A lot of the older housing stock in Cabbagetown, the western Distillery fringe, and pockets of Corktown still runs on hot water — either a cast-iron sectional boiler feeding rads, a wall-hung condensing combi doing domestic hot water and heat, or a hydronic radiant loop through a converted-loft slab. These systems are quieter, more comfortable, and less common than forced air, which is exactly why the average HVAC company doesn't want to touch them.
We do. Boiler repair is a specialty on our board. We service Viessmann, Navien, NTI, Weil-McLain, Buderus, and legacy Peerless and Slant/Fin equipment. Our techs read gas pressure with a manometer, check combustion with an analyzer, and diagnose control lockouts against the ignition sequence instead of just resetting the board and leaving.
For no-heat winter calls with a boiler we run the same 24/7 emergency dispatch as furnace service, with the specific equipment and parts on the truck.
What's included
Ignition failure, low water, high limit, and flame sensor lockouts traced to the real cause — often a dirty flame rod, blocked condensate trap, or failed circulator, not the control.
Expansion tank replacement, pressure reducing valve service, and air scoop / auto-vent replacement on systems that keep losing pressure.
Analyzer read-out and gas pressure verification on every service. Modulating condensing boilers especially need this — a badly tuned combi burns 15% more gas for the same heat.
Grundfos and Taco circulator replacement, zone valve rebuild, and low-voltage control troubleshooting.
Our process
- 1Emergency dispatch for no-heat.
- 2Diagnosis with a written quote before parts get pulled.
- 3TSSA-licensed gas work and analyzer-verified combustion on every visit.
Signs you need this service
- Boiler locks out and displays an error code within minutes of firing
- Pressure gauge reads below 12 psi or climbs above 25 psi
- One rad or one zone cold while the rest of the house is warm
- Water dripping from the pressure relief valve
- Boiler runs constantly but the house never gets warm
Frequently asked
My combi lost pressure and won't fire — is this fixable tonight?+
Usually yes. A one-time top-up on the manual fill loop will get you through the night in most cases, but recurring pressure loss means a leak or a failed expansion tank — worth a proper diagnostic visit.
Should I replace my cast-iron boiler with a combi?+
Not always. Cast-iron sectional boilers are simple, durable, and cheap to service. If yours is holding pressure and burning cleanly, replacement mostly makes sense at end-of-life or if you want to combine domestic hot water into a single wall-hung unit.
Do you service Viessmann and Navien wall-hung condensing boilers?+
Yes — both are among the most common downtown Toronto combi installs and we carry sensor and igniter parts for the current generations of each.