Elektroda.com
Elektroda.com
X

Search our partners

Find the latest content on electronic components. Datasheets.com
Elektroda.com

Whirlpool 7440/1 Dishwasher - fuse blows, heater short circuit?

psg 5643 6
This content has been translated flag-pl » flag-en View the original version here.
  • #1
    psg
    Level 14  
    Hello
    The Whirlpool model 7440/1 dishwasher blown the 20A fuse during operation (a separate line for the 16A dishwasher blew out and then the second one on the staircase for the entire apartment). There was a slight stench of rubber. Four years ago I replaced the wash pump. Now, it's probably time for a heater, but before I buy, give me your opinion:

    1. The heater (in the pictures below with the meter), as you can see, has sooty plugs, maybe there was no good transition and the programmer heated the heater too much, hence the fuse in the apartment blown. The meter shows the resistance on the heater plug is OK 25? (range 25-30). There is a transition between, for example, the left pin of the plug through the thermal fuse to the left side of the heater and the same. Resistance on the heater itself (photo 2) also 25? -> conclusion the heater is working, I suppose? If the left or right one-time thermal protection of the heater was to work, its bimetal would remain in the open position, preventing the heater from heating, and here both thermals are short-circuited and there is a transition to the left and right side, of course, without a short circuit in the heater plug itself.



    There is also no transition between the ground pins (yellow and green wires) and the heater plug pin, i.e. heater to ground / housing transition. But maybe I'm wrong and the protection works the other way around (when short-circuited, the thermic remains shorted): when measuring these wires, the heater should not be on the resistance meter, e.g. 25? (i.e. like in the plug) only open = no transition. So both thermal protections should be open?

    But in this situation, where would there be a 25? resistance in the plug, after all, it is connected in series with the left and right side thermals to the heater wire. This thread forced me to consider such considerations: Link . There, someone said that the heater should be replaced because the resistance of the heater is 25.6? on the heater wires

    2. If you suggest a short circuit on the programmer (from the relay side of the HEW heater, then on the programmer plug, the heaters should be more than 25?

    3. If I were to buy a new heater, please if anyone knows what is the part number of such a heater with a new type pump for my 7440/1 dishwasher, as in this photo:
    Whirlpool 7440/1 Dishwasher - fuse blows, heater short circuit? Whirlpool 7440/1 Dishwasher - fuse blows, heater short circuit? Whirlpool 7440/1 Dishwasher - fuse blows, heater short circuit?
  • Helpful post
    #2
    ventil
    Level 11  
    Hello.

    You have a disconnector (fuse) or differential (RCD) because sometimes it's a difference. For me, when the thermic on the heater burned out (because the pumping propeller stopped and the heater overheated), this is a disposable element and the heater had a break after that, so it did not heat at all. Your contact clearly did not touch because it is blackened, but it would not cause the fuse to be disconnected.

    If the heater has resistance it looks good. As you write - there is no short circuit between the housing, unless it has charred so much that for a moment there was a breakdown to the grounded part or between the contacts, which caused a temporary short circuit. If I were you, I would disconnect the heater, and connect a light bulb like 220V, say 100W to these cables that power the heater and start the dishwasher to check if the fuse continues to blow. If it does not break out, the bulb should light up after a while when the dishwasher starts the program.

    We are looking for pumps and heaters for the ADG ADP series dishwasher
    Sample pump: Link
    Sample heater: Link
    Whirlpool 7440/1 Dishwasher - fuse blows, heater short circuit? Whirlpool 7440/1 Dishwasher - fuse blows, heater short circuit?
    The heater resistance of about 25? suggests that it is good because 230V / 25? = 9.2A, and the heater from what I remember is about 2kW, so 230V x 9.2A = 2100W, i.e. approx.
  • #3
    psg
    Level 14  
    Thanks for the info, I will connect a 100W bulb to the heater and check it. Probably after a while of washing, the dishwasher should either blow the fuse in the apartment (power start for the heater) or stop with a squeaking error about a problem with the water heating system.

    1. If the fuse blows with the bulb instead of the heater, it means that the problem is with the programmer, e.g. the HEW relay. A 100W bulb will not burn even though the heater has 2040W, the programmer will have a lower power consumption due to the lack of a heater.

    2. It may also not blow the fuse and end the washing with an error about a problem with water heating (no heater), and the problem will remain because, for example, the washing pump works too slowly, it jams and insufficient water cools the heater.
    I changed the pump 4 years ago and bought the one shown in the pictures. Analyzing in this situation, if the washing pump was inefficient, the thermal fuse of the heater should open like you do, taking a break for the heater, and this was not for me, an individual fuse for the dishwasher in the box and the fuse in the stairwell for the entire apartment.
    So, if the heater is OK, the dishwasher operation test with the bulb remains, or I have not yet checked the resistance for the plug from the programmer side to the heater or it has 25? Could there be any resistance other than 25-30??
  • #4
    ventil
    Level 11  
    I also had a failure of the relay controlling the heater. It is on the programmer's board and it is easy to locate because from it come the heater cables. The connected bulb will simply turn on instead of the heater, the error may only occur some time after the controller registers that the water temperature in the dishwasher does not rise as the washing time passes. It seems to me that it could have charred under these contacts on the bottom and you cannot see it, it could have created a short electric arc which caused the fuse to blow.

    And you have to check whether there is water flowing along the pipes somewhere, or whether something is leaking somewhere. Knock on, I have this dishwasher for 10 years, only there was a failure of this pump and heater, failure of this relay. And with old age, the seal with two O-rings on the rear wall inside, which supplies water to the upper propeller, has broken, but it is also available on the Allegro. Damage to this is caused by lower (escaping water through leakage) water pressure in the water main, which makes washing worse.

    There should also be about 25? on the plug from the programmer side ...
  • #5
    psg
    Level 14  
    How did you fix the failure of the heater control relay? This is the HEW and is also available at auctions?
  • Helpful post
    #6
    ventil
    Level 11  
    The relay did not turn on the heater, I bought it in an electronics store, it cost pennies. I took the old model and showed it to the seller.
  • #7
    psg
    Level 14  
    Ok, thanks for the info, I will write after the test with the bulb.

    Added:

    After cleaning the contacts in the plug and the heater, the dishwasher works. It seems that the breakout of the fuses saved the heater, which would surely burn out due to the play in the plug, there was a short circuit there and it started to melt the plastic. Probably the programmer and its relay for the heater would not work for a long time.