[OrvD]

Our DW has two spots where the cycle dial freezes and requires manual advancing... one is in the wash cycle and one in the rinse cycle. From comments on other Bosch DW's I suspect it is from a problem in the built in water htr system. For this model, is there a likely cause other than the htr itself? Are there any easily accessible parts that can be checked without full removal of the DW, etc.

[Gene]

The heater & NTC can be accessed or measured from the right side of the dishwasher, but can only be removed by dropping the entire base (by flipping the dishwasher on its back) since they are wedged underneath the tank.

Gene.

[OrvD]

Thanks Gene... I'm a novice at this... how do I test the htr and NTC? At at the points where the dial stops I opened the door and the water is only warm, rather than the very hot that it used to be. Does this narrow down the likely problem?
I assume the right side is when looking at the machine from the front. Is there a good illustration available to show these items?
OrvD

[Gene]

The heater resistance can only be measured at the heater terminals.
It suppose to be about 11 Ohms.


The NTC and High limit are contained in the same part.


The NTC resistance should be about 55 kOhms at the room temperature.


To check the water flow switch, remove flow switch micro switch, close its contacts and measure its resistance. It suppose to be 0.4 Ohms.

- The part number for the heater assembly is AP2804286

- The part number for the NTC is AP2804285

- The part number for the flow switch is AP2802178

- Here are the break down diagrams for the Bosch dishwasher Model SHU4002 UC/06


Gene.

[OrvD]

Gene... I finally got my Bosch dishwasher out and the bottom off... that was the toughest part.

The heater assembly measures 11 to 12 ohms (my tester is a lower cost digital model)... which meets the 11 ohm requirement.

The Flow Switch has 3 contacts... C1 (grey/blk), No. 4 Red (goes direct to heating element) and No. 2 (white)
With switch button depressed (closed) ...
C1 to No. 4 shows .3 ohm
C1 to No. 2 shows no resistance (shows .3 when open)
No. 2 to No. 4 shows no change (stays at 1. closed or open)
Allowing for meter error, this is close to the required 0.4 ohms, so I judge that part to be okay.

The NTC shows 1.0 at room temperature... vs the required 55 ohms... so I will order and replace that part first. (Will also order the Flow Switch just in case.)

Am I on track? Any further tips at this point?

Very much appreciate your expert help.

Orv D

[Gene]

Replace the NTC and keep me posted.

Happy New year.

Gene.

[OrvD]

Gene... the parts arrived (NTC and Flowswitch) and I replaced both of them. However, my Bosch Dishwasher problem persists.
The dial sticks at about 5 o'clock (wash cycle) and 9 o'clock (rinse cycle). It proceeds when I advance the dial about a 1/4 inch.
I note the water does not reach a hot temperature (it is about the incoming water temperature), so I still suspect the problem is in getting power to the element (the element tests about 11 ohms).
Is it possible there is a contact open at the dial or somewhere else that is the culprit? Is there a wiring diagram that I should use to trace the connections?
Thanks... I want to keep at this til it's solved.
OrvD

[kawfeeman]

just out of curiousity, how many buttons are on control panel ? have you tried a different program ?

[OrvD]

Thanks for the quick response.

There are four buttons ... Power Scrub, Regular, Delicate and Rinse/Hold.

I did try Rinse/Hold, with the same reult. However, I will run it on Delicate and see if that results in any change.

OrvD

[kawfeeman]

the rinse / hold program does not heat water .. should only be a 9-11 rinse program ... if timer is hanging up in rinse/hold then you have a bad timer ... different TStat's are engaged with different programs .. ( regular should be @ 45 - 48 def C and Power Scrub should be about 60 deg C.... does timer hang up on Power Scrub also ?