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Heating the Water

While water management is one of the most important aspects of boiler operation, the other is being able to heat the water. Since the age of the steam engine, wood, coal, and oil have been the three main fuels used to boil the water. Each has their advantages and disadvantages, and this must be considered thoroughly for use at a retreat. In this discussion, oil will not be considered as a fuel; the reason for this is, like gasoline, it can be expensive to constantly replenish, needs large volumes of storage space, and takes refineries to process.

The first fuel that is commonly considered for use is wood. Most traction engines and small stationary boilers use wood, and their fireboxes are designed to most efficiently channel the heat. A wood burning firebox will be narrow and tall, allowing wood to be piled up inside to create a large burning mass. The bottom of the firebox will have grates for the wood to sit on, and these usually will be fixed and only can be removed when the boiler is cold for cleaning. A wood-burning steam engine will be the most useful for retreat purposes, as wood is the most common resource available to the average person. While the engines can have a large appetite for wood, they can also expedite the process of cutting, splitting, and moving wood to and from storage and can offset the extra needed supply. Just like with a woodstove, different types of wood will perform differently in a boiler. Pine and other softwood will burn very quick with high heat, but the fireman will have to constantly add more fuel to the fire. Hardwood will burn slightly cooler, but the wood will last longer and give heat over a longer period of time. Most often, boilers will be fueled with scraps of wood left over from other activities, since they are not picky about the size and type of wood used. Again, for our purposes, a wood-fired boiler would be the best option.

Coal is the other common source of fuel for boilers. While only some larger types of traction engines and stationary boilers are built to be fired with coal, most railroad locomotives built after the 1880s were designed to be fired with coal. A coal firebox will not be very deep, but rather will be wider and longer than wood fireboxes in order to give a large heating area. A coal fire works best when kept even and around three to four inches in depth. Piling coal too deep can cause cold spots in the firebed and lead to wasted fuel and less efficiency; keeping the firebed too shallow will cause holes in the fire and lead to uneven stresses on the metal and less efficiency as well. Likewise, if the coal has contaminants in it, such as mud or iron, clinkers can form where the impurities stick together. These clinkers can create a massive clump of waste. These have to be fished out of the firebox to prevent the fire from losing efficiency, as they block air from being pulled up through the fire, and they take up space where burning fuel needs to be. Coal fireboxes will have moveable grates that the burning coal sits on; these grates must be shaken from time to time to let the burned ash fall through them to keep the fire clean. While coal is currently very available, for our purposes it is not the first fuel of choice, as it must be transported to the retreat and can take up a large area for storage. However, it does not need to be refined as oil does, and it will store indefinitely without losing its ability to provide heat.

Regardless of whether the steam engine used will be fueled with wood, coal, or something else that can burn, the most important item is giving constant and careful attention to the way the boiler is operated. The water must be constantly added or taken away to maintain a safe level, and good firing by an experienced person is a must to obtain the best performance from the boiler. Once again, practical experience is the best teacher when it comes to firing a steam engine.

Lubricating the Boiler

Since the importance of water and fuel has been addressed, the next important step in operating a boiler is maintaining a good level of lubrication. Like any vehicle, vintage steam engines need constant oiling and greasing in order to keep operating. However, this is usually done by hand instead of a splash-oil method, and each moving part of an engine needs a different type of lubrication. The specific type of oil needed is called steam oil, as it is used to lubricate the cylinders, valves, and crossheads on an engine where steam will be applied. It is a heavy oil that is designed to be mixed with steam and can be injected into higher heat areas without being excessively thinned. It should be kept in a marked can and applied liberally to all higher temperature moving points. Too much oil is much less expensive and easier to replace than worn out and overheated metal. In common solid bearings, such as on old railcar axles or traction engine axles, regular used motor oil will suffice, if it is clean with no trash in it.

Greaseis also an important lubricant and can be used for crank shaft bearings and rod bearings. Soft grease is the easiest type to work with and can be applied with any common grease gun, but a hard grease called Alemite can be used when bearings will not be accessible for a long period of time, such as on a moving locomotive. Alemite grease comes in sticks and must be injected into bearings with a special grease gun and will release its lubricating properties continuously over an extended period of time. If an alemite stick drops on the ground, do not use it in the bearing, as it has picked up trash from whatever it was just dropped on, and it needs to be discarded. Just one grain of sand in the stick can ruin a perfectly good bearing. As with lubricating oil, liberally applied grease is better than not enough, and a large amount should be stored for use.

