I have a new GE dishwasher (4 mo. Old) and it fails to drain completely leaving about a half inch of water in the bottom after the dry cycle is completed. On investigation I noted that the installer hooked up the supply to cold water. I'll change that over to hot right away but I suspect the drain problem is independent. Is there something I can check first before I call the serviceman?

David

Questions:
1. Was an air gap installed?
FaucetDepot.com - Delta 72020-SS Classic Dishwasher Air Gap Brilliance Stainless

2. Does the dishwasher drain go way overhead before it enters the trap?

1 or 2 must happen.

3. Garbage disposal?