Common Boiler Problems & Repairs
Whatever your boiler is doing — no heat, no hot water, leaks, strange noises, lockouts or a gas smell — find the likely cause and get licensed, same-day repair across Greater Vancouver.
Call (604) 359-1081Emergency
5Gas Smell From BoilerA gas smell near your boiler is an emergency.Carbon Monoxide AlarmIf your carbon monoxide alarm sounds, get everyone outside into fresh air and call 911.No-Heat EmergencyNo heat in winter — especially with infants, elderly or medically vulnerable people, or freezing temperatures — is an emergency.Burning Smell From BoilerA burning, electrical or plastic smell from a boiler can mean overheating wiring or a failing component — turn the boiler off at the switch and call for urgent service.Boiler Made a Loud BangA loud bang on ignition (a “whoomph” or backfire) usually means delayed ignition — raw gas building up before it lights.
No Heat
7Boiler Not HeatingIf your boiler runs but there’s no heat, the most common causes are a failed circulator pump, a stuck diverter or zone valve, low system pressure, or a thermostat/control fault.Radiators Not Getting HotRadiators that stay cold while the boiler runs usually point to trapped air, sludge build-up, a failing circulator pump, or stuck valves.Some Radiators Cold, Others HotWhen some radiators heat and others stay cold, the system is usually unbalanced, airlocked, sludged in places, or a zone valve has failed.Boiler Won't Turn OnA boiler that won’t turn on at all is usually a power, fuse, transformer or control-board issue — or a thermostat that isn’t calling for heat.Boiler Turning On and Off (Short Cycling)Short cycling — the boiler firing and stopping every few minutes — is usually caused by overheating from poor circulation, a faulty thermistor or pressure sensor, a waterlogged expansion tank, or an oversized boiler.Boiler OverheatingAn overheating boiler usually trips its high-limit and locks out.Boiler Not Responding to ThermostatIf your boiler ignores the thermostat, the cause is often dead thermostat batteries, a wiring or pairing fault, or a control-board issue.
Hot Water
5No Hot WaterNo hot water from a combi boiler is usually a failed diverter valve, flow sensor, or a scaled plate heat exchanger; on a system boiler it can be the cylinder, pump or controls.Lukewarm Hot WaterLukewarm or not-hot-enough water on a combi boiler is most often a scaled plate heat exchanger or a partly stuck diverter valve.Hot Water but No HeatingWhen you have hot water but no heating, the burner clearly works — so the cause is usually a stuck diverter valve, a failed circulator pump, low pressure, or a control/thermostat fault on the heating side.Hot Water Temperature FluctuatingHot water that swings hot and cold (the “cold-water sandwich”) is usually a scaled plate heat exchanger, a faulty flow sensor, or a sticking diverter.Slow to Get Hot WaterIf hot water takes a long time to arrive, the cause may be a sluggish flow sensor or diverter, scale, or simply long pipe runs.
Leaks & Pressure
7Boiler Leaking WaterA leaking boiler should be checked promptly — common sources are the pressure relief valve, a failed pump seal, corroded pipework, the expansion tank, or a cracked heat exchanger.Boiler Losing PressureA boiler that keeps losing pressure usually has a small leak somewhere in the system, a failed expansion tank, or a leaking pressure relief valve.Boiler Pressure Too HighHigh boiler pressure (above ~2.Water Pooling Under the BoilerWater collecting under a boiler is often a blocked or overflowing condensate trap/pump, a relief-valve discharge, or a pipe/seal leak.Leaking RadiatorA leaking radiator commonly leaks at the valve, the spindle, or through corrosion pinholes, and it drops your boiler pressure.Pressure Relief Valve DrippingA pressure relief valve that drips (often from an outside discharge pipe) is usually doing its job because pressure is too high — typically a failed expansion tank — or its seat is worn.Boiler Keeps Needing Topping UpIf you have to top up boiler pressure every few days, there’s a leak in the system or a failed expansion tank — repeated top-ups only mask it and add oxygen that corrodes the boiler.
Noises
5Boiler Banging / KettlingA boiler that bangs, rumbles or “kettles” (like a boiling kettle) usually has limescale or sludge on the heat exchanger causing hot spots, or restricted flow.Boiler Gurgling NoiseGurgling from a boiler or radiators usually means trapped air in the system, low pressure, or — in cold weather — a frozen condensate pipe.Boiler Whistling NoiseA whistling boiler is often caused by scale or restricted flow, trapped air, incorrect gas/combustion, or a failing pump.Boiler Humming / VibratingA humming or vibrating boiler is usually a failing pump or fan, worn bearings, or a loose mounting.Heating Pipes Knocking / BangingKnocking or banging pipes when the heating runs is usually thermal expansion against fixings, trapped air, or high flow temperature.
