HI, water not heating, local engineer says no feed from PCB, He can replace but thinks it will need reprogramming which means a Bosch AGent, is this likely?, the cost of this will write off the machine, I'm thinking of removing relays to test , are they availiable? will reprogramming still be needed?. THe machine is hardly used, heater tests ok,20 ohms.PCB looks clean no bad joints.
NEff Dishwasher S4456S4GB/35
- Thread starter nortonbob
- Start date
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Programming...no. Model coding...yes.
Many Bosch/Neff diswasher pcb's need to be coded to particular model variants, but they always come with a configuration guide (albeit a poor English translation of one). You can replace a heater relay if you are handy with a soldering iron. No-heat issues can have several causes, but in this case I would tend to agree with the diagnosis you got. Replacing a defective heater relay doesn't require re-coding.
Many Bosch/Neff diswasher pcb's need to be coded to particular model variants, but they always come with a configuration guide (albeit a poor English translation of one). You can replace a heater relay if you are handy with a soldering iron. No-heat issues can have several causes, but in this case I would tend to agree with the diagnosis you got. Replacing a defective heater relay doesn't require re-coding.
Hi Zipper, Still working on the Dishwasher, The PCB has been off and checked out by QER, but no power to heater still, I would like to test the resistance of the thermostat on top of the heater 20-50 k ?? is it possible to test or get this off without big stripdown ? I have had the machine running with the front panel off (hotwired door switch) but no voltage appears at the pcb/heater plug.I understand that a dud thermostat would do this?.
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Your machine has the dreaded "Instantaneous water heater" & it isn't so nice to work on. On top of it sits a combined NTC/85C safety switch. The safety switch cuts out the element if the water temp goes above 85C. The NTC controls cycle temperature via the pcb . You could check the value of the NTC from the pcb, it would save you struggling to limbo your way in there to remove it. At 25C it should read around 48kohm. If you have to remove it then it is easier to work on if you take out the tub/base screw at the rear RH side & the retaining screw/locking tag at the front RH side. Then lay the machine on its side & separate the base & tub about 3-4cm at the RH side & wedge a piece of wood in there. The combo NTC doesn't fail very often but it can happen.
If your pcb got a clean bill of health then I would check the safety pressure switch on the end of the water heater first. It is activated by pump pressure via a diaphragm during the wash cycle. If there is lack of pressure due to foaming, under-filling, bad circulation motor etc. the switch wont activate & no heating will occur. If you need a better "how to" send me a PM with a valid email & I'll send you a couple of drawings that might help.
If your pcb got a clean bill of health then I would check the safety pressure switch on the end of the water heater first. It is activated by pump pressure via a diaphragm during the wash cycle. If there is lack of pressure due to foaming, under-filling, bad circulation motor etc. the switch wont activate & no heating will occur. If you need a better "how to" send me a PM with a valid email & I'll send you a couple of drawings that might help.
Thanks for the info Zipper, can't see PM adress for you on the site, must be getting more stupid daily!!, How to test resistance of thermostat from pcb plug? would machine need to be Running? I can do that, not running plug reads infinity, pressure switch stopping me ?.
You don't need to run the machine to test an NTC. You should get around 48kohms on a good NTC at room temp. If in doubt remove the combo NTC/safety stat & measure it cold, then submerge the sensor end in a cup of hot water. When warmed to around 65C the NTC resistance should drop fairly quickly to 9 - 10kohm. There should be continuity on the safety stat hot & cold. The NTC body is held in place by two plastic clips. Make sure not to lose the o-ring when removing.
Thanks Zipper, how do i PM you?, I have no problem testing stuff ,just can't see how to get it out without breaking, does the micro switch on the heater lever up and out? are the clips on the ntc on both sides? if so one is behind out of sight? ,the how to information would help possibly.
Check out the link & study pages 51 - 57 http://rakerprivatelibrary.com/Dishwashers/Bosch/BOSCH Dishwasher Repair Man SHI SHU.pdf
Although for US machines models the build is virtually identical to yours component wise. If you google long enough its amazing what you can find on the public domain!!
Although for US machines models the build is virtually identical to yours component wise. If you google long enough its amazing what you can find on the public domain!!
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