Jeff Wisnia wrote:

Speedy Jim wrote:


If you are certain there is no vent, you could use one of those
expansion plugs that attach to a garden hose to flush the drain
under pressure. This can be effective in some cases. Do NOT
try it if there is a vent; you may flood the kitchen.

Jim


Am I correct in assuming that the flood you refer to occurs when you
take out the expansion plug without realizing that you've just pushed
water up into and filled the ventpipe all the way to its tippy top?

Jeff

Yes indeedy! What a surprise it makes!
Jim