Ignition & Flame
6Boiler Won't IgniteA boiler that won’t ignite usually has a cracked igniter, worn ignition electrode, faulty ignition control, gas-supply issue, or a flame-sensing fault causing lockout.Pilot Light Keeps Going OutOn a standing-pilot boiler or water heater, a pilot that won’t stay lit is almost always a failing thermocouple, a dirty pilot, or a draft.Boiler Keeps Locking OutRepeated lockouts mean a safety control is stopping the boiler — commonly ignition failure, flame loss, low pressure, a fan/pressure-switch fault, or overheating.Boiler Clicking but Not IgnitingClicking with no light-off usually means the igniter is sparking but the gas isn’t lighting — a worn electrode, incorrect spark gap, faulty gas valve, or gas-supply issue.Boiler Flame Keeps Going OutA boiler that lights then drops out seconds later usually has a dirty or failed flame sensor, a poor ground, or a gas/combustion fault — so the control can’t prove flame and shuts off.Yellow / Sooty Boiler FlameA boiler flame should be crisp blue.
Controls & Electronics
4Boiler Showing an Error CodeA boiler error code is a clue, not a diagnosis — the same code can have several causes.Boiler Display Blank / DeadA blank boiler display usually means no power (breaker/fuse), a failed transformer, a faulty display/interface, or a control-board fault.Boiler Keeps Needing a ResetNeeding to reset the boiler regularly means a recurring fault is tripping a safety lockout — commonly ignition, flame-sense, pressure or fan issues.Boiler Reset Not WorkingIf the boiler won’t reset, the underlying fault is still present (it won’t clear until fixed), or there’s a control/power problem.
Cold Weather
3Frozen Condensate PipeA frozen condensate pipe is the most common cold-snap boiler fault — the boiler locks out, often with a gurgling sound.Boiler Not Working in Cold WeatherA boiler that only fails in cold weather is most often a frozen condensate pipe, but wind-affected flue/pressure-switch faults and weak ignition can also show up in the cold.Boiler Condensate LeakA condensate leak (clear, mildly acidic water from the boiler) usually comes from a blocked or cracked trap, a failed condensate pump, or poor drainage.
Efficiency & Age
3High Gas Bills From the BoilerRising gas bills can come from a boiler losing efficiency — scale, poor combustion, a disabled outdoor reset, sludge, or short cycling — or simply an aging unit.Boiler Keeps Breaking DownA boiler that keeps breaking down may have an unresolved root fault, accumulated sludge damaging parts, or simply be near end of life.Repair or Replace My Boiler?As a rule of thumb, replace rather than repair when the boiler is over ~15 years old, facing a major repair (heat exchanger, control board, multiple parts), inefficient, or breaking down repeatedly.
Parts Are Professionally Installed — Not Sold for DIY
For your safety and to keep your manufacturer warranty valid, BoilerPart.ca does not sell loose boiler parts over the counter or for self-installation. Under BC regulations, gas appliance components must be installed by a licensed gas fitter. Every part we source is genuine OEM and is professionally fitted, tested, and certified by our Technical Safety BC–licensed technicians as part of a complete repair or installation.
Our Guarantees & Warranties
Every repair and installation is backed by genuine parts, licensed workmanship, and a promise to make it right.
Workmanship Guarantee
Every repair and installation is backed by our written workmanship guarantee. If a part we installed fails because of our work, we make it right.
Genuine OEM Parts
We fit only manufacturer-original (OEM) components so your boiler performs to spec and keeps its factory warranty intact.
Manufacturer Warranty Honoured
As an authorised service provider for the brands we work on, our installs preserve and register your manufacturer parts warranty.
Licensed & Insured
All work is completed by Technical Safety BC–licensed gas fitters. We are fully licensed, bonded and insured for your protection.
Up-Front Pricing
You approve the diagnosis and quote before any work begins. No hidden fees and no surprise charges.
Satisfaction Commitment
Backed by the full HVAC resources of CanroHeat.ca and four decades of service in Greater Vancouver since 1985.
Not Sure What's Wrong With Your Boiler?
Describe the symptom and our licensed technicians will diagnose and repair it — same-day across Greater Vancouver.
A Division of CanroHeat.ca · Licensed Gas Fitters · Serving Greater Vancouver since 1985