The Golden State: Where & How to Live, Secure, Visit, Enjoy and Thrive in California

First Aid For The Ailing Houses

There should not be more than one opening into a flue. When two heat sources are connected to one flue, each will interfere with the draft of the other.

Following are conditions that will interfere with a free chimney draft and so prevent the proper operation of the fire:
1. Obstructions in the chimney.
2. A projection into the chimney, as, for instance, a masonry projection or the end of a beam supported on the chimney structure.
3. A break in the chimney lining, or a defect in the masonry that permits the leakage of air.
4. Projection of the smoke pipe part way across the flue.
5. An air leak around the cleanout door at the base.
6. The smoke pipe entering the chimney on a down slant.
7. Two or more pipe openings into one flue.
8. Size of the flue contracted at the top, or a small-size pipe extension.
9. Top of the chimney below the high point of the roof, or blanketed by a nearby tall tree or building.
10. Flue clogged with soot or dust, especially at a point where it makes a bend.
A straight flue can be examined from the cleanout door at the bottom or through the smoke-pipe opening by using a small mirror that is inserted into the flue at such an angle that the length of the flue will be reflected. A flashlight can be used with advantage.

A chimney flue should be kept clean, the frequency of cleaning depending on the sootiness of the fuel that is used. To clean a flue, a burlap bag is stuffed with excelsior and weighted with two or three bricks. This is tied to one end of a rope and is lowered down the flue, carried by the weight of the bricks. A tire chain can also be used, swung gently in a circular motion.

A chimney can be tested for tightness by making a smoke test. A fire is built, and when it is burning briskly, a square yard or so of tar paper is placed on it. When the smoke from this appears, the flue opening is covered with a board or piece of wet carpet. The smoke in the flue will then seek another outlet and will disclose any leaks that may be in the masonry. A fire-clay or stainless-steel flue lining is a protection to the the masonry of the chimney and a safeguard against fire. Without a flue lining, the mortar in the masonry may eventually deteriorate and fall out. The openings thus made not only will allow air to leak into the chimney but may permit the escape of glowing soot particles and highly heated gases. The masonry of a chimney should be watched to note whether this condition is taking place. When the masonry becomes loose and can be displaced by jabbing with a screwdriver or ice pick, the chimney should be taken down to a point at which hard mortar is found, and rebuilt. Not to take this precaution is to invite a fire risk.