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Saturday, November 19, 2011

Bosch/Gaggenau/Neff/Siemens/Thermador/...runs continuously and displays "1"

**Please disconnect the power or turn off the breaker before attempting any service to the dishwasher.**

Let me start with a disclaimer. While I've been a journeyman ticketed technician since 1997 and repairing appliances professionally for nearly 20 years, (factory trained on many I service) I am not a professional writer nor am I a guru web designer, so what you see is what you get...I hope it will suffice.

I also do not represent Bosch or any of it's subsidiary companies in any manner, this is simply a "do-it-yourself" repair blog as it pertains to Bosch built dishwashers. This blog will address specific issues associated with heating errors, commonly displayed as the number 1 in those dishwashers which have a digital display, those without a display will usually (but not always...depending on make and model of course) be displayed in the "Delicate/Econo" LED on the buttons being lit to indicate a fault.

The other important factor to mention here is the "1" being displayed can manifest due to several faults...never assume or allow anyone to imply one specific part being replaced will remedy this error...the actual fault must be determined first.

As I mentioned there are several possible faults that will manifest with the "1" being displayed, I will mention those possibilities, though I will only address the control issue here on this blog...focusing on what I've found most common, thus most likely. (If you've diagnosed and ruled this possibility out already, this is the time to abort and contact me for further more detailed and specific assistance).

**Be sure you are familiar with it's "normal" performance before declaring anything is indeed at fault or calling in an over the owners manual thoroughly** 

I've performed numerous repairs on these dishwashers, including control replacements or arriving after another technician had replaced the board and found the issue was simply lack of knowledge of how these are supposed to work. 

When a control is installed brand new, it is likely going to display a 2H or 99, THIS IS NORMAL(note the upper case H, not lower case h...the 2h is for delay) this is telling you the approximate time the last cycle took to complete (it is not an actual time but rather an estimate). In the case of the 2H, the cycle exceeded two hours. It is also the default display, after replacing a control and running a complete cycle, the control will adapt to your set-up, i.e. water inlet temperature, drain etc. Ideal inlet temperature is 120 degrees Fahrenheit.

I had a recent experience where I was called in to address the 2H being displayed in a new control which had been replaced by a large retail store serviceman and they could not explain to the customer why it still displayed 2H as it did prior to the new control, thus the technician ordered another control assuming it too was faulty. Needless to say, this left (understandably) the home owner/customer not satisfied the dishwasher was going to be repaired properly. In the end, I made sure it was.

I digress,

By far the most common failure with the Bosch built dishwashers have been the control board, or more specifically the cold solder joint for the heater relay on the control board. In fact, this is where you as a consumer should check your model number and serial number...the serial number is also referred to as a "batch" number which identifies when (the date) the unit was built.

BSH Home Appliance Corp. issued a recall on several of the models they build (primarily to Bosch & Siemens units manufactured and sold between 1999-2005) and if it applies to your machine, stop ! Call Bosch or check out the link to the websites provided to see if this is applicable to your model of dishwasher.

**In the event you have a Gaggenau, Neff or Thermador, I'd recommend checking with their customer service people to be sure**

The appliance details can be found either engraved on the top or on a sticker on the left hand or right hand side of the inner part of the door (see pictures below).
To identify if you are the owner of one of the affected dishwashers, please do the following:

1. Go to your dishwasher and get your model details and batch number.
2. Check whether your batch number range lies within FD 7901 to FD 8504 – if not, you are not affected by this safety notice.
Now to address the most common heating faults with these machines (the solder failure issue) should your machine not be part of the recall.

My Opinion - if you or someone you know is proficient at soldering, a lot of times it can be remedied by simply repairing the solder…(provided the circuit board/pathways are not damaged too bad) but it has to be done well or it will not last, (Bosch recommends replacing the control and I don`t pretend to speak on their behalf nor do I profess to know better). This is just my experience (it work`s) and my opinion (why buy new if one can safely repair ?)

As I've alluded to the issue is likely within the electronic timer/control, specifically the heater relay solder joint. Now to mention the other culprits, a faulty flow switch, NTC (negative temperature coefficient type hi-limit thermostat) or heater/element can also cause this, but not very probable.

If you feel capable of checking this on your own, there`s a way to visually inspect the control yourself...with my instructions, it really isn't very complicated.

circuit board.  The images I've provided are typical of the "SHU" series dishwashers, but these guidelines and the principles of the inspection/repair, apply to all the BSH machines.

The culprit will 99% of the times will be one of the pins from the heater relay,

**Flip this over and inspect the solder joints, it will be obvious when you see it.**

...hence the unit sit`s and takes longer & longer to finish because it can`t heat to advance. (unless interrupted via depressing the 2 buttons for "cancel"). This can also manifest in the scenario where the cycle takes a long time as I mentioned and eventually displays "1" on units with a display….as a by-product  it usually results in very poor cleaning as well.

You can also diagnose or dismiss a heating error if you have access to, or own an ammeter/multi-meter...though it must be the "clamp-on" type shown.

**I do not recommend this for novice do-it-yourselfers...This also requires the electrical supply to be on, it's advice-able to have some knowledge of electrical circuits or electrical theory, please use caution.**

I suggest you clamp onto the black wire, aka "line one" (L1) at the junction box, then turn the power on.

...then start the unit through a regular or eco-wash cycle (any cycle with the exception of rinse & hold or cancel) the black wire should draw approximately 11 amps on the meter during the wash cycle...after it fills and the flow switch indicates it has adequate water to engage the heater.

**these units incorporate what's known as an "instantaneous heater assembly", meaning the water heats as it circulates through the element housing, (flow through heater) hence, if the either the water inlet valve fails to allow water to flow into the unit or the circulation motor fails, the element will not be energized**

Since I am a technician the image below shows the method I prefer, thus allowing me to visually inspect wiring etc. with the door panel removed placing the ammeter on the gray w/black tracer wire to the control.

If you do not feel comfortable attempting this service, call a local pro, preferably one familiar with Bosch/Gaggenau/Neff/Siemens/Thermador, to service your machine. I have link to the top right of the page for my paid services where I can provide detailed and specific support to your needs, click on "Buy Now" to utilize this service. I too am a factory trained BSH Home Appliance Corp. technician.

NOTE: when replacing boards…

Thanks for visiting my fixedappliance blog today. I hope I was able to provide you with some useful information to keep your hard earned money in your pocket and the steps to do-it-yourself. Good luck.

Please feel free to leave feedback or ask further question if anything is not clear or the procedures above do not resolve your particular problem.

**I realize do-it-yourself is not for everyone, (I sometimes wish others realized this before attempting as well, but oh well) If you have any hesitation to perform anything suggested here, please contact a professional or click the button to the top right of the page for my paid services, click on "Buy Now" to utilize this service.**

I welcome your involvement, but please respect this blog solution/diagnoses is only the first and most common, not necessarily the resolve for all...but rather most heating error codes as they relate to these BSH dishwashers. Please contact me if you believe I may be able to assist you in this matter or any other manner.


Mark M.

1 comment:

  1. Hey! I had this problem on my Thermador DW44ZS / 21 (circa 2005) and found my control board to be fried. Had to be replaced ($300) but all is back together. The part number is 496013 - this will be helpful to anyone else with this issue. Saved me some serious bucks - thanks!