronic systems are covered under boiler repair, and the other equipment in the building under commercial HVAC. A boiler that is down in heating season is an emergency call; for a planned service, book through the shop.
Equipment we install and service
The older workhorses in apartment buildings, schools and churches. Service is burner and flue-passage cleaning, draft and spill checks, and controls testing. They tolerate rough water better than modern boilers but send more heat up the chimney.
Stainless or aluminum heat exchangers, sealed combustion and plastic venting, often installed in a cascade. They need the fire side of the heat exchanger cleaned, the condensate trap and neutralizer serviced, and clean water; they are far less forgiving of sludge and low pH.
Low-water cut-off, pressure relief valve, high-limit and operating controls, flow switch and flame safeguard. Each one is tested, not looked at, and a relief valve that weeps or a cut-off that fails its test is replaced before the boiler goes back into service.
Circulator pumps, the expansion tank, air separator, zone valves and the fill valve with its backflow preventer. A waterlogged expansion tank is the usual reason a relief valve drips every time the boiler fires.
What goes wrong in these buildings
- The relief valve drips into a bucket and someone empties it every week.
- The boiler locks out overnight and the building is cold by six in the morning.
- The insurer's inspector wrote up deficiencies and gave us a deadline.
- We keep adding water to the system and nobody has found where it goes.
- Half the building overheats while the far wing never gets warm.
- The last contractor never left a combustion report, so I have nothing to show anyone.
How it works
We record input rating, pressure rating, fuel and serial number for each boiler, check the licence class it falls under, and read the last inspection report for open deficiencies.
Burner and heat exchanger cleaning, combustion analysis, safety device tests, expansion tank charge, pump checks and a water or glycol test. Deficiencies from an insurer's report are corrected and documented.
A dated service report with the combustion printout, safety test results, water readings and photos, plus a plain list of what should be budgeted next. It goes in the boiler room binder beside the certificate.
Common questions
What size of commercial boiler does ZK Mechanical service?
It is decided by licence class and the nameplate. Ontario limits a G2 gas technician to appliances up to 400,000 BTU/h input, and larger boilers need a G1. Give us the input rating when you call; we confirm before booking whether your boiler is one we can service, and if it is not, we tell you so directly.
Does my boiler need a TSSA Certificate of Inspection?
Low-pressure boilers at or under 30 square feet of wetted heating surface, or 30 kW, are exempt under O. Reg. 220/01; larger heating boilers generally need one. The certificate is issued by TSSA after an inspection, normally carried out by your insurer's boiler inspector. If you cannot find a certificate for a mid-size or larger boiler, ask your insurer or TSSA.
How often should a commercial boiler be serviced?
Once a year, before the heating season, for the full combustion and safety service. Buildings with steam, older boilers or a history of lockouts benefit from a mid-season check of the low-water cut-off and water level controls. The insurer's pressure-vessel inspection runs on its own cycle and does not count as the annual service.
Why does the relief valve keep dripping?
Usually the expansion tank. When the tank loses its air charge or its bladder fails, heated water has nowhere to expand, pressure climbs and the relief valve opens a little each cycle. Other causes are a fill valve feeding too much pressure or a valve seat fouled with scale. Never plug or cap a relief valve; fix the cause.
Related
Keep the building running.
One licensed team for installs, maintenance contracts and 2 AM calls.