Boiler Repair & Installation in Toronto

Repairing and replacing boilers in Toronto's radiator houses

Toronto's west-side semis and row houses in Roncesvalles, High Park, Parkdale and the Junction are radiator country: cast-iron radiators, wide iron mains and no ducts. Many of these systems began life as gravity systems with no pump and were later converted with a circulator, which leaves them holding far more water than a modern system. That history shapes both repair and replacement. A circulator that has seized shows up as a hot boiler and cold radiators, and a compact new boiler dropped onto the old piping without the right near-boiler layout will short-cycle against all that water.

Pressure is the first reading we take. A closed hot-water system normally sits at 12–15 psi cold, enough for two storeys; a three-storey house needs more, and a top-floor radiator that is cold and will not bleed is often short of fill pressure, not broken. At the other end, the relief valve opens at 30 psi, and a boiler dripping from that valve on every heating cycle usually has a waterlogged expansion tank, which in older houses is a plain steel cylinder strapped between the basement joists. Recharging it or fitting a diaphragm tank falls in the $150–$800 repair range, and why radiators are cold sorts the other causes by symptom.

Replacement is the right call when the cast-iron sections or the heat exchanger leak, or when a major repair on a boiler past 30 years costs more than half of a new one; should I repair or replace my boiler works through it. The modern choice is a wall-hung condensing boiler, often a combi that also makes domestic hot water, and it vents through plastic pipe, so the narrow lot matters: the termination has to clear windows, doors and the neighbour's openings under CSA B149.1, which often means the rear wall or the roof. Old radiators help here, because they were sized for a leakier house and can heat today's house with cooler water, which is where a condensing boiler earns its efficiency. We give no price before a site visit, since radiator count, venting route and the combi question move it too much; how much a new boiler costs in Ontario gives the ranges.

Two cautions are specific to these houses. The white or grey wrap on old boiler pipes may contain asbestos, so we do not cut or strip it; if pipe has to be opened there, an abatement contractor removes the wrap first. And when a boiler is replaced with a side-vented unit, a gas water heater left alone on the brick chimney needs its venting re-checked. Gas comes from Enbridge, any permit goes through Toronto Building, and the work is done by a TSSA-licensed technician; start with the boiler repair service page, the Toronto service area page, or book a boiler visit.

Why ZK Mechanical for boiler repair & installation in Toronto

• Technicians who work on hot-water heat: circulators, zone valves, aquastats, expansion tanks and relief valves
• Fill pressure set for the height of the house, so third-floor radiators get water
• Converted gravity systems recognized and piped correctly when a new boiler goes in
• Vent terminations planned around neighbouring windows before a condensing boiler is quoted
• Suspected asbestos pipe wrap left undisturbed and flagged, never cut
• Diagnostic $90–$150 and typical repairs $150–$800, priced in writing first
• No-heat boiler calls taken on the 24/7 line with no after-hours surcharge

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