Dishwasher woes

[dieselsamurai]

I have a Hotpoint dishwasher which I installed new with the kitchen about 10 years its been generally reliable except for the odd thing getting past the filter somehow and stopping the main pump. Tbh it gets hammered everyday but its very clean inside and runs really quiet i dont really want to replace it as its fairly simple inside . Except a few days ago it started to take ages to complete a cycle then eventually it errored with an F2 on the display with the drain pump is just running constantly . Googling suggest pump inlet blocked or the outlet pipe but these are both fine , to me it seams like its not getting the signal the water level has dropped to the correct level to shut off. Most of the ones I have worked on have a float somewhere or a sensor but I couldnt fine anything turns out it uses air pressure somehow to measure the level but I cant find anything like a sensor for this anywhere. Does anyone have any experience of these ?

this is the only thing I can fine that seems to use air somehow but its only connected to the top of the wash chamber

Google says - The Hotpoint LTF11M132C dishwasher measures its main operational water level using a pressure switch and an air trap system, and it uses a float switch as a safety mechanism for overfilling



but the only thing connected to it appears to be a motor I have no idea what it does !



there is a sensor in the bottom of the filter compartment but they call it a Turbidity Water Sensor: This sensor measures how dirty the water is to determine the appropriate cycle length according to Hotpoint



Its driving me nuts now trying to work out how it works out the level

 

[reb78]

Pump running constantly on a lot.of.dishwashers indicates that the float in the base is in water and so has risen and triggers a switch to run the pump. Had this a few times over the years. Last time it was a neff and the inlet seals for the filler mechanism were leaking into the base. See if the bottom tray has water in it and look for the polystyrene float. I bet if you dry it out then it will run. It's then a case of finding where it's leaking.

 

[Pigeon_Droppings2]

The air ducting might be to support drying function.

My neff also had that sensor too for water quality.

As above check the base for water is the first step....tip the machine.

 

[dieselsamurai]

cheers for replies yeah forgot to mention had base off dry as a bone and checked the float sensor with a meter and its fine



I wonder if the turbidity sensor is also used to check the level as it would know if there was no water between it i guess

Ive got a dish washer in my workshop for cleaning parts and its has a pressure switch with a clear pipe running to it this one has nothing like that

 

[Pigeon_Droppings2]

I wonder if the turbidity sensor is also used to check the level

You can remove and test its working with a multi meter...I seem to remember I took the sensor out and then filled the cap and waved that about across the sendor. It took 3 hands though!

 

[Onoff]

I keep our old Bosch dishwasher going. Periodically I have to clean the "bubble matrix" even though we regularly run cleaner sachets through it. Plus all the red / blue levers and floats get lime scaled up and stick.

 

[dieselsamurai]

You can remove and test its working with a multi meter.

There are quite a few wires going into it , i need to google it to see if there are any measurements I need to be checking against as usual though there are 4 wires and all the same colour

 

[Onoff]

The internal, grey, corrugated waste pipe has complety blocked before now.

 

[dieselsamurai]

I keep our old Bosch dishwasher going. Periodically I have to clean the "bubble matrix" even though we regularly run cleaner sachets through it. Plus all the red / blue levers and floats get lime scaled up and stick.

I wish it was as obvious as that but literally underneath is a drain pump a combined heater and circulation pump and a servo that switches the top nozzle on or off

 

[dieselsamurai]

not much in there

 

[Pigeon_Droppings2]

Not my proudest moment....but it was late and I did not have the correct replacement O ring. Turns out butyl tape has many uses .
I ordered the O rings the next day...one day I may even fit them!

To power the aqua sensor I butchered a USB power cable to get a 5v supply. But I'm not convinced it's a level sensor.

 

[dieselsamurai]

Not my proudest moment....but it was late and I did not have the correct replacement O ring. Turns out butyl tape has many uses .
I ordered the O rings the next day...one day I may even fit them!

To power the aqua sensor I butchered a USB power cable to get a 5v supply. But I'm not convinced it's a level sensor.

got it working and hidden ! its only a tenner so might just order one as I cant see any other way it know when the waters gone

 

[frank horton]

if we get 3 years trouble free from our white goods were happy.....
only buy simple stuff, never use Blue Tooth etc....
then we just buy new....that's if it's not an easy fix.....
If I cant fix it, it's almost 100 euro's for a call out...then the parts have to be ordered and a return visit costs another 30-40 euro's.....
generally stuff aint worth fixing...

 

[badabec]

My old dishwasher has a thin rubber tube from an inverted chamber under the mesh filter to a pressure switch at the top of the machine. As the machine filled with water the air pressure in the chamber increased and triggered the switch.
The rubber tube had blocked with scummy scale. A clean out with some MIG wire and Viakal did the trick.

 

[Onoff]

A clean out with some MIG wire and Viakal did the trick.

Yep, I've spent hours with vinegar and bicarb, long wires etc. In the bubble matrix on mine is a float that rises/falls and operates a switch...or not if it gets really crudded up.

 

[dieselsamurai]

My old dishwasher has a thin rubber tube from an inverted chamber under the mesh filter to a pressure switch at the top of the machine. As the machine filled with water the air pressure in the chamber increased and triggered the switch.
The rubber tube had blocked with scummy scale. A clean out with some MIG wire and Viakal did the trick.

Yeah I was expecting that too but my machine has no tubes coming out of that housing and I cant find a pressure switch listed for it anywhere when ive searched the model number

 

[Pigeon_Droppings2]

On my neff there seemed to be an overflow in the machine side wall leading to the water matrix...worth checking maybe?

 

[MoreWellie]

or the outlet pipe but these are both fine

we moved into a house with an older hotpoint dishwasher and couldn't get it to work. It had lights that flashed which translated to couldn't pump out
assumed it had failed and ordered a new m/c. When I fitted it I had to dismantle part of the drain pipe where it fed in to and found the three inches of horizontal drain pipe under the sink was completely blocked which was no doubt why it couldn't pump out
just saying the problem doesn't always have to be in the dishwasher, sink was draining fine just that short section

 

[dieselsamurai]

we moved into a house with an older hotpoint dishwasher and couldn't get it to work. It had lights that flashed which translated to couldn't pump out
assumed it had failed and ordered a new m/c. When I fitted it I had to dismantle part of the drain pipe where it fed in to and found the three inches of horizontal drain pipe under the sink was completely blocked which was no doubt why it couldn't pump out
just saying the problem doesn't always have to be in the dishwasher, sink was draining fine just that short section

I did check that but im going to set it up remotely when the part comes draining into a bucket with the sides off hopefully i can see or hear where the issue is it it still persists

 

[Cobbler]

we moved into a house with an older hotpoint dishwasher and couldn't get it to work. It had lights that flashed which translated to couldn't pump out
assumed it had failed and ordered a new m/c. When I fitted it I had to dismantle part of the drain pipe where it fed in to and found the three inches of horizontal drain pipe under the sink was completely blocked which was no doubt why it couldn't pump out
just saying the problem doesn't always have to be in the dishwasher, sink was draining fine just that short section

When my friend moved into a new house, connected & loaded dishwasher. It pumped out all over tge utility room floor. Builders hadn’t connected the waste pipe to the drain. Wrecked all the units, builder had to replace them, he argued against it, but friend stuck to his guns.