You may be over-thinking this. I have the same set up as you (DW two cabs over from sink) and used the drain extension as you mentioned.

I just ran it and the water supply hose behind the two cabinets between the sink and the DW. I tied in the extended drain hose to my garbage disposer as normal.

No muss no fuss and it works fine.

Good luck
Doc

I probably am over-thinking it ... happens more often than not.

Thanks for the response, while I can't go through the cabs (they face opposite directions so that the back of one cab is the front of the other), I should be able to go under them, as recommended in the plumbing version of this thread.

When I talked with Miele Tech Support, they said a high loop is not needed.

I understand that the unit has a built in check valve, but that seems really strange and contrary to what I thought should happen.

I am contacting them via email and going to ask them whether a high loop is:

(a) optional (no preference either way and whose presence doesn't negatively affect the installation)
(b) required (must be present)
(c) excluded (must not be present)

as I would like to get their response in writing instead of verbally. I'll post what they respond with when I get an answer.

Local codes are what you need to concern yourself with as far as installation requirements. They will trump any manufacturer's requirements if they are more restrictive. Whichever more restrictive requirement is in existance, that's what has to happen.

But I would really question any installation like you are describing from a functional standpoint. DW's should be always be located as close to the sink as can be managed. And if you are changing things like you say, you are changing them for the worse, NOT for the better. Time to post your kitchen layout for feedback.

"they said a high loop is not needed. "

This is correct. High loop isn't a bad idea though, and should be done at the sink in this instance.

"but that seems really strange and contrary to what I thought should happen. "

So it's strange, so what ? It one of the things that makes Mieles cost more.

Best solution would be to have your home's drain system extended to the new location.

live_wire_oak:

The DW will be installed to local codes. The issue came up because I had asked Miele tech support to comment on whether the high loop should go behind the DW or at the sink. They said that a high loop was unnecessary. That answer was unexpected, which is why I am posting about it here. I submitted the question via email to get a response in writing instead of verbally.

As far as the placement goes, I'll copy what I posted in the plumbing section:

We originally were concerned about the placement, but realized it was a non-issue after living with a mockup for four months. Because this is part of a peninsula, even though it is moving two cabinets away, it is effectively only one cabinet away and still within the National Kitchen & Bath Association planning guidelines for dishwasher placement (Locate nearest edge of the primary dishwasher within 36" of the nearest edge of a cleanup/prep sink.).

Furthermore, where one would stand when unloading puts virtually no additional path for water to drip beyond where it would when the unit was next to the sink. There is ZERO additional floor exposure for drips and about 2 sq ft additional countertop exposure ... a countertop that would have been wiped down anyway after doing dishes.

You are over thinking this.

Put the DW where it works for you.

Use a high loop or don't, it won't make a difference with that DW.

The rest is just causing you to lose sleep.

I recall my Miele DW being installed first time around with no high loop: it has a non return valve in the exit line. When I remodelled and reinstalled it the plumber did place that valve in a "high" position, but had it upside down. I managed to convince him it had to be corrected. As far as I recall the manual on my DW specifcally orders the non return valve to be placed a certain way up for it to function. Obviously you will want to check your manual and monitor the install closely for this. Good luck!

There is no "placing" the non-return valve, it's buried inside the machine where you cannot see it without removing parts.

You are probably thinking about the anti - leak system which had a solenoid at the water intake connector on prior generations. That needed to be oriented in a certain manner in order function properly. The current models do not have that visible anymore.