SYSTEMS OF HEATING 



111 



Steam heating 



Hot-water heating 



High-pressure systems: 



(1) Gravity-circulation with return-trap or 



pump. 



(2) Fan, or forced-blast system. 



Open system: 



Direct or indirect. 



Closed system. 



Direct or indirect. 

 The above topics are to be assigned for investigation by the class. 



QUESTIONS 



1. What makes a fireplace smoke? 



2. Why will a piece of burning paper held up the 

 chimney often stop the smoking? 



3. Why will open windows make the chimney 

 " draw " better? 



4. Why are chimneys often covered with a stone 

 flag, and openings left in two parallel sides in the 

 chimney? 



5. What sides of the chimney should be left open? 



6. Why do we have land breezes at night, and sea 

 breezes during the day? 



7. Why is there usually a " calm " about sunset? 



8. Why is it frequently difficult to warm a room 

 on the north side of a house by a hot-air system? 



9. What is observed rising over a radiator? Why 

 does it rise? 



10. Why not have a chimney on the outside of a 

 house? 



11. Which would be better for ventilation, a fire- 

 place on the opposite side of the room from the 

 windows or on the same side? Why? 



12. Draw a diagram illustrating currents of air? 



13. At what time of the year may a room be most quickly aired 

 out? Why? 



FIG. 88. 

 Why is it 

 possible to 

 heat the 

 water in 

 the tank? 

 Where will 

 the hottest 

 water be 

 found in 

 the tank? 

 Why? 



