Boiler Repair in London, ON | Installation and Replacement
No heat, cold radiators or a combi boiler showing an error code? Our TSSA-registered gas technicians provide boiler repair in London, Ontario 24/7, plus boiler replacement and new high-efficiency installs.
Boiler Repair in London, Ontario: Heat Back On Fast
When your boiler stops in the middle of a London winter, waiting until next week is not an option. A boiler that won't fire, radiators that stay cold or a combi that keeps locking out can leave your home without heat and hot water within hours. Many older homes in neighbourhoods like Old North, Old South and Wortley Village still heat with radiators, and those systems need a technician who knows them.
Nova Drain & Plumbing Services London provides boiler repair in London around the clock. In Ontario, work on gas appliances must be done by a licensed gas technician, so every gas boiler repair, replacement or installation we take on is handled by our TSSA-registered team. We find the cause, explain your options in plain terms and get the heat back on safely.
No heat right now? We answer 24/7, nights and weekends included.
(226) 756-1274Signs Your Boiler Needs Repair
Most boiler breakdowns give a warning first. If you notice any of these, call before a small fault turns into a cold house overnight.
Boiler Not Heating
The boiler won't fire, or it runs but the house stays cold. A faulty thermostat, ignition part or gas valve is often the cause.
Cold Radiators or Cold at the Top
Radiators that stay cold, or are warm at the bottom and cold at the top, usually point to trapped air, sludge or a failing circulator pump.
Boiler Losing Pressure
Pressure that keeps dropping, or climbs too high, can mean a hidden leak, a faulty expansion tank or a worn pressure relief valve.
Water Under the Boiler
Drips or puddles around the unit come from a leaking valve, fitting or seal, and on older boilers sometimes a cracked heat exchanger.
Banging or Kettling Noises
Rumbling, banging or a kettle-like sound often means scale or sludge is overheating water inside the heat exchanger.
Ignition Errors & Lockouts
A combi or high-efficiency boiler that shows error codes or keeps locking out needs a licensed gas technician to diagnose it safely.
Resetting the boiler again and again only hides the problem. If you see any of these signs, book boiler repair before the fault leaves you without heat on the coldest night of the year, when a cold house can also mean frozen pipes.
(226) 756-1274Our Boiler Services in London, ON
Searching for boiler repair near me? From a single faulty part to a full boiler replacement, every job is handled by our licensed gas technicians and finished with a safety, pressure and venting check.
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Gas Boiler Repair: diagnosis and repair of ignition, gas valve, thermostat, circulator pump, expansion tank and pressure relief valve faults on all major brands.
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24/7 Emergency Boiler Repair: no heat in the middle of the night? We answer no-heat calls 24/7 across London, weekends included.
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Boiler Replacement: when repairs stop making sense, we remove the old unit and size a new boiler to your home, radiators and hot water needs.
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High-Efficiency Condensing Boiler Installation: condensing boilers burn less gas than older models. For every boiler installation in London we handle the venting, gas line and condensate drain to code.
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Combi Boiler Installation & Repair: installation and repair of combi boilers that supply both heat and on-demand hot water from one compact unit, including Navien, Rinnai, Viessmann and IBC.
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Radiator & Hot Water Heating Systems: bleeding, balancing and repairing radiators, zone valves and circulator pumps so every room heats evenly.
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Annual Boiler Service: yearly cleaning, combustion and venting checks keep your boiler efficient and safe through a London winter. Looking for boiler service near me? Book it in early fall, before the first cold snap.
Thinking about a new boiler? You get a clear, upfront quote before any work starts.
Boiler Brands We Repair & Install
Our gas technicians service major residential boiler brands found in London homes, including conventional, high-efficiency and combi models. We diagnose heating faults, repair damaged components and install replacement boilers suited to your home.
Navien Combi Boiler Repair & Installation
Navien combi boiler not heating, losing hot water or showing an error code? We repair and install Navien combi boilers across London, from ignition and flow problems to a full replacement sized to your home.
Don't see your brand? We repair most residential gas boilers in London, Ontario.
Brand names and logos belong to their respective owners. We are an independent boiler repair company, not an authorized dealer of these manufacturers.
