dishwasher drain height

[kitchenredo]

The installation manual with my new dishwasher says that the connection to the sink drain must be a minimum of 18 inches above the floor. So, the drain line goes up a minimum of 32" and then drops down to the tee connection at the sink drain. Can anyone explain to me why the 18" minimum above the floor? Seems to me, the lower the better as long as it is above the trap.

Thanks.

 

[stevemachine]

To exceed flood level rim of the dishwasher so that it doesn't drain itself during the cycle. Not saying its exactly 18" but that's usually why you need a d/w loop as well. At least that's all I can think of.

 

[kitchenredo]

Still trying to understand this. I thought that the loop or air gap kept the system from draining during wash cycle.

 

[stevemachine]

Yeah that's right. I can't think of any other reason as to why they would suggest 18" off the floor for the tie in though. Call the manufacturer and ask them maybe

 

[IFIXH20]

The 18'' -- 32'' above the floor is for a serval reasons -- to stop the tub from siphoning , to help prevent water form backflowing into d/w drain , to help keep proper back pressure on the pump for proper draining . Although dishwasher drain loops on the side of the dishwasher, you still need the 18'' -- 32'' for proper drain operation.

 

[johnjh2o]

Even though the line loops if it is connected below the 18" it could siphon the dishwasher.

John