Diplomat 8242 not heating water – where’s the element?

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  • July 17, 2011 at 12:04 pm #63974
    wallynyc
    Participant

    Hi,

    I have a Diplomat 8242 that I inherited in the house I bought 3 years ago. Upon first using it back then, it would generate a loud crack when switched on. I found the mains filter to be damaged (plastic case was split open) and replaced it. Since then, 3 years of use with no problem. Until….

    Recently, the dishes were still wet and there was no steam when opening the door. Also, the cycle appeared to become longer and longer. Then I get the error codes of (left-to-right) LEDs 1 & 2 flashing and 5 on. This error code isn’t in the user manual. I’ve tried resetting the PCB and this clears the fault display but doesn’t help for the actual problem of no heat. So after researching the matter, the common issue seems to be a faulty heater element and it appears simple enough to fix. However, I can’t find such an element 😯

    There is no element as described in the forums here (or shown here:http://www.espares.co.uk/part/dishwashers/diplomat/adp8242/p/1083/976/0/539191/970022/2100-watt-dishwasher-heat.html) but instead I found what looks like a cylindrical heating element mounted on the input side of the water motor. But it is impossible to get to, as the connections are on the top of the cylindrical element, right out of the way for fingers to get in there. And the side which is mounted to the pump seems to be fitted with high-pressure fixing rings instead of the usual clamp-type rings, so I’m not going to try and get that off just yet.

    I suppose my question is – has anyone come across a similar model which uses this strange heating element and if so, how best to test if the element is OK while in situ (using a DVM or similar continuity tester)
    Also, how easy is it to remove the faulty heating assembly and what is the part code/number for a replacement – I can’t seem to find this anywhere on any forum or spares supplier’s web-sites.

    Strange!

    Thanks in advance,
    David

    July 18, 2011 at 9:26 am #355696
    electrofix
    Moderator

    Re: Diplomat 8242 not heating water – where’s the element?

    heating element not strange in fact very common

    unplug dishwasher. pull it out and take side off to access

    could be heater or pcb ( may be a bad solder joint on board )

    test heater with multimeter on ohms scale you will get under 100 ohms if ok

    Dave

    July 22, 2011 at 9:20 pm #355697
    wallynyc
    Participant

    Re: Diplomat 8242 not heating water – where’s the element?

    Thanks for the pointers Dave – I’m assuming 100 Ohms or less indicates the element is OK when the meter is applied across the element terminals when the 2 wires connecting to it are disconnected (element out of circuit)?

    Now I feel slightly ridiculous. I’d taken it for granted that it was an ADP 8242 model – from the user manual that was left with it. After all, everything in the user manual matched what I saw within the dishwasher. Further investigation revealed it is in actual fact an ADP 8902 model….. 😳
    So the fact I couldn’t find anything in my machine that resembled the heating elements displayed on various online spares supplier web-sites for the 8242 model makes sense now. I was looking at the wrong machine type. Idiot 😡

    So I now know that the cylindrical ‘part’ which forms part of the water feed to the input side to the motor is in fact the heating element. At least I can now ask questions which actually refer to my dishwasher model.

    I’m more than comfortable with electricals, electonics, DVMs, soldering/desoldering & component replacement. My specific question would be;

    On the ADP 8902, the heating element connects to the electrical system of the unit with 2 wires, a brown and a blue. The brown (I assume is +v DC) appears to connect straight to the control PCB and the blue (I assume 0v or -ve DC) connects to the airflow (?) sensor switch – the round thing with an airflow tube between it and the sump. This airflow switch must then have to be in a non-fault-state in order to pass the current through it and complete the DC current loop (to 0v DC at this point or ‘through’ the next sensor, etc., and eventually to 0v)

    So 2 conditions must be met in order for current to flow through the heating element (1) The brown wire must have voltage applied by the control PCB at a certain point in any wash cycle and (2) the airflow sensor – and any further downstream sensors must not be in a fault state.

    To help me to diagnose the fault area, what is the DC voltage applied to the brown wire from the PCB when it activated the heating element? This will give me a clue as to what to look for at the various stages of the wiring.

    And does anyone have a wiring diagram for a ADP 8902?

    Thank you,
    David

    July 23, 2011 at 8:51 am #355698
    electrofix
    Moderator

    Re: Diplomat 8242 not heating water – where’s the element?

    The brown (I assume is +v DC) appears to connect straight to the control PCB and the blue (I assume 0v or -ve DC) connects to the airflow (?) sensor switch – the round thing with an airflow tube between it and the sump. This airflow switch must then have to be in a non-fault-state in order to pass the current through it and complete the DC current loop (to 0v DC at this point or ‘through’ the next sensor, etc., and eventually to 0v)


    forget DC its all AC and at 230v
    heater will be 230v approx 1.5 kw
    airflow switch is a pressure switch that uses air built up in a pressure chamber by the weight of water or in some cases ( not sure about this model ) by the pressure of water from the wash pump ie no water no heater

    there will be a relay on the pcb that has to operate to power the heater and there may be overheat stats to protect against fire should the heater come on without water. also look for breaks in the wiring loom at the bottom of the door where the wire bend as the door opens. common fault on some dishwashers

    hope this helps
    cant be more specific as i dont know model and have no tech info

    Dave

    August 4, 2011 at 4:27 pm #355699
    wallynyc
    Participant

    Re: Diplomat 8242 not heating water – where’s the element?

    Thanks to all for the tips & advice about the heating problem I had.

    I fixed it – and it was less trouble then I thought. Found on the solder side of the PCB that one of the relay output pins (on the side of the relay which switches the heating element on) had a very badly soldered connection – almost completely dry of solder. Buzzing out the connection between this pin and the heating element showed a completely open circuit. So after re-soldering it, continuity was restored. Fired up a normal wash cycle and it worked fine. I now have a fully working dishwasher again 😀

    Thanks again & I hope this fix information helps someone.

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