How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask George-Allsorts Your Own Question
George-Allsorts, Senior Appliance Technicial Manager
Category: Appliance
Satisfied Customers: 1448
Experience:  A whitegoods technician with 30+ years service in Domestic Appliance Service & Repair, and General Mechanical & Electrical Repair
Type Your Appliance Question Here...
George-Allsorts is online now

I have a 17 year old Neff dishwasher which has two problems.

This answer was rated:

I have a 17 year old Neff dishwasher which has two problems. First the dishwasher tablet of soap often does not dissolve even though the trap door has opened. Secondly I find that at the end of each wash 3 to 4 plates still have food dried onto them. I would greatly appreciate your advice on what I can do to solve these problems. With many thanks for your help, Philip Starling
Hello, my name is George..

Can you tell me the full model/Enr of the appliance please

Kindly be patient whilst awaiting any responses from me as I'm not constantly available.
Customer: replied 2 years ago.
I am not clear on what the number of the machine is. The instruction manual has the following numbers on it .7 118 (7705)and s5456 and s5553
Hi Philip, there are three possible causes of this on your dishwasher...

  • Faulty heating element
  • Faulty NTC Sensor on the heating element
  • Burnt or dry joint on the heater relay on the PCB

I have placed these in order of likelyhood


Please remember to rate the assistance I have given you today.. Once rated I will assist you further as far as possible

Customer: replied 2 years ago.
The heating element is surely okay as everything gets really hot by the end of the cycle. Since heating does not appear to be the problem can it be a problem with the NTC sensor or the PCB? If so what are these ,where can I find them and how can I know if they are defective? What about the soap not dissolving? Interestingly the majority of the plates are fine even when the soap has not dissolved? I do not see how I can fairly rate your service at this stage based on the information you have given me.
Hi Philip, If your heater is working then the problem is none of the problems that I have covered above..

Can you check the rotors for clogging... This would cause the rotor not to disseminate the water correctly and therefore would cause both the dishes to remain in a 'not fully cleaned' condition and the soap tablet to remain undisolved.
Customer: replied 2 years ago.
This certainly sounds like a much more likely cause of the problems. However I have checked every one of the jets in both the upper and lower arms and in all of them are free and water can be seen to be coming out of them when I open the door in mid cycle. Is there any reason why the arms should not be rotating which of course I cannot see when I open the doors? Unfortunately I have to go out now and will check in again tomorrow.
Yes, ...

Generally a restriction in the flow of water throughout the appliance (Run a cleaning cycle)

or, Wear in the Circulation Pump of the dishwasher.

Both of these instances would cause problems with the rotating of the rotors

Customer: replied 2 years ago.
After 17 years life your suggestion of wear in the circulation pump sounds the most likely explanation! Would I be able to replace that easily myself? The machine is "built in ". Would I have to extracted it from its housing? With many thanks for your help, Philip
Hi Philip, yes you would need to remove it from the cabinet to be able to work on the appliance. It is possible for you to change the motor yourself, it is not easy but you can do it. However, we need to be sure that it is the motor in the first place. I would run a cleaning cycle with some cleaning aid to clear the tubes and pipes before changing the motor. If there is a blockage in the tubes or pipes, then this would restrict the flow of water and cause the symptoms that you are having.
Customer: replied 2 years ago.
As you suggested I have run a cleaning cycle and will report in a couple of days as to whether it has solved the problem. Your latest reply spoke of changing the motor rather than the pump. do your comments referred to replacing the pump or the motor? Is there a website where I can read the procedure I must follow to replace the pump regards Philip

The motor referred to is the 'Circulation pump' Philip.. but hopefully the may pick-up flow once a cleaning cycle is run


It is now time for me to ask you to take the time to rate the assistance given to you today.. Once rated, I will assist you further if possible.

George-Allsorts and other Appliance Specialists are ready to help you
Customer: replied 2 years ago.
As expected the cleaning cycle had no effect on the problem. I have decided that after 17 years it is time to retire the dishwasher and buy a new one. With thanks for your help regards Philip