Like any vehicle with moving parts, these engines must constantly be inspected for wear and tear. Previously, problems such as scale and corrosion have been mentioned in this article, and these should be looked for on a constant basis. Frequent visual inspections are extremely important, and defects must be scoured for over all parts of the machine. Problems to look for include bulges, cracks, leaks, and wear on the firebox sheets and boiler barrel, which is the main part of the boiler. This includes pitting, grooving, corrosion, signs of overheating, mud, and trash in the boiler; it also includes any broken, cracked, and eroded staybolts, rivets, and fittings. Staybolts secure the firebox to the boiler and are fitted within a few inches of each other. They have a small hole in the center, which is used for inspection. No steam or water should be leaking or fizzing out of the hole, and nothing should be placed in the hole to plug it. If the staybolt is leaking, it means it is broken and should be replaced at the first opportunity. Bulging around the firebox is usually attributed to several broken staybolts in the same area and is very dangerous. If bulging is seen, the fire should be dumped immediately and the cause ascertained. Cracks in the boiler usually form first around corners and fittings, such as firebox corners, firedoors, washout plugs, and holes for appliances. Cracks are usually visible under steam, but inspection for them cannot be accomplished inside a hot firebox. Again, special care should be used when visually inspecting for trouble, and a person with a good eye and experience can spot them before they become a major problem. Most cracks can be repaired and welded up, but this should only be done by a person who has experience welding on boilers, as there are specific procedures that involve drilling holes in the steel to stop the crack before welding.

As technology advanced, better tools like hydrostatic tests and ultrasounding allowed better care of steam engines and boilers. Ultrasound machines are used to determine the thickness of the metal sheets of the boiler and firebox, and they are a must in the modern world for boiler inspections. This allows thin spots to be found and cut out and patched before problems develop or it fails catastrophically. Steam shows and railroad museums are excellent places to ask about ultrasound machines and who can perform them locally. This is a very specialized task and probably will not be as available during a societal breakdown, but if done regularly beforehand they can give you an idea about what is happening to the metal of the boiler.

Hydrostatic tests are another important boiler tool and are used to test boilers for soundness and strength before being pressured with steam. Water is forced into the boiler when it is cool and is pumped up to a pressure greater than the operating steam pressure. Different size boilers will have different pressures, and studies should be done to ascertain what pressure is appropriate for testing your particular boiler. The goal of hydrostatic tests is to determine if there are any weak spots, leaks, or cracks in the boiler before steam is built. If a part of the boiler does fail during the test, water will just come pouring out of the failure instead of having a boiler explosion. If a problem is found, the water can be drained immediately and repairs started, instead of wasting fuel and waiting for the boiler to cool down. This test is also done by a boiler specialist and must be done regularly while society is still well. Also, both tests will need to be done for inspection purposes and paperwork will need to be kept on the condition of the boiler, along with repair lists. Most states have their own boiler inspectors that come and declare if the boiler is safe or not. Also, the Federal Railroad Administration has agents that conduct their own tests on locomotives that are even more stringent than regular “hobby” boiler inspections.

Monitoring and Maintaining the Water Level

Remembering the most important thing, which is Do NOT EVER let the water drop below the top of the crown sheet, there are sight glasses mounted on the backhead (rear) of the boiler to monitor the amount of water, and these must be watched constantly. Most boilers have two sight glasses; both are connected to the boiler at the top and bottom and have notches in the glass to help observe how much water is in the boiler. They also have drains on the bottom for cleaning out trash in the sight glass. These sight glasses must be cleaned by draining repeatedly before every start up and must also be blown down (drained under pressure) at frequent intervals during operation to ensure that the water level reading is correct.

Another set of tools that are used to monitor the water level in the boiler are called tri-cocks. These are a set of three valves found on the right side of the boiler (faced from the rear) that are set up diagonally, stepped down from each other. Before startup, the procedure is to open each of these valves and let water drain out to observe where the level inside the boiler is. Under pressure, the valves can be cracked open to observe if water or steam comes out. There must always be water coming out of the bottom tri-cock for safety. Likewise, there must always be water visible in the sight glass. If none is visible, do not fire up the boiler without adding water. If none is visible under pressure, do everything possible to add water in the boiler, and take the precaution of removing or dumping the fire out of the firebox to remove the heat. I cannot stress enough the importance of not letting the water level get too low in the boiler. On the other hand, too high a water level can cause a problem called priming or carry-over, which is when the water is so high it goes into the engine with the steam and can damage the internals of the engine. The trick is to maintain a water level where it can always be seen in the sight glass.

Now that we have covered the aspects of how to ascertain the level of water in the boiler, it must be discussed how to add water to the boiler. When the boiler is cold, the whistle or tallest fitting on the boiler can be removed and water poured in with a hose or buckets until it is at a good level in the sight glass. Also, a pump can transfer water to the boiler, if it is feasible. When the boiler is hot and under pressure, the use of injectors and duplex pumps are the most common ways to add water. There are usually two injectors found on boilers. These work by taking steam out of the boiler, rushing it through a nozzle to create speed, and shooting it back into the boiler. On its way through the nozzle, the steam creates a vacuum, which picks up water from a pipe underneath the injector and shoots it into the boiler alongside the steam. The water pipes that are connected to the injectors run to large storage containers that need to be kept full of clean water. These can be rain barrels, large tanks, and troughs or wagons specifically designed to carry water. Traction engines and railroad locomotives always carry a supply of water with them when they journey off somewhere. The injectors are amazing but simple devices and will work efficiently when the boiler is under pressure. However, since they work on the principle of a nozzle creating velocity from pressure, they will cease to work if the boiler pressure drops below a certain PSI. Every injector is different and will stop working at different pressures, so gaining individual experience with them is vital. Every so often, they must be disassembled and the forcing cone reshaped or rebuilt, because the steam and water erodes it over time. Also, there should be screens placed in the water pipes leading to the injectors to trap trash, and these need to be inspected and cleaned every day to keep an unobstructed flow of water. Another critical part of the injector is where it pushes water into the boiler, called a boiler check-valve. This works like a backflow preventer in a water line, and it keeps steam from reversing its flow through the injector. It is a good idea to inspect the boiler check-valves at the same time the injector is inspected.

