Whirlpoll ADG 7540 Not completing wash cycle

[Struggling100]

Hi, I've seen a problem similar to mine posted on this forum but I need a little more info please. My Whirlpool ADG 7540 starts repeatedly beeping at the same time in the wash cycle. The start light flashes 4 times between pauses and the pre-wash symbol is illuminated ( not the 50deg wash I selected ). When I open the dishwasher there is a little water in the chamber under the fine mesh cover - enough to cover about a third of the black grill covering the pressure switch.
I cleaned the fat and muck out of this black grill ( from within the chamber ) - selected a wash and it worked fine - once. Now its doing the same thing again!. Got a feeling I need to check the outlet hose but there are special jubilee clips on there.... any ideas? Also does anyone know where I can get a service/engineers manual for this appliance - ( I've already had to replace the plastic assembly which holds the wash bars in place - its only 14 months old!)
Many Thanks in advance

 

[Sleepyhead]

You can't get service manuals, only service partners and their engineers get them.
4 flashes is a draining problem.
Either a blockage or the pressure switch is gunged up again or even had it's day. Another possibility is syphoning. Is the drain hose into a stand pipe or a spigot under the sink?
If it's a stand pipe ensure the hose isn't too far into it.

 

[Struggling100]

Thanks Sleepyhead for confirmation that four flashes is a drain problem.

Water definitely drains out, although not completely- it could be a partial blockage in the outlet hose but I am a little reluctant to disconnect the outlet hose from the drain pump ,as there is a metal strap holding the hose onto the pump that looks like it is tightened using a special tool. Do you think I could replace this strap with a jubilee clip if I had to take it off?

I Have operated the pressure switch by gently pressing the diaphragm, through the black grill (with a cotton bud!) and I could hear the switch operating.

The outlet hose goes into a spigot at the same level as the waste pipe, so I guess when the kitchen sink is full and the plug is pulled, water from the sink could siphon back and fill the chamber or block the pipe.

Tonight I'll disconnect the cables from the back of the pressure switch and get a multimeter across it to confirm that the switch contact is making / breaking. I'll then drain the chamber manually and run the dishwasher through a cycle with the outlet hose into a bucket and see if it completes the cycle. I'll let you know the outcome, thanks again, sorry for the "Essay".

 

[Sleepyhead]

Pour boiling water into the sump, preferably over the pressure switch to try and clean out any gunk that may be in there. Although the switch works ok by poking it there may be enough grease in there to prevent it working properly.
As to the drain hose you'll find that normal jubilee clips are too wide but you can get extra thin ones if you hunt for them.
More likely is a restriction in the spigot. Take it apart and clean everything thoroughly.
When testing into a bucket make sure the drain hose rises high enough to prevent syphoning or you'll bring in another problem.

 

[Struggling100]

Cleaned the pressure switch with boiling water, as suggested, and ensured that the outlet was clear of blockages. while machine was out, I took the opportunity to fix the outlet pipe as high as possible ( to avoid syphoning ). Washing like a dream now. Thatnks sleepyhead for your time.

 

[Sleepyhead]

Thanks for letting us know the outcome. Always helps when others are searching for answers.

 

[rugbyboy14]

Thanks for letting us know the outcome. Always helps when others are searching for answers.

Sleepyhead,
wonder if you can help me. I have got the same 4 beeps. followed thos thread and still got the problem.
The blank Grill you talk of is it down in the sump and to the right?
if so it looks like it justs twists off but mine wont budge.
Now on my 4th kettle and letting it soak .... fingers crossed
look forwrd to your reply