Boiler Won't Start — B2B Guide | Montréal Combustion

A boiler that won’t start in a commercial or institutional setting directly impacts comfort, production or building compliance. Before making assumptions, it is essential to distinguish between a demand-related shutdown (thermostat, schedule, interlock), a safety lockout (pressure, flame, ventilation) and a component failure (gas valve, ignition, controller).

What are the most common causes?

Possible causes include out-of-range water pressure, a circulation fault, a sensor or limit in alarm, a gas supply or ignition problem, or a deliberate shutdown (maintenance, construction). Any work on gas lines, combustion settings or burner disassembly must be performed by qualified personnel.

What can be checked without putting anyone at risk?

Without opening the burner enclosure or handling gas: confirm the demand at the control level (setpoint, schedule, emergency stop), record the codes or indicator lights displayed to relay to the technician, check water pressure if your procedure allows it, and note any auditory or olfactory anomalies. If you smell gas, follow your building’s protocol and contact authorized responders.

When should you call a professional?

Call as soon as a fault code persists after a single cautious reset per your operating manual, or immediately if there is a leak, a gas smell or any doubt about safety. Montréal Combustion serves Greater Montréal, the North Shore and the South Shore for B2B boiler service: structured diagnostics and return to service aligned with site requirements. 450-473-0909.

Frequently Asked Questions

Can I reset the boiler myself to get it running?

A simple reset can mask a safety or combustion fault. Without qualified diagnostics, repeated resets are not recommended. Contact a qualified team to identify the root cause.

Is low water always visible in the system?

Not necessarily. A slow leak, a closed valve or a makeup water problem can cause intermittent shutdowns. Checks should stay within your internal procedures and never involve burner or gas manipulation.

When should the situation be treated as an emergency?

Gas smell, significant water leak near electrical equipment, or any doubt about combustion integrity: evacuate if needed, shut down per your protocol, and call 450-473-0909 or the appropriate emergency services.