A boiler can run for many years with little attention, which makes it easy to skip maintenance. In Minnesota, your boiler may run from October into May. An annual check before that season starts catches safety problems, keeps the system efficient and lowers the chance of a no-heat call on a sub-zero night.
Why annual service matters
The U.S. Environmental Protection Agency advises having a trained professional inspect, clean and tune up your central heating system, including flues and chimneys, every year. This is part of its guidance in the EPA guide to carbon monoxide and indoor air quality. A gas or oil boiler that is out of adjustment, or has a blocked or leaking vent, can release carbon monoxide into your home.
Annual service also helps with:
- Efficiency. A dirty burner or heat exchanger wastes fuel.
- Reliability. Worn igniters, sensors and pump parts can be found before they fail.
- Equipment life. Hydronic systems can develop corrosion that clogs components, so catching it early protects the boiler.
- Warranty. Many manufacturers require professional maintenance. Check your boiler's warranty terms.
What a technician checks on every boiler
The exact steps depend on the make, model and fuel, and the technician should follow the manufacturer's maintenance instructions. A thorough visit typically includes:
- Inspecting the vent pipe and chimney connection for blockage, leaks, corrosion and proper slope
- Testing for carbon monoxide and flue gas spillage
- Checking gas connections and gas pressure, or the oil supply and filter on an oil boiler
- Inspecting and cleaning the burner and checking flame and combustion
- Inspecting the heat exchanger for cracks, leaks and deposits
- Testing the ignition system and flame sensor
- Checking safety controls, including the high-limit control
- Checking electrical connections and the thermostat
Hot-water boiler checks
The Department of Energy lists these tune-up items for hot-water systems in its Department of Energy HVAC guide for homeowners:
- Bleeding air from radiators
- Testing the pressure-relief valve and the high-limit control
- Confirming the expansion tank has the correct air charge
- Cleaning the heat exchanger
On a condensing boiler, the technician should also clean the condensate trap, inspect the condensate drain and neutralizer, and check the intake and exhaust vent terminations outside. The circulator pump, system pressure and any water treatment should be checked as well.
Steam boiler checks
Many older homes in St. Paul and the surrounding suburbs still heat with steam. For steam systems, the same Department of Energy guide lists:
- Draining some water to remove sediment
- Testing the low-water cutoff and high-limit controls
- Adding water treatment chemicals as needed to control deposits and corrosion
- Replacing clogged air vents and sticking steam traps
The low-water cutoff is a key safety device. It shuts the burner off if the water level drops too low.
What you can do between visits
These tasks are safe for most homeowners:
- Keep the area clear. Do not store boxes, paint, cleaners or laundry near the boiler. It needs air for combustion and space for service.
- Bleed hot-water radiators at the start of the season with a radiator key while the system is cool. Close the valve when water comes out steadily.
- Watch the gauges. On a hot-water boiler, note the normal pressure reading so you notice a change. On a steam boiler, check that water is visible in the sight glass.
- Look for leaks around the boiler, valves, radiators and the relief valve pipe.
- Keep outdoor vents clear. If your boiler vents out a side wall, keep snow, ice and drifts away from the intake and exhaust pipes after storms.
- Test carbon monoxide alarms. Minnesota law requires a working carbon monoxide alarm within 10 feet of each room used for sleeping, under Minnesota Statutes section 299F.51.
Leave these tasks to a technician: opening the burner compartment, adjusting gas pressure or controls, adding water to a hot steam boiler, and draining or refilling a hot-water system. Do not cap or plug the pressure-relief valve, even if it drips. If you smell gas, leave the house right away, do not use switches or phones inside, and call 911 and your gas utility from outside. If a carbon monoxide alarm sounds, get everyone outside and call 911.
When to call a professional
Schedule maintenance once a year, ideally in late summer or early fall before the heating season begins. Book a visit sooner if the pressure reading changes, water appears around the boiler, radiators heat unevenly, you hear new noises, or the boiler shuts off and restarts often. Krinkie's offers boiler maintenance and tune-ups for hot-water and steam systems. If problems turn up during the inspection, our technicians can handle boiler repair on the same equipment.
Common questions
How often should a boiler be serviced?
Once a year. The EPA recommends an annual professional inspection, cleaning and tune-up of central heating systems, including flues and chimneys.
When is the best time to schedule boiler maintenance in Minnesota?
Late summer or early fall, before the heating season starts. That gives time to complete any repairs before cold weather.
Can I bleed my own radiators?
Yes, on a hot-water system. Use a radiator key with the system cool, hold a rag under the valve, and close it when water flows steadily. Steam radiators use automatic vents and are not bled this way.