How often does a boiler need to be serviced?

Once a year is the usual answer, and for condensing boilers and combis it is the maker's answer too. An older cast iron boiler is more forgiving, but it still burns fuel and still has a vent and safety controls that should be checked yearly. Tankless units can need flushing sooner than the yearly service, and the unit's own readings say when.

Does a combi or a condensing tankless need a service if it is running fine?

Yes, and the makers say so in the maintenance schedule that came with it. The drain line clogs, parts wear, the burner drifts out of adjustment, and on tankless, mineral builds up inside. That last one shows in the unit's own readings, because the flow it reports drops as mineral builds. When to flush your unit comes from that reading, not from the calendar and not from the town the house is in.

Do you service Navien, Rinnai and Viessmann units?

Yes. Our team services Viessmann and Weil-McLain boilers, and Navien, Rinnai and Bosch boilers and tankless units. Each maker has its own service menu, its own fault codes and its own maintenance schedule, and the visit follows the schedule written for that model. It makes no difference who installed the unit or where it was bought.

When in the year is the best time to have it done?

Before the heating season, in late summer or early fall. A fault found then can be fixed with the heat off and nobody cold, and parts can be ordered without a house waiting on them. The first cold night is when every system that was not looked at gets tested at once.

Is it worth servicing an old boiler we might replace in a year or two?

Yes, for two reasons. The safety side does not get less important as a boiler ages: the vent, the controls and the burner still need to be right for however long it stays. And a service is good information for the replacement decision, because it shows what is wearing and how the boiler is actually running.

What do we find out at the end of the visit?

What was found, what was cleaned or adjusted, and anything that is starting to wear and should be planned for, in plain words. The visit is written down, so the next one starts from what this one saw.

Services

Heating system service and maintenance

The visit made before anything is wrong. A yearly service for the boiler, the steam system, the combi or the tankless unit, done in the mild weeks so the first cold night is not the test.

Call (508) 380-2629 Request service

What it covers

The yearly service on the gas fired heating systems our team works on. Standard boilers, cast iron and steel, that vent up a chimney. High efficiency condensing boilers that vent through plastic pipe. Combi boilers that make the heat and the hot water out of one appliance. Tankless water heaters. And steam boilers, the older systems with a glass tube on the side and radiators that hiss, which still heat a good share of the older houses around here. That includes Viessmann and Weil-McLain boilers, and Rinnai, Navien and Bosch boilers and tankless units. All of it gets serviced.

It is a different job from a repair. A repair starts with a symptom. A service starts with a system that is working, and its purpose is to keep it that way: cleaned, checked and adjusted, with anything that is starting to wear found while it is still a small part and a planned visit.

This page is about when, not which. If the heat is already off, start at boilers and heating. If the problem is a code on a wall hung unit, start at high efficiency boilers and tankless. If it is the hot water, start at water heaters. This page is the visit that keeps all three of those calls from happening.

Wall hung condensing boiler piped to three zone circulator pumps on a painted wall, with a small tank mounted below and an indirect hot water tank to the right

Steam boiler with its sight glass, gauges and black iron piping, and a hot water storage tank behind it

What a service visit involves

Looking before touching. What the system is, what it has been doing, and anything you have noticed since the last visit. On a modern unit that includes reading its fault history, which records what it saw while nobody was watching.
Cleaning. The parts that build up deposits over a season, and on high efficiency equipment the small drain line that can clog and shut the unit down.
The burner and the controls. The flame and the ignition parts checked, then the system run through a heating call to confirm it starts, runs and stops the way it should.
Venting. The vent checked from the appliance to where it goes outside, because a vent that is blocked or loose is a safety problem before it is a heating problem.
Burner adjustment, where it applies. On equipment that calls for it, the burner checked and adjusted if it has drifted over the year.
Safety devices. The safety valve and the shutoff controls checked for what they are there to do.
Pressure, on hot water systems. System pressure checked and trapped air dealt with, so the system is not quietly losing water and taking on fresh water to replace it.
Water level, on steam systems. The water level checked where it should be, along with the control that shuts the boiler off if it runs low. A steam boiler running short of water is the failure on a steam system that matters most.

Why yearly service matters

Efficiency. A burner that has drifted, a heat exchanger with a year of deposits on it, or a condensing boiler that has stopped condensing all burn more fuel for the same heat, and none of them announces itself. The difference shows up on the bill months later, with nothing to say why.

