Just had a plumber install a flush mounted supply/drain box in the wall
between studs. He said the 28 inch height of the top of the standpipe would
not be a problem re siphoning. Now, before sheetrocking, I looked at my
Kenmore manual and it said Minimum height for top of standpipe should be 39
inches! This worries me. As a test, I filled the washer tub to "large load"
level, but no siphoning occurred. Should I have the box raised the 11 inches
anyway, just for safety, or should I buy Kenmore's siphon-breaker attachment
for floor drains , and leave the plumber alone?