Bosch dishwasher SHX3AM05UC/01 poor/inconsistent performance
Posted 24 September 2010 - 11:08 AM
Usually (but not always) the lower rack's contents get clean; sometimes the upper rack's contents mostly do not get clean, and occasionally the lower rack's contents don't get clean. I suspect but cannot verify that the upper wash arm, which on this model is on the underside of the upper rack, is not always spinning. I've disassembled and inspected the upper wash arm and its feed pipe assembly. The O-rings are good, there's no trash in the pipe or arm, and the arm spins freely by hand. And when I open the dishwasher in the middle of a wash cycle, there is water flowing out of the holes in the upper wash arm. But this dishwasher just isn't working very well despite being well under two years old. Suggestions please!
Thanks in advance.
Posted 24 September 2010 - 11:19 AM
make sure the water fill level comes up to the top of the coarse filter-- it's a timed fill on these Ascentas, not a level-sensing fill like on the higher end Boschs.
Take the sump filters out and scrub 'em real good-like-- even partially-occluded filter holes can starve the pump and make poor washing
Also, been getting lotsa washability complaints since they removed phosphates in July. More...
PMed you the service manual.
Let us know whatcha find.
Posted 24 September 2010 - 11:41 AM
I've just started a regular cycle and the water reaches at least 1/4" above the top of the big rectangular filter screen. It does not cover the upper rim of the round coarse filter, should it?
I pushed both wash arms to the same rotative position, closed the door, allowed the cycle to start, listened for water being sprayed inside the dishwasher, let it spray for a few seconds, then opened the door and found both wash arms exactly where I'd put them. I repeated this a few times with the same results. It appears neither wash arm is spinning.
Thanks for the service manual. It says fault code diagnostics can be accessed by pressing and holding the < and > buttons, then turning the dishwasher on, watching for the regular wash light to flash and the quick wash light to burn steadily, then pressing >. However, this does not work. I have repeatedly tried holding < and > then turning the dishwasher on, and nothing happens -- it is as if I have just turned the dishwasher on without pressing or holding < and >.
And another update: I let the dishwasher fill with water, then I poured in more hot water to above the level of the rim of the round coarse filter, then I let the dishwasher start. Even with the extra water, the wash arms do not spin.
Meeeeyeahhhhhhh…now what, doc? (CRUNCH crunch crunch crunch)
Posted 26 September 2010 - 09:07 PM
So okeh, I pulled the unit out, turned it on its front, and removed the pump/heater/motor assembly, expecting to find the pump clogged. That expectation was dashed, however; the pump is internally pristine; the impeller is in perfect condition and spins freely. I shone a powerful light in the transfer ports (one of which leads to the lower wash arm, and the other to the upper) and found no clog there, either. No evidence of any detritus in any of the helpfully-translucent drain hoses, either.
Now, this what I describe raises an interesting quandary: there is strong language in the warranty stating that any unauthorized service work, including exploration or "fixing" (quotes theirs, not mine) by the owner, nullifies the warranty. So…don't ask, don't tell, right? Wrong; the pump is built with tamper-telltales: it is held together by four tapered tabs, each of which fits into a slot and snaps into position on a rearward-facing ledge. To take the pump apart, you press on the tapered end of the tab to unhook it from the ledge. Behind each tab is a second tab, stressed to just shy of the breaking point. You so much as TOUCH the tapered tab and the indicator tab breaks off. It does not interfere with reassembly, but it does indicate "someone's been here". Oh yeah, and there's one of those hellspawned single-use crimped hose clamps holding the pump output to the water transfer port boot. So now I face the interesting choice of how to approach a conversation with the fine people at Bosch. Do I play dumb, or do I lay it on the line for them? And will they say "Eff you" or will they step up? Stay tuned.
Per our Zen Master's request, I took photos of the pump removal and take-apart. Follow along with me as we remove and disassemble the heated circulation pump.
When you hear this sound »Doink!« y'turn the page. Ready? Let's begin.
Here's what we see when we remove the dishwasher and tip it forward onto its front:
The pump is held to the underside of the dishwasher with a rubber strap to isolate noise and vibration:
Prise the strap off the pump's hanger tab:
And use a T20 Torx™ driver to remove three of the four screws that hold the pump outlet boot to the water transfer ports:
…at which point you'll discover that with the pump still in place, the fourth screw is inaccessible by any Torx driver on this plane of existence. So, prise open the hell-spawned one-use-only Keystone Klamp that holds the boot to the pump outlet:
…and firmly pull the pump's inlet boot off the sump outlet:
Now you can rotate the pump and see the electrical connectors. There appears to be one 7-pole disconnect on the side of the pump:
…but it's really a 3-pole and a 4-pole. Go ahead and unplug them with wanton abandon—the plugs and sockets are keyed so they can be installed only the right way round and on the correct pins; you cannot swap their positions. This is an example of poka-yoke, mistake-proof design:
Next, turn your attention to the 3-pole motor connector at the end of the assembly. The end shield is easily removed by undoing two T20 Torx™ screws:
With the shield removed, the 3-pole disconnect can easily be unplugged:
CONTINUED BELOW . . . .
split into another post, limit on number of picture links
Edited by RegUS_PatOff, 31 May 2013 - 02:32 PM.
split into another post, limit on number of picture links
- PDuff likes this
Posted 27 September 2010 - 05:45 AM
Posted 30 May 2013 - 09:48 PM
CONTINUED FROM slantsixdan
split into this post, limit on number of picture links
Squeeze the tapered tabs that hold the pump housing to the motor housing. As you do so, the tamper-evident tangs (indicated by green arrows) will snap off. Use a screwdriver to lever under the overhang of the housing half and prise the two halves apart:
Now separate the two halves and you can inspect the impeller and volute for damage or obstruction:
Reassembly and installation is the reverse of removal and disassembly, except that you'll be substituting a reüsable hose clamp for the hell-spawned single-use variety. Lubricate the pump housing seal so the metal cylinder easily fits back into its groove.
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