Safety. A heating appliance burns fuel inside the house. The vent that carries the exhaust out, the controls that shut the burner off and the safety devices that keep pressure and water level where they belong are exactly the parts nobody looks at until somebody does.

January. Most heating failures do not arrive out of nowhere. An igniter that is weakening, a pump starting to struggle, a clogged drain line or a pressure that keeps sagging give some warning first, and the service visit is when somebody is looking for it. Found in October, it is a part and an appointment. Found on the coldest night of the year, it is a house with no heat.

High efficiency equipment needs it most. A cast iron boiler forgives being ignored for years. This equipment does not, and the makers call for a yearly service in their own maintenance schedules, not as an extra.

On tankless there is a second job, and the unit tells you when it is due. A tankless unit heats water fast in a small space, so mineral builds up inside it much sooner than in a storage tank, and it needs flushing out. The first sign is in the unit's own readings: the flow it reports slowly drops, and most units show that in their service menu. Flushing on a fixed calendar guesses. Reading the unit does not.

Which supply the house is on is on the water bill, not on a map. Some MetroWest towns draw their water from the MWRA, which publishes its water as very soft. Natick pumps its own from town wells. Sherborn is on private wells. The right interval for any one house comes from what its unit reports, and the bill only says where to start looking. See where we work.

When to book it

Late summer or early fall, before the heat goes on for the season
The system has gone a year or more without a service
Nobody can say when it was last serviced
The company that installed it is gone, or no longer answers
You have just bought the house and inherited the system
Switching on and off over and over on a mild day
New noises, a kettle sound, banging or a burner that sounds rough
Pressure dropping and the system needing topping up
Fuel bills climbing with no change in the weather or the thermostat

How Connerney handles it

Licensed and insured. Licensed and insured in Massachusetts.
A record of the visit. What was found and what was done gets written down, so the next service picks up where the last one left off rather than starting from nothing.
The whole appliance. The burner, the controls and the venting as well as the pipe and the water side. Nothing gets handed to a second contractor.
Owner run. Bill Connerney owns the business, answers the phone and books the jobs, and our team of experienced plumbers does the work. Rated 5.0 on Google across 20 reviews, and BBB accredited since 2018.

Questions people ask

How often does a boiler need to be serviced?: Once a year is the usual answer, and for condensing boilers and combis it is the maker's answer too. An older cast iron boiler is more forgiving, but it still burns fuel and still has a vent and safety controls that should be checked yearly. Tankless units can need flushing sooner than the yearly service, and the unit's own readings say when.
Does a combi or a condensing tankless need a service if it is running fine?: Yes, and the makers say so in the maintenance schedule that came with it. The drain line clogs, parts wear, the burner drifts out of adjustment, and on tankless, mineral builds up inside. That last one shows in the unit's own readings, because the flow it reports drops as mineral builds. When to flush your unit comes from that reading, not from the calendar and not from the town the house is in.
Do you service Navien, Rinnai and Viessmann units?: Yes. Our team services Viessmann and Weil-McLain boilers, and Navien, Rinnai and Bosch boilers and tankless units. Each maker has its own service menu, its own fault codes and its own maintenance schedule, and the visit follows the schedule written for that model. It makes no difference who installed the unit or where it was bought.
When in the year is the best time to have it done?: Before the heating season, in late summer or early fall. A fault found then can be fixed with the heat off and nobody cold, and parts can be ordered without a house waiting on them. The first cold night is when every system that was not looked at gets tested at once.
Is it worth servicing an old boiler we might replace in a year or two?: Yes, for two reasons. The safety side does not get less important as a boiler ages: the vent, the controls and the burner still need to be right for however long it stays. And a service is good information for the replacement decision, because it shows what is wearing and how the boiler is actually running.
What do we find out at the end of the visit?: What was found, what was cleaned or adjusted, and anything that is starting to wear and should be planned for, in plain words. The visit is written down, so the next one starts from what this one saw.

Related services

Where we work

Based in Natick, working across MetroWest Massachusetts.

Plus the surrounding MetroWest towns. If you are nearby, call and ask.

Call us, or request service

Tell us what is going on. If no one picks up, leave a message and Bill will call you back as soon as he can. If it is easier to write it down, the form reaches the same place.

Call (508) 380-2629 or request service