Q. I have a boiler connected with a stove which causes a terrible rumbling whenever they draw water from the cold faucet, and it is bound to burst the pipe or boiler somewhere. Connections are all heavy lead pipe. I send you sketch of work (Figure 114). Please advise me, and oblige.

I have marked where it bursts; it is street-pressure, and these are all the connections in the house which you can see; 1 1/4-inch iron pipe is used for water-heater. Do you suppose the trap in stove causes it?

A. We think there are several good reasons why the pipes or the boiler, especially the first, when made of lead, should burst in an apparatus designed as that shown in your sketch.

The bursts in the pipe are due to the changes the lead pipe is subjected to, by frequent and extreme changes of temperature under pressure, due to your boiler being too small for the water-back; or the state of your fire or the efficiency of your water-back is too great for the intermittent use that is made of the warm water.

When a kettle of water boils on the top of a stove and blows the cover off, or ejects steam and water from the spout, the cook removes the kettle or adds cold water. When she removes the kettle she places the water already in the kettle, which has received all the heat it should, beyond the influence of the fire. When she adds more cold water she still leaves the kettle-bottom in a position to receive more heat, but as she has added water that is capable of absorbing considerable heat before the kettle again boils, she gains time by the operation, and has a larger supply of hot water on hand. Or, in the case of adding water, she may, when she finds the kettle boiling, should it be full, draw half of it off, and fill it up with cold water, in either of which cases she gains time and warms more water.

In many respects the range-boiler is similar to the water-kettle, and in others it differs from it. One point of similarity is that both are reservoirs; another is, the kettle receives heat through its bottom by the freest of circulations, while the boiler receives its heat through the "water-back" by a circulation which is more or less good, according to the skill and knowledge with which the connections are made.

Figure 114.

The most striking point of difference is that when the kettle boils the cook can take it off the fire, but with the range-boiler it is beyond her power to prevent its receiving more heat short of putting out the fire, and there is nothing left for her to do but to run hot water in the sink until enough cold water passes into the boiler to reduce the temperatures all around, and which may perhaps carry her to a time - after dinner, for instance - when the fire will be poor, and she will not have to attend to it. But it will be said that such a state of affairs is not the rule with kitchen-boilers, which is very true; but the reason it is not the rule is, that most kitchen or range boilers have surface enough on their outside to counteract the warming and heating effect of the water-back long before the water reaches a point to make steam. Or if they have not cooling surface enough on the outside of the boiler, they have long circulating-pipes which carry warm water to distant parts of the house and return it again, every square inch of which is efficient heat-dissipating or giving-off surface, which is continually counteracting the efforts of a smaller but more intense heat-absorbing surface in the water-back. Rarely do we hear of overheating and rumbling except where there is a defective cooling circulation, or no circulation at all. The Sanitary Engineer pointed out some years ago that properly there were three circulations in connection with a domestic boiler. The first and principal one, which must always exist, is the circulation through the water-back; the second, a local circulation in the boiler itself, due to receiving the primary circulation from the back into the boiler well down, instead of at the top; and a third circulation, which takes place in the distributing-pipes. The first circulation is a heating one only; the second is a mixing and cooling circulation, because as the water moves around within the boiler, fresh particles of it are brought against the outside, where it loses its heat; and the third one, when it exists, is always a cooling circulation.

The influence of the second circulation in a cool kitchen with an ordinary-sized back is generally sufficient to keep the temperatures under control, but in restaurants and other warm places, with strong fires and no third circulation, nothing but a very large reservoir (boiler) will do, as by that means a greater quantity of water has to be warmed in the first place, and larger cooling surface is maintained for the secondary circulation to act on.

In your case, in addition to having too much back for the boiler, or too little boiler for the back, whereby you get the water up to the point of making steam, you have nothing like an air-chamber to receive the force of the shocks caused by the concussions which follow drawing water when steam is evolved When you draw hot water, cold water passes into the boiler, and a succession of short quick blows evidently follows. The act of drawing water lessens the pressure, and the water in the boiler, which is already at the boiling point, gives off steam suddenly. It is this steam which makes the water-hammering when being condensed as it meets the colder water.

The violent and sudden changes of temperature also assist in the d'sintegration and stretching of the lead pipes. The trap in the water-back is something we do not like, as its tendency is to retard this circulation, but in your case you evidently do not want to increase the primary circulation, and unless it is necessary to alter the coil for some other purposes it will do.

Hard-metal pipes (brass or iron) will resist the stretching from difference of temperature and pressure better than the lead, and a larger boiler may overcome the other troubles, such as noise, etc.

The rumbling caused when cold water is drawn is also due to the lessening of pressure whereby the steam passes into the cold-water pipe at the head of the boiler through the small hole in the inner pipe. Condensation follows, and a succession of small shocks are felt.