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All dry and all hooked up OK. (I’m an industrial automation engineer so this should be within my capabilities! It’s been rather frustrating.)
No, inlet valve cycles on-off-on-off until there is about the right volume of water in the bottom of the chamber and then it pumps out to drain and the cycle restarts. I’m expecting the main pump to start and check if the the pressure switch changes state to indicate that there is adequate water present to run a cycle but it doesn’t seem to – it just drains again.
- While water is flowing in the Fill / Drain LED is steady red.
- During the pause in in-fill the Fill / Drain LED is blinking.
- During drain the fill cycle is continuing.
It’s very strange.
Thanks again for sticking with me on this. I’m developing an unexpected level of intimacy with every component of the dishwasher at this stage!
You were correct to be concerned about the level / pressure switch. I opened it up and found that the rubber diaphragm has a small leak. I don’t have spare so I peel open the housing carefully, cleaned it up, cut a second diaphragm from a bicycle inner tube and reassembled it. I did a full continuity test and it operated properly when blowing into one port with the other one plugged.
I now have the machine on test. It is filling and draining in a continuous loop. I have run the service mode mini-test cycle and the pump main works OK but it doesn’t come on in a regular cycle. I’ve cleaned the water intake filter and restrictor and checked that the impeller reed switch voltage is changing during filling.
Any more ideas?
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How do I get more upload space for images on this site?Thanks again, Dave.
I have the schematic diagram and had figured out that they were checking the relay.Figure 1. Detail of heating relay and pressure switch shrunk to satisfy the 19.5k filesize limit!
I’ve replaced K1 with a Siemens contactor for test purposes. I’ve done a continuity test on the level switch and confirmed that the changeover contacts NO and NC are working when I blow into the switch. I’ve checked for continuity from B1/13 (pressure switch) pins 12 and 22 up to the control board connector. All OK.
Response to your comments:
From the look of the info on an F24 fault the heater relay is shown as a changeover contact arrangement. it is the un energised contacts that are used to determine if the relay is in the open position. It talks about the resistance being above 10 meg and if its not it throws up a code. . any signs of water or damage on the relay or pressure sw contacts.
No all looks OK.
Is the heater got any earth problems. not enough to blow your trip but enough to upset electronics. Try disconnecting heater and put a lamp across it but not an LED one something that will give a decent load.
The heater seems OK. I don’t have a Meggar but a resistance test between the element terminals and earth is over-range. A test lamp lights up in the test mini-cycle and the water heats.
I’m beginning to suspect a control board fault. It may be time to give up and purchase a new one but it seems a shame when everything looks in good condition.
I’ve made significant progress with diagnosis capability but not with solving the problem. I have figured out how to read the fault codes and how to run the various component tests from the front panel. The results are:
- Everything seems to work in test mode.
- In run mode I get an F24 error. The service manual I’m using says that this is a heating relay contact fault but the heater is turning on. (I’ve proved this by wiring a lamp in parallel with the element and in the service mini-program.
I’ve run the test sequence mini-program U1 (section 6.2.1.3 of the manual) and the water warmed up.
The heater / pressure switch is switching. (I continuity checked the double-pole changeover contacts change over when I blow into the switch. I can do about 0.2 bar / 3 psi.)Anyone?
