Steam Boiler Maintenance

Helpful Hints to Maintain Your Steam Boiler

If you happen to have one of these beautiful creatures in your basement, there are things you can and should do on a weekly basis to keep your steam boiler in top condition. There are also things that you should not do which should be left to your regular service technician. He will have his own checklist of service items to follow when performing your fall checkup (A must item on your to do list is to make sure the fall checkup is done.) Every year I replace two or three steam boilers because weekly homeowner maintenance and fall checkups by a qualified mechanic are not done.

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Tips for Maintaining Your Steam Boiler

  • First - that you have the proper tools on hand to perform your weekly maintenance.
  • Secondly - wear the right clothes. Your weekly time ‘communing’ with your boiler is definitely not fashion hour. Wearing light colored khaki pants and brand new white tennis shoes that might get splashed with hot, dark brown boiler mud would not be a good idea. Nor are your basic flip flops and swim trunks suitable. The piercing screams from the hot boiler liquid bouncing off your bare feet and legs may cause members of your family or neighbors to dial 911. It can be embarrassing when the paramedics show up in your driveway.
  • Third - select a regular time. You always have to keep in mind that if it can go wrong, it will. You don’t want to have to call your service company at some weird, overtime hour to bail you out because you forgot your regularly scheduled, weekly boiler time. Suffice it to say that, if you’re a guy, Friday night, just as you’re heading out the door in your white tux to celebrate your wife’s birthday, would not be a good time to say to her, “Just a minute sweetie, I just have to go to the basement for a second to let a little water out of the boiler.” We all know how the nights going to turn out, right guys?


  • A boiler bucket, such as an old fashioned, 2 ½ gallon galvanized bucket with a strong metal handle works nicely.
  • Heavy work gloves so you don’t burn your hands are a good idea.
  • A screwdriver and a pair of allen's or channel locks would be handy in case you need to loosen nuts or screws.


Observe. Your steam boiler has at least two devices designed to be looked at. The first and most important is the gauge glass. This gauge glass will be on the side of the boiler. It is a glass tube about ⅝” in diameter and about 8-10” high. A good rule of thumb is to see the water level about halfway up the gauge glass. A completely full gauge glass or an empty gauge glass indicates a problem and you should speak with your boiler service company.

Most low pressure steam boilers operate in the range of 0.5 PSI to 1.5 PSI (a half a pound to a pound an hour). Don’t be alarmed if you don’t see the needle on the gauge move much. If they needle is up in the 2-5 pump area, you should check with your boiler service company.

Depending on the make and age of your steam boiler, your maintenance list may look different than someone else’s:

Original Cast Boilers (such as American Radiator)

If you have an original cast boiler, such as an American Radiator, you may have a gas conversion burner (Roberts-Gordon or Republic were two of the best), a pressure control, a pressure gauge, a relief valve and a drain valve. Your boiler will have a gauge glass and gauge glass valves and at the least, a manual fill valve. Your maintenance responsibilities in this case are very few. Drain a bucket of water from the boiler and dump it down your floor drain. This practice helps keep sludge off the bottom ot the boiler so you get better heat transfer into the water. It also keeps the drain port clear.

Replace the water you have drained with your manual fill valve. Your gauge glass should register about half full. Ideally, you should not be adding water to your boiler at other times during the week. If you are doing so, you probably have a steam leak on a valve or steam vent which should be corrected.

Next-Gen Boilers (Bee-Line or American Standard)

The next generation of steam boilers, such as Bee-Line or American Standard, might have a low water cutoff which requires weekly maintenance. One of the most common low water cutoffs is the #67 McDonnell Miller. A combination low-water cutoff and feeder such as the McDonnell Miller #47-2 is also common. These devices will have either a round, spring loaded handle or a yellow all valve handle. It is important to open these at least weekly to clean mud and sediment from the float chambers of these devices. These devices have a float inside which must operate free and clear in order to function when needed. Generally, draining a bucket of water will suffice.

You may find these two devices installed on boilers manufactured well into the late 1990’s. I find it helpful to dump water from the low water cutoffs while the boiler is firing. In this way you are checking its operation as well as flushing it out. The sudden release of water from the float chamber of the low water cutoff will cause the float to drip and trigger an electrical switch to shut of the gas.

How to Add Water To Your Boiler

While boiler running on water is common knowledge, most people forget to check the levels of water. During your routine boiler maintenance or checkup, it’s important to see that the system has enough water. For every 1 psi that appears on the gage, the water level rises up to about 2.31 feet. In general, 15 psi is a good number.

If the boiler water levels are low, the high temperatures might heat the steel and weaken it. This can lead to warped metal, cracks, and leaks. Save yourself from this headache by making sure your boiler has enough water.

Steps for adding water to the boiler:

  • Turn off the heat from the thermostat and wait for boiler to cool. You never want to add water while the boiler is still hot.
  • Check the water levels through the sight glass. Water levels should be within one inch of the center.
  • Pull the handle of the water feed valve and watch the sight glass as water flows through. Once the meter is at the appropriate level, you can push the handle of the feed valve up to close it.

Why Boiler Maintenance is Important

I estimate that I replace at least three boilers a year that are in otherwise good operating condition simply because low water cutoffs are not regularly checked.

So, these are things you can do yourself to prolong the life of your boiler. Get familiar with your boiler and get used to doing the basic maintenance items. Although they might look a little scary at first, you’ll come to love the heat they provide. Your local boiler specialist at Wilson Plumbing & Heating, Inc. will be happy to walk you through these steps during the fall check up.

Call Wilson Plumbing & Heating, Inc today at (330) 400-3334 or contact us online to schedule a steam boiler maintenance or repair service in Akron!