1. Is it code to drain a dishwasher just like a washing machine with a standpipe? My dishwasher will be locate in the end of a peninsula about 8 feet from the kitchen sink.
As long as it has a air gap and the standpipe is high enough so it will not overflow if the sink drain backsup into it.
2. Can the condensation drain from a 2nd floor furnace drain to the stand pipe of the washing machine? I have no wash tub.
That is one possible place where it should go.
3. Is it possible to tie a crawlspace furnace condensation drain into the plumbing system? Is there something made specifically for this?
No. And No. If you do it your next posting to here will be, "why do I have sewer gas odor all through my house?"
Thanks in advance