Book Boiler RepairBoiler Repair or Boiler Replacement?
Not every breakdown means a new boiler. After diagnosing the problem, our gas technician explains whether a repair makes sense or whether replacing the boiler will save you money and trouble in the long run.
Usually a Repair
- A single failed part: igniter, flame sensor, gas valve, thermostat or circulator pump
- Pressure problems caused by an expansion tank or relief valve
- Air or sludge in the system leaving radiators cold
- The boiler is still fairly young and has had few breakdowns
Time for Boiler Replacement
- A cracked or leaking heat exchanger
- Repeat breakdowns every heating season
- The boiler is 15 years old or more and parts are hard to find
- Gas bills keep rising while the house heats unevenly
Looking for boiler replacement near me in London? We size the new boiler to your home and radiators, and give you an upfront quote before any work starts.
(226) 756-1274Combi vs Conventional Boiler: Which Is Right for Your Home?
A combi boiler heats your home and makes hot water on demand from one compact wall-mounted unit, with no separate tank. A conventional boiler heats the radiators only, and hot water comes from a separate water heater or storage tank. Both work well in London homes; the right choice depends on your space and how much hot water you use at once.
Heat + hot water in one unit
Combi Boiler
Best for
- Homes with one or two bathrooms
- Freeing up basement space by removing the hot water tank
- Replacing an old boiler and water heater at the same time
Less ideal when
- Several showers often run at the same time
Heat only, separate hot water
Conventional Boiler
Best for
- Larger homes with three or more bathrooms
- Households that use a lot of hot water at once
- Homes keeping a water heater that still has years of life left
Less ideal when
- Basement space is tight and you want to lose the tank
Is a Combi Boiler Worth It?
For most smaller and mid-size London homes, yes. You get heat and endless hot water from one unit, lower standby losses with no tank to keep hot, and more room in the basement. If your household often runs two or three showers at once, a conventional boiler with a separate hot water supply usually performs better. We check your hot water demand and incoming water flow before recommending either option.
Only need hot water, not heating? See our water heater repair & installation service.
Boiler Not Working? What To Check First
Before you call, a few quick checks can sometimes get the heat back on, or at least help our technician find the problem faster.
Smell Gas? Skip These Steps
If you smell rotten eggs or sulphur, do not touch light switches and do not try to reset the boiler. Get everyone out of the house and call the Enbridge Gas emergency line at 1-866-763-5427 or 911 from a safe distance, such as a neighbour's home. If your carbon monoxide alarm goes off, leave the house and call 911.
Thermostat
Make sure it is set to Heat and a few degrees above room temperature. Replace the batteries if the screen is blank.
Power
Check that the boiler switch near the unit is on and the breaker in your electrical panel has not tripped.
Gas Supply
See if your stove or other gas appliances work. The gas valve handle by the boiler should sit in line with the pipe.
Pressure Gauge
If the needle sits below the normal range marked on the gauge or boiler label, low pressure may be causing a lockout.
Reset Once
Press the reset button one time. If the boiler locks out again, stop and call a technician instead of resetting repeatedly.
Still no heat? Our licensed gas technicians handle boiler-not-working calls 24/7 across London, Ontario.
(226) 756-1274How Our Boiler Repair in London Works
Four clear steps from the first call to a warm house, with no guesswork and no surprises on the bill.
Diagnose
We test ignition, gas supply, pressure, circulation and controls to find the real cause, not just the symptom.
Honest Options
You get a clear, upfront quote and a straight answer on whether repair or replacement makes more sense.
Licensed Work
A licensed gas technician from our TSSA-registered team completes the repair or installation to code.
Safety Check
We test for gas leaks, check venting and system pressure, and confirm every radiator is heating before we leave.
Boiler Repair Reviews from London Homeowners
"Our gas boiler kept losing pressure, and the radiators weren't heating properly. Nova Drain & Plumbing Services London came out to inspect it and found a problem with the expansion vessel. The technician repaired the fault, checked the system pressure and made sure the heating was working again. He explained everything clearly."
Garnet P.
