Homeowners just don’t get it. They expect their boilers to keep chugging along, year after year, decade after decade, with little or no maintenance. Then they complain when the 20-year-old boiler breaks down (usually in the middle of winter).

These same homeowners religiously change the oil in their car every 3,000 miles and are happy when the car lasts five years.

Something’s wrong with this picture. As an industry, we’re obviously not getting the message across to homeowners that their boilers need to be checked and maintained at least annually — still more often than that for oil boilers.

Unfortunately, investing in maintenance is something that many homeowners neglect to do.

Pay Me Now or Pay Me Later

A boiler that is not maintained regularly simply will not last. At the very least, there will be increased operating costs due to inefficient use of fuel and/or the replacement of hardware items.

In the worst case, safety is compromised and death, injury, and/or property loss could occur, says John Hoh, assistant director of inspections, National Board of Boiler and Pressure Vessel Inspectors (NBBI).

“Each type of boiler has its own unique problem areas. Steam boilers typically have more sludge and waterside corrosion problems than hot water boilers. Gas-fired boilers are typically cleaner on the fire side than oil-fired boilers, while copper tube boilers are usually easier to maintain on the water side,” notes Hoh.

Oil boilers have more particular maintenance concerns, because oil is a dirtier fuel and needs much more rigorous cleaning of the block. Oil loses its efficiency over a period of time, producing soot, and that soot adheres to the block.

“One of the byproducts of both oil and gas is sulfur dioxide,” says Steve Giordano, owner, Steven Giordano Plumbing and Heating, Boston. “In oil it comes out in higher concentrations.

“When you have humidity along with sulfur or sulfur dioxide, it forms a weak sulfuric acid. Combine that with soot and now you’ve got an etching of the block. That can easily rot through the iron.”

People who have oil-fired boilers often obtain their domestic hot water off of the boiler as well, which means it is running year round. For this reason, maintenance should be performed twice a year. It might be a good idea for a smaller tune-up during spring, with the more substantial maintenance check in the fall before heating season.

“A spring cleaning is a good idea, particularly if the cellar is humid,” says Giordano. “You don’t want to leave that soot sitting on the block and that humidity attacking it all summer.”

Look and Listen

The first thing Giordano does when performing regular maintenance on a boiler is to turn it on, look at it, and listen to it. If it’s a forced hot water unit, he listens to determine if the circulator is giving off any strange noises. A gravity system is obviously much quieter, and there he listens to the burner itself.

On a steam system, Giordano turns the boiler on and checks to see what the water looks like. “Is it jumping in the glass? Does it look dirty? Try to get a look through the sight glass to see if there’s any oil floating on the top. It’s often a good idea to draw some water out of the boiler, then just hold it to the light to see if you can see any rainbows.”

This is important because oil will float on top of the water, holding in the heat, and the water won’t be able to boil. This will cause water to surge up the returns more, and it can cause a lot of banging and spitting out of vents.

Once Giordano gets a sense of how the boiler sounds, he shuts it down. “If it’s a hot water system, I’ve learned not to believe the gauges. Even if a gauge is two years old, that does not guarantee it’s accurate. So I carry gauges with me that I periodically replace. Check the reading on the boiler, see if it jives with the boiler gauges.”

When comparing pressures, bear in mind that the boiler should be relatively cold, so only run the system initially for about 10 minutes. Then check to see if there’s sufficient pressure to get up to the top of the highest radiator and keep it pressurized.

Then check the expansion tanks. “On the pneumatic tanks, I just drain them right off the bat. If it’s a diaphragm style, I keep a tire gauge. There’s a little tire valve on it, so just check and make sure it’s at cold-fill pressure.

“A lot of guys don’t realize those come shipped from the factory at 12 psi. You’re supposed to pump them until you’re at cold system pressure, and you should be getting them up to 14 or 15 psi, not the 12 they’re shipped from,” says Giordano.

Don’t Forget the Controls

The controls keep the boiler humming along smoothly, so they should be checked during regular maintenance as well. The best thing to do is check the manufacturer’s recommended maintenance procedures.

Greg Roder, product specialist, McDonnell & Miller, Chicago, IL, notes that, generally, a probe-type low-water cutoff should be removed, inspected, cleaned, and/ or replaced annually.

“For mechanical feeders, remove and clean the strainer, remove and clean the cartridge, and replace it if necessary. For float-type controls, remove and inspect the float mechanism, clean and replace it if necessary. It’s obvious when it needs to be replaced,” says Roder.

Forced-circulation copper boilers have flow switches, and the flow switch needs to be taken out, inspected and cleaned annually, and replaced when necessary. In the case of the flow switch, check for deterioration of the paddles; replace the paddles if there’s any sign of deterioration, since it can affect the operation of the switch.

Contractors may neglect to check the controls because it’s kind of a pain to take off the probes and clean them. On steam boilers in particular, it’s a mistake to skip this step. “A steam boiler is right at that point where the water’s boiling,” says Roder.

“Think of when you boil water at home, and you end up with that nice little white ring around the pot. That’s the same thing that happens in a boiler. It’s not so much that we can make it any easier, it’s just you need to do it,” he says.

And when you’re done looking, listening, cleaning, and replacing, take the time to clean up after yourself, says Giordano. “When I’m done servicing a boiler, I get my ‘409’ out and I wipe the boiler down. It only takes me a minute.

“How can anybody do maintenance and leave the boiler looking like it belongs in the backyard? You should be cleaning up around yourself. Gas, for instance, might have scale around the bottom. You vacuum that stuff up.

“When you’re done, the homeowner will see it’s nice and clean, and they’ll feel they’ve gotten something for their money.”

Sidebar: Words of Wisdom

John Hoh, assistant director of inspections, the National Board of Boiler and Pressure Vessel Inspectors (NBBI), notes that contractors should check the following during a routine boiler maintenance call:

  • Check the fuel train for proper operation, leaks, and safety controls.
  • Check combustion operation and safety controls.
  • Check the boiler water chemistry to ensure proper water treatment, if necessary, is being performed.
  • Ensure that all safety devices on the boiler are operating as required and designed. This includes the safety relief valve, temperature or pressure controls, pressure gauge, thermometer (on hot water boilers), and low-water or flow-sensing devices.
  • Check for indications of leaks in the boiler and heating system.
  • Check for signs of overheating.
  • Check for proper exhausting of combustion gases.
  • Publication date: 05/28/2001