What a combi boiler does
A combination boiler, or combi, is a single wall-hung unit that does two jobs. It heats water for your radiators or in-floor heating, and it heats domestic water on demand for your taps and showers. There is no storage tank, which saves space in condos, townhomes and smaller mechanical rooms.
Because one appliance does so much work, a missed combi boiler service can leave you with no heat and no hot water at the same time. Regular maintenance is the simplest way to avoid that.
Why combi boilers need regular service
Combi boilers are compact and efficient, but they are packed with precise parts: a modulating gas valve, a fan, a condensing heat exchanger, a plate heat exchanger for domestic water, sensors, a pump and a pressure system. Small issues in any of them affect performance.
Even though Metro Vancouver water is soft, sediment and debris still build up over time in the heating loop and the domestic side. Condensate traps collect residue, and burners need inspection. Most manufacturers recommend yearly service, and following their maintenance schedule also helps keep the manufacturer's warranty in good standing.
What a thorough combi boiler service includes
A proper service visit goes beyond wiping the cabinet. Here is what a technician typically checks.
- Inspect and clean the burner and combustion chamber
- Test combustion with an analyzer and adjust if needed
- Clean the condensate trap and check the drain line
- Check system pressure and the expansion tank charge
- Clean inlet filters and screens on the water and heating sides
- Test the pressure relief valve, flame sensor and safety controls
- Inspect venting for secure joints, blockages and proper slope
- Check domestic hot water temperature and flow at a fixture
Common combi boiler problems and what causes them
Knowing the usual faults helps you describe the problem clearly when you call. Many have a simple cause.
- Low pressure: the gauge drops below the normal range and the boiler locks out. Causes include a small leak, a recently bled radiator or a failing expansion tank.
- Lukewarm or fluctuating showers: often a partly blocked plate heat exchanger or inlet filter, or a flow sensor problem.
- Boiler locks out with an error code: frequently ignition, flame sensing or a blocked condensate trap.
- Radiators cold but hot water works: could be a pump, diverter valve or air in the system.
- Gurgling or banging noises: trapped air, low water pressure or debris in the heat exchanger.
- Frozen condensate line: on outdoor-routed lines during a cold snap, a frozen drain can shut the boiler down.
Simple things owners can do between visits
You do not need tools for most of these, and they help a technician diagnose problems faster if you ever need one.
- Learn where your pressure gauge is and what the normal reading looks like when the system is cold.
- Write down any error code before resetting the boiler, and do not reset repeatedly if it keeps locking out.
- Keep the area around the boiler clear of storage boxes and cleaning products.
- Run the heating briefly in late summer so any problems show up before you really need heat.
- If you smell gas, leave the home and call FortisBC's emergency line from outside, then call us.
Repair or replace an aging combi?
Combi boilers can run reliably for a long time with care, but heat exchanger failure, repeated part replacements or parts that are no longer available are signs it may be time to look at a new unit. Your household may have also changed. If you have added a bathroom or have more people showering in the morning, a larger combi or a heat-only boiler with an indirect tank may suit you better.
Some owners also pair a new combi with ductless heat pumps for summer cooling and shoulder-season heat. We can talk through these options and give you a clear quote.
Combi boiler service from Able Pro
Able Pro services, repairs and installs combi boilers and conventional boilers in Coquitlam, Port Coquitlam, Port Moody, Burnaby, Surrey, Pitt Meadows and Maple Ridge. We explain what we find in plain language and quote any repairs before doing them. If your boiler fails in the middle of winter, our technicians are on call 24/7.
Late summer and early fall are ideal times to book. Call (236) 222-2222 or schedule online.