When injectors fail or are not enough to keep a safe level of water in the boiler, a device called a duplex pump or boiler feed water pump comes into play. This is a device that takes steam pressure or air pressure and forces water in the boiler at a fast rate using dual sets of pistons that pump both backwards and forwards, instead of just one way. Duplex pumps have two steam (or air) cylinders and two water cylinders. They can also be hooked up to a pressurized air system, in case the steam pressure is incredibly low or unavailable. These have personally been life savers when the steam pressure drops too low for the injectors to work, and they must be inspected and cleaned every so often to maintain effectiveness.

Managing Impurities

Since we have now covered briefly the importance of water and how to add it in the boiler, we must insure that the best water possible is put in the boiler. Impurities and chemicals in the water can cause problems, such as scale buildup, corrosion, and foaming; these problems will eventually become serious issues that compromise the safety of a boiler. Scale is caused by impurities in the boiler water that concentrate when the water is evaporated and cling to the metal surfaces in the boiler. Most often called precipitates, these build up on heat transfer surfaces and interfere with important heat transfer to the water, lowering the efficiency of the boiler. If left unchecked and untreated, the scale can also prevent the water from keeping the metal surfaces cool, such as on the boiler flues; thus, hot spots can form that can eventually cause local overheating and rupturing of the flues, leading to failure. Some common feed water contaminants include calcium, silica, lime, and iron. This kind of water is commonly known as “hard water”, which is very common in many places. The first way to treat hard water is to try to remove as many of the impurities as possible, such as running it through a softener or water purifier. Once it is ready to be feed water for a boiler, a chemical scale remover should be added. A common scale remover is called Scale Gone 35 and can be found from various sources. Inquiring at local steam shows or automotive restoration stores should also give several ideas of where to find a good scale remover, as it is also used to clean radiators and copper piping. Instructions on mixing solutions will be available from the provider, and it is wise to every so often look inside the boiler when it’s cool to observe if scale is collecting on the steel or to see if the remover is doing its job.

Corrosion in boilers is also another dangerous occurrence and can be treated by using the correct feed water and chemicals. The principle of corrosion is the reversion of metal to its original form of ore. In boilers it is usually caused by high oxygen content in the water and a low pH balance. However, the problem of corrosion is one of the simplest to treat, in terms of boiler applications. A deaerator can be used in the feed water to remove oxygen, but the easiest way to remove oxygen from water is to let it sit in the sun in a large open top tank. As the sun shines down on the water, it draws the oxygen up and out of it, rendering the water less likely to cause corrosion. To determine the pH balance, a water testing kit is essential and can be found at any swimming pool store. If the pH balance is low, a simple addition of approximately 1 pound of baking soda per 5000 gallons to the feed water can be used to maintain a neutral pH.

Foaming can be another troublesome aspect of boiler operation. Foaming occurs when solids and other impurities in the boiler water cause bubbles to form on the surface of the boiling water. This makes it very difficult to ascertain the water level in the boiler and can fool some operators into believing there is plenty of water in the boiler when it is actually at dangerous levels. Like the other solutions to boiler water problems, one of the first steps to ensure there are no solid deposits in the water is to filter it before it enters the feedwater supply. While there is no way to absolutely be rid of all the solids, there are ways to eject scum and deposits from the boiler. Each boiler is equipped with blowdown valves, which are usually located on each side of the firebox, to purge the boiler of any collected solids and trash. The boiler must be blown down regularly to get rid of the deposits, and if the boiler is foaming, alternating the use of both blowdown valves continually can help stop the creation of bubbles and help the water settle down.

While the largest danger of foaming is not knowing where the water level is in the boiler, it can also cause a condition known as priming or carryover. This is when water clings to the bubbles formed in the steam and is sent through the steam piping (called a dry-pipe) to the cylinders. Since steam engines work on the principle of expanding steam, there are very tight tolerances in the cylinders. If water, being non-compressible, is allowed to get into the cylinders, it can be forced by the pistons against the cylinder heads and cause the cylinder heads to crack or be blown off, rendering the steam engine useless. Other things that can cause priming is carrying the water in the boiler too high and changing the load on a boiler very quickly. When the throttle is opened, only steam should flow through the dry pipe; if the water level is too close to the top of the pipe or the load is suddenly increased, the vacuum created by the steam can carry water along with it to the cylinders. The best way to gain knowledge of where to carry the water in a boiler is, once again, familiarization and a lot of experience.