Steam Heat and Banging Pipes
What is Steam Heat?
Before we can get into why you're experiencing banging pipes, we need to understand what steam heating is and how steam heat works. Steam heating has been around since the late 1700's. Though the equipment has come a long way since then, the theory remains the same. If you have steam heat, you have a boiler in the basement and pipes that angle away from the boiler- the angled or pitched pipes are very important- more on that below. When your thermostat sees that the temperature in your home has dropped below the setpoint it sends a low voltage signal to the boiler to tell it it's time to go to work. Once the boiler sees this signal, depending on the age of your boiler, it will check that any safety switches fitted to it are reading ok. Assuming everything checks out safe, the burners will light. The lit burners will heat the water until it turns into steam just like a pot of water on your stove. That steam will then rise through the steam pipes in your basement heating the pipes and eventually the radiators.
Why Are My Steam Pipes Banging?
Now that we have a general understanding of how steam heat works we can begin to get into the root of the problem. As the steam is rising through the pipes and into the radiators, it is giving off it's heat. When the steam gives off enough heat, it will condense back into water. That water runs back down the piping to the boiler to start the cycle over again.
So this all sounds pretty simple right, what's the problem?
The problem is that as these systems and the homes they're installed in settle and move around a little bit the angle or pitch of the pipes leaving your boiler can change. Maintaining the pitch of your pipes is critical to get all of the water that condenses in the radiators and piping to flow back to the boiler. If we loose pitch in our piping system we can end up with water pooling in the piping. When your boiler first begins producing steam, that steam moves extremely quickly through the piping system. This fast moving steam will push any pooled water in it's path and get water moving extremely fast as well. The banging comes when that fast moving steam pushes that pooled water into the walls of the piping. This is why, in most cases, when you experience banging in your pipes, it happens shortly after the boiler starts up and then calms down a bit.
In some more rare cases, the banging can persist throughout the entire run cycle of the boiler. This typically points to a more complex problem. Most often we find that when a system has an extreme case of banging and clanging pipes that persists through the entire run cycle the root cause lies in how the piping nearest to the boiler is made up. The near-boiler piping, commonly called the header is crucial to the comfortable operation of the steam heating system. Different manufacturers and boilers have different rules around how the boiler should be piped but in general the piping coming directly off the top of the boiler should extend straight up to be at least 24 inches above the water line. This gives the steam time to de-couple from any entrained water which helps to ensure that only superheated steam is introduced into the header. After the superheated steam enters the header, the location of the tee's connecting the distribution piping is critical to the quiet operation as well. The tees must be located so that only superheated steam enters the distribution system.
Can I Fix This?
Absolutely! In fact, if you only experience slight knocking or banging when the heat first kicks on, here's an easy starting point for DIY weekend warriors - no special equipment or knowledge required!
Step 1) Pinpoint the radiator or radiators that are causing the noise.
Step 2) You'll need a couple of small pieces of 3/4" thick wood and a buddy.
Step 3) Cut 3 pieces of wood to the same size. The pieces should be cut so that they can be placed under both feet of the radiator on one side.
Step 4) Carefully lift the side of the radiator with the steam valve and slide one of your pieces of wood under the feet. The piece of wood should be evenly spaced so that both feet of the radiator safely and securely rest on the wood. WARNING- Radiators can be extremely heavy- lift carefully. There is also piping attached to the radiator, if the radiator won't lift, don't force it.
Step 5) Repeat step 4 on the other side. Start with one piece of wood but if you need too, you could add a second if it will fit.
Elevating the radiator as little as 3/4" can restore pitch to your distribution pipes and eliminate pooling. You should always be careful when doing this. Radiators can be extremely heavy. It is also important to remember that there is piping attached tot he radiator so be gentle when lifting. If your radiator won't lift, don't force it. Only licensed professionals should ever manipulate gas lines or touch the electrical side of your heating system.
What Do I Do If I Have Extreme Banging?
If you experience persistent, loud, obnoxious banging, don't worry! Comfort Craftsmen Mechanical has helped countless families quite down their steam heating systems so they can enjoy piece and quiet in their homes. No matter how bad your system is, we can quiet it down. From small pitch problems to large re-pipes, component replacements to cleanings, our experienced steam technicians are here to help. Give us a call HERE or schedule your visit online HERE to get started!
Steam Heat Replacements
If your steam heating system is old, loud and expensive to operate, Comfort Craftsmen Mechanical is here to help with high quality steam heating replacement options. Most residential steam boilers installed between 1970 and now were originally designed as hot water boilers with a couple of small changes made to to allow them to work as steam boilers. Here at Comfort Craftsmen Mechanical, we proudly install Burnham SteamMax steam boilers. The Burnham SteamMax boiler is the only residential steam boiler currently on the market that was designed from the ground up as a steam boiler. The SteamMax features several improvements over conventional hot water boilers modified by the manufacturer for use with steam that provide improved comfort, reliability and efficiency. Comfort Craftsmen Mechanical provides no cost quotes for system replacement. Give us a call HERE or schedule your no cost assessment online HERE.
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