Old South, London, ON
September 22, 2026"We decided to replace the old boiler in our Byron home after several breakdowns. The team inspected our existing setup and helped us choose a suitable replacement. They installed the new wall-mounted boiler, checked the gas and water connections, and walked us through the controls. The installation was organised, and the utility room was left tidy."
Russell G.
Byron, London, ON
June 14, 2026"We booked our annual boiler service before the heating season. The technician checked the burner, inspected the condensate drain and tested the boiler's operation. He noticed a small issue with the condensate trap and dealt with it during the visit. I appreciated the maintenance advice and the clear explanation of what had been checked."
Fatima K.
Masonville, London, ON
March 9, 2026"Our boiler stopped heating the house during a cold January evening. We called Nova Drain & Plumbing Services London and explained that the unit kept shutting down. The technician inspected the ignition system, found the faulty component and repaired it. He stayed to check that the boiler was starting and heating normally before leaving."
Cecily V.
Westmount, London, ON
January 27, 2026"The display on our boiler kept showing a fault code, and the heating would stop every couple of days. The technician checked the circulation pump and related components instead of simply resetting the system again. He found the problem, completed the repair and explained what had caused the repeated shutdowns. Very thorough service."
Maude T.
Hyde Park, London, ON
February 18, 2026"I noticed a small puddle underneath our wall-mounted boiler and called to have it checked. The plumber found a leaking connection inside the unit and explained the repair before starting. After replacing the faulty fitting, he tested the system and checked for further leaks. The boiler has been running properly since the visit."
Boreal C.
Oakridge, London, ON
April 16, 2026Boiler Repair FAQ: London, Ontario
Why is my boiler not heating?+
The most common causes are a thermostat setting, a tripped breaker, low system pressure or an ignition fault. If the thermostat, power and gas supply are fine and a single reset does not help, the boiler needs a licensed gas technician to diagnose it safely.
Why does my boiler keep losing pressure?+
A boiler losing pressure usually has a small leak somewhere in the system, a failed expansion tank or a worn pressure relief valve. Topping it up only hides the problem for a while, so it is worth having the cause found before the boiler starts locking out.
Why are my radiators cold at the top?+
Radiators that are warm at the bottom and cold at the top usually have trapped air and need bleeding. If the air keeps coming back, or radiators stay cold at the bottom instead, the cause may be sludge, a pressure problem or a failing circulator pump.
How long does a boiler last?+
Most residential gas boilers last 15 years or more, depending on the model, water quality and how the system has been looked after. Once a boiler passes that age and starts breaking down every season, replacement usually costs less over time than repeat repairs.
How often should a boiler be serviced?+
Once a year, ideally in early fall before the heating season. Annual boiler service in London includes cleaning the burner and heat exchanger, checking combustion and venting, and testing pressure and safety controls. Many manufacturers also require yearly service to keep the warranty valid.
Is a combi boiler worth it?+
For most homes with one or two bathrooms, yes. A combi boiler gives you heat and on-demand hot water from one compact unit and frees up the space a hot water tank used. Homes that often run several showers at once are usually better served by a conventional boiler.
Should I repair or replace my boiler?+
Repair makes sense for a single failed part on a boiler that is not too old. Replacement is usually the better choice if the heat exchanger is cracked, the boiler breaks down every winter, it is 15 years or older, or gas bills keep rising. We give you an honest recommendation after diagnosing it.
Do you offer 24/7 no-heat service in London?+
Yes. Our licensed gas technicians answer no-heat and boiler repair calls 24/7 across London, Ontario, including nights, weekends and holidays. If you smell gas, leave the house first and call the Enbridge Gas emergency line at 1-866-763-5427 or 911.
How much does boiler repair or installation cost in London, Ontario?+
Repair cost depends on the part that failed and how long the diagnosis takes. Boiler installation cost depends on several factors:
- Boiler type: combi or conventional
- Size and heating output needed for your home
- Venting changes, especially when moving to a high-efficiency boiler
- Switching to a combi and removing the hot water tank
- Gas line and heating pipe changes
- Location and access to the boiler room
We inspect your system first and give you a clear, upfront quote before any work starts.
Book Boiler Repair in London
Our licensed gas technicians take no-heat calls 24/7 across London.
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