Plumbing 



225 



wall and tap the house drain. This connection is protected by a trap, a precaution 

 which should always be taken in like cases where the house drain is thus entered. 



The waste from the refrigerator should not enter the house drain, as it adds 

 one more possible source of trouble, and is not at all necessary, as the water 

 discharged is harmless. It should empty into the cellar sink, and may be con- 

 nected with the overflow pipe from the attic tank if convenient. 



The system which avoids the use of the back vent and relies on the non- 

 syphoning trap as a protection, is shown in Fig. 34. As the ordinary country 

 house may connect with a cesspool, usually located at the back of the house, 



Fig. 42. Section showing the installation of the back-vent system 



A. Soil line D. Branch water pipes 



B. Main waste E. Branch vent 



C. Main vent F. Rainwater leader 



G. Removable tap screws 

 H. Cap 

 I. Fresh air inlet 



J. House trap 

 K. House sewer 

 L. House drain 



M. Branch soil 

 N. Screw cap 

 F. Area drains 



T. Mouth of house drain 

 V. Water seal 

 W. Branch soil pipe 



