Poor Cleaning in a KA 18, or any KA DW for that matter
KA DWs while great over built machines were always plagued with complaints about poor cleaning performance, this was by far the MOST Frequent service request for KA DWs we used to get, [ its just not cleaning well ].
KAs because of their extra complexity, clogged filter problems, lower wash arm and support problems and detergent dispensers that did not always work correctly and then you add in the silly dual inlet valve that failed twice as often as WPs, GEs, D&Ms and about everyone else.
The great thing about KA DWs was that they were usually pretty easy to fix, [ one older repairman that Jeff and I knew said he always liked to start of his service day with a good KA DW repair call ]. So as a result we not only made a lot of money fixing KAs but people tended to keep fixing them because they had paid a premium for them and they worked really well when everything was in top condition.
In my service experience too low an incoming water temperature in way down on the list of things that cause poor cleaning outcomes. Purging the hot water lines before starting a DW [ especially on newer machines that boost heat their water and have very long cycle times ] does very little good and the hot water in the lines almost completely cools anyway before the DW fills again for its later fills as many machines now run over two hours. In the days when people actually kept their water temperatures in the 140-160 range DWs only LASTED 6-10 years on average. If you have any DW that you care about water temperatures exceeding 140 [ and 120 for anything built in the last twenty years or so ] will greatly shorten every part of the DW that water touches and your dishes themselves, LOL.