Guide
Boiler maintenance checklist
What a pro should check each year, and what you can safely watch between visits.
Call Now Plumbing is a referral service. Your call is routed to an independent, locally run heating contractor who handles the visit.
For the yearly service visit
Angi lists cleaning, checking for leaks and low water, descaling, and replacing wear parts as typical service work, at $200 to $500 a year.[source] Ask also for a combustion and venting check, safety control tests, and on steam, a low water cutoff test.
Between visits
- Keep the boiler area clear.
- Test carbon monoxide alarms.[source]
- Watch the gauge or sight glass.
- Keep outside vents clear of snow.
- Bleed radiators that stay cold at the top.
About this guide. Written by Call Now Plumbing, a referral line operated by Get Called LLC, from the public sources listed on our sources page, checked Nov 3, 2026. It has not been reviewed by a licensed heating contractor. For advice on your system, ask the company you reach.
Why maintenance matters in the Mohawk Valley
NOAA's 1991 to 2020 normals for the Utica Oneida County Airport station show January averaging a high of 30 degrees and a low of 14 degrees, with about 140 nights a year at or below freezing.[source] A boiler here runs for most of the year. Small problems such as a dirty burner, a weak igniter or a waterlogged expansion tank show up on the coldest nights. Yearly service before the heating season catches many of them.
Fuel matters too. Oil heats about 13% of homes in Oneida County and about 22% in Herkimer County, and oil burners need more regular cleaning than gas.[source][source]
Gas boiler service checklist
- Inspect and clean the burner and combustion area
- Check the flame sensor and igniter
- Check gas pressure and the gas valve
- Inspect the heat exchanger for soot, scale or cracks
- Test safety controls, including high limit and low water cutoff
- Inspect venting from the boiler to the chimney or side wall
- Test for carbon monoxide and record combustion readings
- On condensing boilers, clean the condensate trap and check the drain and neutralizer
Oil boiler service checklist
- Replace the nozzle and fuel filter
- Clean the combustion chamber and heat exchanger
- Check and adjust the electrodes
- Check the fuel pump pressure
- Test the cad cell and primary control
- Inspect the oil tank and lines for leaks or corrosion
- Run a combustion test and set the air and fuel mix
- Check the chimney and barometric damper
Steam system checklist
- Check the water level in the sight glass, and clean the glass if it is cloudy
- Flush or test the low water cutoff according to the manufacturer
- Check the pressuretrol setting and clean its pigtail
- Check main vents and radiator vents
- Look for leaks on wet returns and near-boiler piping
- Skim the boiler if the water is oily or the level bounces
Hot water system checklist
- Check cold and hot pressure readings
- Check the expansion tank charge
- Inspect the relief valve and its discharge pipe
- Listen to circulator pumps for noise
- Check automatic air vents and bleed radiators if needed
- Check zone valves open and close correctly
Things you can do yourself
Keep the area around the boiler clear of storage, laundry and anything that can burn. Change the thermostat batteries each fall. Test CO alarms monthly.[source] Clear snow from side wall vents after storms. On steam, look at the sight glass weekly during the heating season. On hot water, glance at the pressure gauge now and then so you know what normal looks like.
Do not open the boiler, adjust gas pressure, or remove panels that require tools. Those are jobs for a technician.
Keeping records
Keep a simple log near the boiler: the date of each service visit, the company, what was done, parts replaced and the combustion readings. Note when you last bled radiators or added water. For steam, note the water level you see when cold. A log helps any technician, and helps you notice slow changes, like a steam boiler needing water more often.
When to call between visits
Call if the pressure or water level changes noticeably, if you see water under the boiler, if the boiler short cycles, if you smell exhaust or gas, if a CO alarm sounds, or if the boiler makes a new noise. Small changes caught early are cheaper to fix.
Frequently asked
How often should a boiler be serviced? Once a year before the heating season is the usual advice. Oil boilers benefit the most from yearly cleaning.Does a new boiler need service? Yes. Many manufacturers require regular service to keep the warranty valid. Check the warranty terms.Should I flush my steam boiler's low water cutoff myself? Some owners do this weekly or monthly with a float type cutoff, following the manufacturer's instructions. If you are not sure, ask the technician to show you during service.How long does a service visit take? It varies with the boiler and what the technician finds. A gas boiler in good condition usually takes less time than an oil boiler that needs a full cleaning.Fall startup checklist for owners
- Clear storage away from the boiler and the chimney or vent.
- Replace thermostat batteries.
- Test smoke and CO alarms.[source]
- For steam, check the sight glass and flush the low water cutoff if your manual says to.
- For hot water, read the cold pressure.
- Turn the thermostat up and listen to the first cycle.
- Walk the house and confirm each radiator or zone heats.
- Book a service visit if anything seems off, or if it has been a year since the last one.
Doing this in September or early October, before the first cold week, leaves time to fix problems while companies are less busy.
Spring shutdown
At the end of the heating season, many owners turn the thermostat down and leave the boiler on standby if it also makes hot water. If it heats only, you can turn it off. For steam, leave the water at the normal line. For oil, keep the tank from running very low over summer, since condensation can form in a near empty tank. Spring is also a good time to book next fall's service, because companies are less busy and you can pick a date that suits you. Write down anything odd you noticed during winter, such as cold rooms, noises or pressure swings, so the technician can look at it during the fall visit.
What a technician checks
A typical visit includes cleaning the burner and heat exchanger as needed, checking the flame, testing combustion and draft, testing safety controls such as the high limit and low water cutoff, checking the relief valve and expansion tank on hot water systems, inspecting the vent, and looking for leaks. Ask for a written list of what was done.
Common questions
How often should a boiler be serviced?
Yearly is the common advice. Angi calls routine service the most reliable way to catch small issues early.[source]
Want a pro to look at it?
Call and get connected with a local heating company.
Call about your boiler(888) 835-0429